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FROM debian:stretch-slim
RUN apt-get update && apt-get install -y \
bzip2 \
curl \
gcc \
gnupg dirmngr \
make \
&& rm -rf /var/lib/apt/lists/*
# pub 1024D/ACC9965B 2006-12-12
# Key fingerprint = C9E9 416F 76E6 10DB D09D 040F 47B7 0C55 ACC9 965B
# uid Denis Vlasenko <vda.linux@googlemail.com>
# sub 1024g/2C766641 2006-12-12
RUN gpg --keyserver ha.pool.sks-keyservers.net --recv-keys C9E9416F76E610DBD09D040F47B70C55ACC9965B
ENV BUSYBOX_VERSION 1.29.1
RUN set -ex; \
tarball="busybox-${BUSYBOX_VERSION}.tar.bz2"; \
curl -fL -o busybox.tar.bz2 "https://busybox.net/downloads/$tarball"; \
curl -fL -o busybox.tar.bz2.sig "https://busybox.net/downloads/$tarball.sig"; \
gpg --batch --verify busybox.tar.bz2.sig busybox.tar.bz2; \
mkdir -p /usr/src/busybox; \
tar -xf busybox.tar.bz2 -C /usr/src/busybox --strip-components 1; \
rm busybox.tar.bz2*
WORKDIR /usr/src/busybox
# CONFIG_LAST_SUPPORTED_WCHAR: see https://github.com/docker-library/busybox/issues/13 (UTF-8 input)
# As long as we rely on libnss, we have to have libc.so anyhow, so
# we've removed CONFIG_STATIC here for now... :cry:
RUN set -ex; \
\
setConfs=' \
CONFIG_AR=y \
CONFIG_FEATURE_AR_CREATE=y \
CONFIG_FEATURE_AR_LONG_FILENAMES=y \
CONFIG_LAST_SUPPORTED_WCHAR=0 \
'; \
\
unsetConfs=' \
CONFIG_FEATURE_SYNC_FANCY \
'; \
\
make defconfig; \
\
for conf in $unsetConfs; do \
sed -i \
-e "s!^$conf=.*\$!# $conf is not set!" \
.config; \
done; \
\
for confV in $setConfs; do \
conf="${confV%=*}"; \
sed -i \
-e "s!^$conf=.*\$!$confV!" \
-e "s!^# $conf is not set\$!$confV!" \
.config; \
if ! grep -q "^$confV\$" .config; then \
echo "$confV" >> .config; \
fi; \
done; \
\
make oldconfig; \
\
# trust, but verify
for conf in $unsetConfs; do \
! grep -q "^$conf=" .config; \
done; \
for confV in $setConfs; do \
grep -q "^$confV\$" .config; \
done;
RUN set -ex \
&& make -j "$(nproc)" \
busybox \
&& ./busybox --help \
&& mkdir -p rootfs/bin \
&& ln -vL busybox rootfs/bin/ \
\
&& ln -vL "$(which getconf)" rootfs/bin/getconf \
\
# hack hack hack hack hack
# with glibc, static busybox uses libnss for DNS resolution :(
&& mkdir -p rootfs/etc \
&& cp /etc/nsswitch.conf rootfs/etc/ \
&& mkdir -p rootfs/lib \
&& ln -sT lib rootfs/lib64 \
&& set -- \
rootfs/bin/busybox \
rootfs/bin/getconf \
/lib/"$(gcc -print-multiarch)"/libnss*.so.* \
# libpthread is part of glibc: http://stackoverflow.com/a/11210463/433558
/lib/"$(gcc -print-multiarch)"/libpthread*.so.* \
&& while [ "$#" -gt 0 ]; do \
f="$1"; shift; \
fn="$(basename "$f")"; \
if [ -e "rootfs/lib/$fn" ]; then continue; fi; \
if [ "${f#rootfs/}" = "$f" ]; then \
if [ "${fn#ld-}" = "$fn" ]; then \
ln -vL "$f" "rootfs/lib/$fn"; \
else \
cp -v "$f" "rootfs/lib/$fn"; \
fi; \
fi; \
set -- "$@" $(ldd "$f" | awk ' \
$1 ~ /^\// { print $1; next } \
$2 == "=>" && $3 ~ /^\// { print $3; next } \
'); \
done \
\
&& chroot rootfs /bin/getconf _NPROCESSORS_ONLN \
\
&& chroot rootfs /bin/busybox --install /bin
# download a few extra files from buildroot (/etc/passwd, etc)
RUN set -ex; \
buildrootVersion='2017.11.1'; \
mkdir -p rootfs/etc; \
for f in passwd shadow group; do \
curl -fL -o "rootfs/etc/$f" "https://git.busybox.net/buildroot/plain/system/skeleton/etc/$f?id=$buildrootVersion"; \
done; \
# set expected permissions, etc too (https://git.busybox.net/buildroot/tree/system/device_table.txt)
curl -fL -o buildroot-device-table.txt "https://git.busybox.net/buildroot/plain/system/device_table.txt?id=$buildrootVersion"; \
awk ' \
!/^#/ { \
if ($2 != "d" && $2 != "f") { \
printf "error: unknown type \"%s\" encountered in line %d: %s\n", $2, NR, $0 > "/dev/stderr"; \
exit 1; \
} \
sub(/^\/?/, "rootfs/", $1); \
if ($2 == "d") { \
printf "mkdir -p %s\n", $1; \
} \
printf "chmod %s %s\n", $3, $1; \
} \
' buildroot-device-table.txt | bash -Eeuo pipefail -x; \
rm buildroot-device-table.txt
# create missing home directories
RUN set -ex \
&& cd rootfs \
&& for userHome in $(awk -F ':' '{ print $3 ":" $4 "=" $6 }' etc/passwd); do \
user="${userHome%%=*}"; \
home="${userHome#*=}"; \
home="./${home#/}"; \
if [ ! -d "$home" ]; then \
mkdir -p "$home"; \
chown "$user" "$home"; \
chmod 755 "$home"; \
fi; \
done
# test and make sure it works
RUN chroot rootfs /bin/sh -xec 'true'
# ensure correct timezone (UTC)
RUN set -ex; \
ln -vL /usr/share/zoneinfo/UTC rootfs/etc/localtime; \
[ "$(chroot rootfs date +%Z)" = 'UTC' ]
# test and make sure DNS works too
RUN cp -L /etc/resolv.conf rootfs/etc/ \
&& chroot rootfs /bin/sh -xec 'nslookup google.com' \
&& rm rootfs/etc/resolv.conf