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make_mirror.sh: never leave the cache in an inconsistent state by atomically switching symlinks

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Johannes 'josch' Schauer 2018-12-28 07:44:54 +01:00
parent 8d92412380
commit b113771a81
Signed by untrusted user: josch
GPG key ID: F2CBA5C78FBD83E1
3 changed files with 91 additions and 34 deletions
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2
coverage.sh
View file

@ -2,7 +2,7 @@
set -eu set -eu
mirrordir="./shared/debian" mirrordir="./shared/cache/debian"
./make_mirror.sh ./make_mirror.sh

121
make_mirror.sh
View file

@ -2,8 +2,32 @@
set -eu set -eu
mirrordir="./shared/debian" # This script fills either cache.A or cache.B with new content and then
cachedir="./shared/cache" # atomically switches the cache symlink from one to the other at the end.
# This way, at no point will the cache be in an non-working state, even
# when this script got canceled at any point.
# Working with two directories also automatically prunes old packages in
# the local repository.
if [ -e "./shared/cache.A" ] && [ -e "./shared/cache.B" ]; then
echo "both ./shared/cache.A and ./shared/cache.B exist" >&2
echo "was a former run of the script aborted?" >&2
echo "cache symlink points to $(readlink ./shared/cache)" >&2
exit 1
fi
if [ -e "./shared/cache.A" ]; then
oldcache=cache.A
newcache=cache.B
else
oldcache=cache.B
newcache=cache.A
fi
oldcachedir="./shared/$oldcache"
newcachedir="./shared/$newcache"
oldmirrordir="$oldcachedir/debian"
newmirrordir="$newcachedir/debian"
mirror="http://deb.debian.org/debian" mirror="http://deb.debian.org/debian"
arch1=$(dpkg --print-architecture) arch1=$(dpkg --print-architecture)
@ -15,8 +39,8 @@ components=main
: "${HAVE_QEMU:=yes}" : "${HAVE_QEMU:=yes}"
if [ -e "$mirrordir/dists/unstable/Release" ]; then if [ -e "$oldmirrordir/dists/unstable/Release" ]; then
http_code=$(curl --output /dev/null --silent --location --head --time-cond "$mirrordir/dists/unstable/Release" --write-out '%{http_code}' "$mirror/dists/unstable/Release") http_code=$(curl --output /dev/null --silent --location --head --time-cond "$oldmirrordir/dists/unstable/Release" --write-out '%{http_code}' "$mirror/dists/unstable/Release")
case "$http_code" in case "$http_code" in
200) ;; # need update 200) ;; # need update
304) echo up-to-date; exit 0;; 304) echo up-to-date; exit 0;;
@ -24,14 +48,6 @@ if [ -e "$mirrordir/dists/unstable/Release" ]; then
esac esac
fi fi
# use -f because the files might not exist
for dist in stable testing unstable; do
for variant in minbase buildd -; do
rm -f "$cachedir/debian-$dist-$variant.tar"
done
done
rm -f "$cachedir/debian-unstable.qcow"
for nativearch in $arch1 $arch2; do for nativearch in $arch1 $arch2; do
for dist in stable testing unstable; do for dist in stable testing unstable; do
rootdir=$(mktemp --directory) rootdir=$(mktemp --directory)
@ -67,12 +83,12 @@ END
# file, copy all old *.deb packages from the mirror to # file, copy all old *.deb packages from the mirror to
# /var/cache/apt/archives so that apt will not re-download *.deb # /var/cache/apt/archives so that apt will not re-download *.deb
# packages that we already have # packages that we already have
if [ -e "$mirrordir/dists/$dist/main/binary-$nativearch/Packages.gz" ]; then if [ -e "$oldmirrordir/dists/$dist/main/binary-$nativearch/Packages.gz" ]; then
gzip -dc "$mirrordir/dists/$dist/main/binary-$nativearch/Packages.gz" \ gzip -dc "$oldmirrordir/dists/$dist/main/binary-$nativearch/Packages.gz" \
| grep-dctrl --no-field-names --show-field=Package,Version,Architecture,Filename '' \ | grep-dctrl --no-field-names --show-field=Package,Version,Architecture,Filename '' \
| paste -sd " \n" \ | paste -sd " \n" \
| while read name ver arch fname; do | while read name ver arch fname; do
if [ ! -e "$mirrordir/$fname" ]; then if [ ! -e "$oldmirrordir/$fname" ]; then
continue continue
fi fi
# apt stores deb files with the colon encoded as %3a while # apt stores deb files with the colon encoded as %3a while
@ -85,7 +101,7 @@ END
# doesn't recognize symlinks # doesn't recognize symlinks
# we cannot do a hardlink because the two # we cannot do a hardlink because the two
# directories might be on different devices # directories might be on different devices
cp -a "$mirrordir/$fname" "$aptname" cp -a "$oldmirrordir/$fname" "$aptname"
echo "$aptname" >> "$rootdir/oldaptnames" echo "$aptname" >> "$rootdir/oldaptnames"
done done
fi fi
@ -103,10 +119,10 @@ END
APT_CONFIG="$rootdir/etc/apt/apt.conf" apt-get --yes install $pkgs APT_CONFIG="$rootdir/etc/apt/apt.conf" apt-get --yes install $pkgs
# to be able to also test gpg verification, we need to create a mirror # to be able to also test gpg verification, we need to create a mirror
mkdir -p "$mirrordir/dists/$dist/" "$mirrordir/dists/$dist/main/binary-$nativearch/" mkdir -p "$newmirrordir/dists/$dist/" "$newmirrordir/dists/$dist/main/binary-$nativearch/"
curl --location "$mirror/dists/$dist/Release" > "$mirrordir/dists/$dist/Release" curl --location "$mirror/dists/$dist/Release" > "$newmirrordir/dists/$dist/Release"
curl --location "$mirror/dists/$dist/Release.gpg" > "$mirrordir/dists/$dist/Release.gpg" curl --location "$mirror/dists/$dist/Release.gpg" > "$newmirrordir/dists/$dist/Release.gpg"
curl --location "$mirror/dists/$dist/main/binary-$nativearch/Packages.gz" > "$mirrordir/dists/$dist/main/binary-$nativearch/Packages.gz" curl --location "$mirror/dists/$dist/main/binary-$nativearch/Packages.gz" > "$newmirrordir/dists/$dist/main/binary-$nativearch/Packages.gz"
# the deb files downloaded by apt must be moved to their right locations in the # the deb files downloaded by apt must be moved to their right locations in the
# pool directory # pool directory
@ -117,7 +133,7 @@ END
# stripping the epoch from the filename and will break once mirrors change. # stripping the epoch from the filename and will break once mirrors change.
# This way, it doesn't matter where the mirror ends up storing the package. # This way, it doesn't matter where the mirror ends up storing the package.
> "$rootdir/newaptnames" > "$rootdir/newaptnames"
gzip -dc "$mirrordir/dists/$dist/main/binary-$nativearch/Packages.gz" \ gzip -dc "$newmirrordir/dists/$dist/main/binary-$nativearch/Packages.gz" \
| grep-dctrl --no-field-names --show-field=Package,Version,Architecture,Filename,MD5sum '' \ | grep-dctrl --no-field-names --show-field=Package,Version,Architecture,Filename,MD5sum '' \
| paste -sd " \n" \ | paste -sd " \n" \
| while read name ver arch fname md5; do | while read name ver arch fname md5; do
@ -129,8 +145,8 @@ END
if [ -e "$aptname" ]; then if [ -e "$aptname" ]; then
# make sure that we found the right file by checking its hash # make sure that we found the right file by checking its hash
echo "$md5 $aptname" | md5sum --check echo "$md5 $aptname" | md5sum --check
mkdir -p "$mirrordir/$dir" mkdir -p "$newmirrordir/$dir"
mv "$aptname" "$mirrordir/$fname" mv "$aptname" "$newmirrordir/$fname"
echo "$aptname" >> "$rootdir/newaptnames" echo "$aptname" >> "$rootdir/newaptnames"
fi fi
done done
@ -154,9 +170,6 @@ END
done done
done done
# now fill the cache with new content
mkdir -p "$cachedir"
if [ "$HAVE_QEMU" = "yes" ]; then if [ "$HAVE_QEMU" = "yes" ]; then
# We must not use any --dpkgopt here because any dpkg options still # We must not use any --dpkgopt here because any dpkg options still
# leak into the chroot with chrootless mode. # leak into the chroot with chrootless mode.
@ -200,6 +213,8 @@ END
cat << 'END' > "$tmpdir/worker.sh" cat << 'END' > "$tmpdir/worker.sh"
#!/bin/sh #!/bin/sh
mount -t 9p -o trans=virtio,access=any mmdebstrap /mnt mount -t 9p -o trans=virtio,access=any mmdebstrap /mnt
# need to restart mini-httpd because we mounted different content into www-root
systemctl restart mini-httpd
( (
cd /mnt; cd /mnt;
if [ -e cover_db.img ]; then if [ -e cover_db.img ]; then
@ -218,9 +233,11 @@ umount /mnt
systemctl poweroff systemctl poweroff
END END
chmod +x "$tmpdir/worker.sh" chmod +x "$tmpdir/worker.sh"
cat << 'END' > "$tmpdir/mini-httpd" # initially we serve from the new cache so that debootstrap can grab
# the new package repository and not the old
cat << END > "$tmpdir/mini-httpd"
START=1 START=1
DAEMON_OPTS="-h 127.0.0.1 -p 80 -u nobody -dd /mnt -i /var/run/mini-httpd.pid -T UTF-8" DAEMON_OPTS="-h 127.0.0.1 -p 80 -u nobody -dd /mnt/$newcache -i /var/run/mini-httpd.pid -T UTF-8"
END END
cat << 'END' > "$tmpdir/hosts" cat << 'END' > "$tmpdir/hosts"
127.0.0.1 localhost 127.0.0.1 localhost
@ -242,13 +259,13 @@ END
copy-in "$tmpdir/mini-httpd" /etc/default : \ copy-in "$tmpdir/mini-httpd" /etc/default : \
copy-in "$tmpdir/hosts" /etc/ : copy-in "$tmpdir/hosts" /etc/ :
rm "$tmpdir/extlinux.conf" "$tmpdir/worker.sh" "$tmpdir/mini-httpd" "$tmpdir/hosts" "$tmpdir/debian-unstable.tar" "$tmpdir/mmdebstrap.service" rm "$tmpdir/extlinux.conf" "$tmpdir/worker.sh" "$tmpdir/mini-httpd" "$tmpdir/hosts" "$tmpdir/debian-unstable.tar" "$tmpdir/mmdebstrap.service"
qemu-img convert -O qcow2 "$tmpdir/debian-unstable.img" "$cachedir/debian-unstable.qcow" qemu-img convert -O qcow2 "$tmpdir/debian-unstable.img" "$newcachedir/debian-unstable.qcow"
rm "$tmpdir/debian-unstable.img" rm "$tmpdir/debian-unstable.img"
rmdir "$tmpdir" rmdir "$tmpdir"
fi fi
mirror="http://127.0.0.1/debian" mirror="http://127.0.0.1/debian"
SOURCE_DATE_EPOCH=$(date --date="$(grep-dctrl -s Date -n '' "$mirrordir/dists/unstable/Release")" +%s) SOURCE_DATE_EPOCH=$(date --date="$(grep-dctrl -s Date -n '' "$newmirrordir/dists/unstable/Release")" +%s)
for dist in stable testing unstable; do for dist in stable testing unstable; do
for variant in minbase buildd -; do for variant in minbase buildd -; do
# skip because of different userids for apt/systemd # skip because of different userids for apt/systemd
@ -266,9 +283,49 @@ set -eu
export LC_ALL=C.UTF-8 export LC_ALL=C.UTF-8
export SOURCE_DATE_EPOCH=$SOURCE_DATE_EPOCH export SOURCE_DATE_EPOCH=$SOURCE_DATE_EPOCH
debootstrap --no-merged-usr --variant=$variant $dist /tmp/debian-$dist-debootstrap $mirror debootstrap --no-merged-usr --variant=$variant $dist /tmp/debian-$dist-debootstrap $mirror
tar --sort=name --mtime=@$SOURCE_DATE_EPOCH --clamp-mtime --numeric-owner --one-file-system -C /tmp/debian-$dist-debootstrap -c . > "cache/debian-$dist-$variant.tar" tar --sort=name --mtime=@$SOURCE_DATE_EPOCH --clamp-mtime --numeric-owner --one-file-system -C /tmp/debian-$dist-debootstrap -c . > "$newcache/debian-$dist-$variant.tar"
rm -r /tmp/debian-$dist-debootstrap rm -r /tmp/debian-$dist-debootstrap
END END
./run_qemu.sh SUDO if [ "$HAVE_QEMU" = "yes" ]; then
cachedir=$newcachedir ./run_qemu.sh
else
./run_null.sh SUDO
fi
done done
done done
# now replace the minihttpd config with one that serves the new repository
# create a temporary directory because "copy-in" cannot rename the file
tmpdir="$(mktemp -d)"
cat << END > "$tmpdir/mini-httpd"
START=1
DAEMON_OPTS="-h 127.0.0.1 -p 80 -u nobody -dd /mnt/cache -i /var/run/mini-httpd.pid -T UTF-8"
END
guestfish -a "$newcachedir/debian-unstable.qcow" -i copy-in "$tmpdir/mini-httpd" /etc/default
rm "$tmpdir/mini-httpd"
rmdir "$tmpdir"
# delete possibly leftover symlink
if [ -e ./shared/cache.tmp ]; then
rm ./shared/cache.tmp
fi
# now atomically switch the symlink to point to the other directory
ln -s $newcache ./shared/cache.tmp
mv --no-target-directory ./shared/cache.tmp ./shared/cache
# be very careful with removing the old directory
for dist in stable testing unstable; do
for variant in minbase buildd -; do
if [ -e "$oldcachedir/debian-$dist-$variant.tar" ]; then
rm "$oldcachedir/debian-$dist-$variant.tar"
fi
done
if [ -e "$oldcachedir/debian/dists/$dist" ]; then
rm --one-file-system --recursive "$oldcachedir/debian/dists/$dist"
fi
done
if [ -e $oldcachedir/debian-unstable.qcow ]; then
rm --one-file-system $oldcachedir/debian-unstable.qcow
fi
rm --one-file-system --recursive $oldcachedir/debian/pool/main
# now the rest should only be empty directories
find $oldcachedir -depth -print0 | xargs -0 rmdir

2
run_qemu.sh
View file

@ -2,7 +2,7 @@
set -eu set -eu
cachedir="./shared/cache" : "${cachedir:=./shared/cache}"
tmpdir="$(mktemp -d)" tmpdir="$(mktemp -d)"
cleanup() { cleanup() {