Assume that we can always run unshare

With mount --rbind we can bind-mount /proc in a privileged docker
container as it is used by salsaci.

coverage.py

@@ -13,14 +13,13 @@ from collections import defaultdict
 from itertools import product
 
 have_qemu = os.getenv("HAVE_QEMU", "yes") == "yes"
-have_unshare = os.getenv("HAVE_UNSHARE", "yes") == "yes"
 have_binfmt = os.getenv("HAVE_BINFMT", "yes") == "yes"
 run_ma_same_tests = os.getenv("RUN_MA_SAME_TESTS", "yes") == "yes"
 cmd = os.getenv("CMD", "./mmdebstrap")
 
 default_dist = os.getenv("DEFAULT_DIST", "unstable")
 all_dists = ["oldstable", "stable", "testing", "unstable"]
-default_mode = "auto" if have_unshare else "root"
+default_mode = "auto"
 all_modes = ["auto", "root", "unshare", "fakechroot", "chrootless"]
 default_variant = "apt"
 all_variants = [
@@ -271,12 +270,8 @@ def main():
                 tt = "qemu"
             elif test.get("Needs-QEMU", "false") == "true":
                 tt = ("skip", "test needs QEMU")
-            elif mode == "unshare" and not have_unshare:
-                tt = ("skip", "test needs unshare")
             elif test.get("Needs-Root", "false") == "true":
                 tt = "sudo"
-            elif mode == "auto" and not have_unshare:
-                tt = "sudo"
             elif mode == "root":
                 tt = "sudo"
             else:

coverage.sh

@@ -73,7 +73,6 @@ SOURCE_DATE_EPOCH=$(date --date="$(grep-dctrl -s Date -n '' "$mirrordir/dists/$D
 # for traditional sort order that uses native byte values
 export LC_ALL=C.UTF-8
 
-: "${HAVE_UNSHARE:=yes}"
 : "${HAVE_BINFMT:=yes}"
 
 # by default, use the mmdebstrap executable in the current directory together
@@ -81,7 +80,7 @@ export LC_ALL=C.UTF-8
 : "${CMD:=perl -MDevel::Cover=-silent,-nogcov ./mmdebstrap}"
 mirror="http://127.0.0.1/debian"
 
-export HAVE_QEMU HAVE_UNSHARE HAVE_BINFMT RUN_MA_SAME_TESTS DEFAULT_DIST SOURCE_DATE_EPOCH CMD mirror
+export HAVE_QEMU HAVE_BINFMT RUN_MA_SAME_TESTS DEFAULT_DIST SOURCE_DATE_EPOCH CMD mirror
 
 ./coverage.py
 
@@ -99,8 +98,6 @@ cover -delete cover_db >&2
 END
 	if [ "$HAVE_QEMU" = "yes" ]; then
 		./run_qemu.sh
-	elif [ "$HAVE_UNSHARE" != "yes" ]; then
-		./run_null.sh SUDO
 	else
 		./run_null.sh
 	fi

coverage.txt

@@ -5,6 +5,7 @@ Needs-Root: true
 
 Test: as-debootstrap-unshare-wrapper
 Modes: unshare
+Needs-Root: true
 
 Test: help
 
@@ -277,13 +278,14 @@ Skip-If:
  variant == "important" and dist == "oldstable" # /var/lib/systemd/catalog/database differs
 
 Test: create-directory-dry-run
+Modes: root
 
 Test: create-tarball-dry-run
 Variants: any
 Modes: any
 
 Test: unpack-doc-debian
-Modes: any
+Modes: root fakechroot
 Variants: extract
 
 Test: install-doc-debian
@@ -354,7 +356,6 @@ Modes: unshare
 
 Test: pivot_root
 Modes: root unshare
-Skip-If: not have_unshare
 
 Test: jessie-or-older
 Needs-Root: true

tests/as-debootstrap-unshare-wrapper

@@ -15,7 +15,32 @@ if [ "$(id -u)" -eq 0 ] && [ "{{ MODE }}" != "root" ] && [ "{{ MODE }}" != "auto
 	prefix="runuser -u ${SUDO_USER:-user} --"
 fi
 
-$prefix {{ CMD }} --variant=custom --mode={{ MODE }} --setup-hook='env container=lxc debootstrap unstable "$1" {{ MIRROR }}' - /tmp/debian-mm.tar {{ MIRROR }}
+# debootstrap uses apt-config to figure out whether the system running it has
+# any proxies configured and then runs the binary to set the http_proxy
+# environment variable. This will fail if debootstrap is run in a linux user
+# namespace because auto-apt-proxy will see /tmp/.auto-apt-proxy-0 as being
+# owned by the user "nobody" and group "nogroup" and fail with:
+#   insecure cache dir /tmp/.auto-apt-proxy-0. Must be owned by UID 0 and have permissions 700
+# We cannot overwrite a configuration item using the APT_CONFIG environment
+# variable, so instead we use it to set the Dir configuration option
+# to /dev/null to force all apt settings to their defaults.
+# There is currently no better way to disable this behavior. See also:
+# https://bugs.debian.org/1031105
+# https://salsa.debian.org/installer-team/debootstrap/-/merge_requests/90
+AUTOPROXY=
+eval "$(apt-config shell AUTOPROXY Acquire::http::Proxy-Auto-Detect)"
+if [ -n "$AUTOPROXY" ] && [ -x "$AUTOPROXY" ] && [ -e /tmp/.auto-apt-proxy-0 ]; then
+	TMP_APT_CONFIG=$(mktemp)
+	echo "Dir \"/dev/null\";" > "$TMP_APT_CONFIG"
+	chmod 644 "$TMP_APT_CONFIG"
+fi
+
+$prefix {{ CMD }} --variant=custom --mode={{ MODE }} \
+	--setup-hook='env '"${AUTOPROXY:+APT_CONFIG='$TMP_APT_CONFIG'}"' container=lxc debootstrap unstable "$1" {{ MIRROR }}' \
+	- /tmp/debian-mm.tar {{ MIRROR }}
+if [ -n "$AUTOPROXY" ] && [ -x "$AUTOPROXY" ] && [ -e /tmp/.auto-apt-proxy-0 ]; then
+	rm "$TMP_APT_CONFIG"
+fi
 
 mkdir /tmp/debian-mm
 tar --xattrs --xattrs-include='*' -C /tmp/debian-mm -xf /tmp/debian-mm.tar

tests/dev-ptmx

@@ -125,12 +125,13 @@ script -qfec "$prefix {{ CMD }} --mode={{ MODE }} --variant=apt \
 	--customize-hook='chroot \"\$1\" runuser -u user -- python3 -c \"import pty; print(pty.openpty())\"' \
 	--customize-hook='chroot \"\$1\" script -c \"echo foobar\"' \
 	--customize-hook='chroot \"\$1\" runuser -u user -- env --chdir=/home/user script -c \"echo foobar\"' \
-	--customize-hook='chroot \"\$1\" apt-get install --yes doc-debian 2>&1 | tee /tmp/log' \
+	--customize-hook='chroot \"\$1\" apt-get install --yes doc-debian 2>&1 | tee \"\$1\"/tmp/log' \
 	--customize-hook=\"copy-in /tmp/test.c /tmp\" \
 	--customize-hook='chroot \"\$1\" gcc /tmp/test.c -o /tmp/test' \
 	--customize-hook='chroot \"\$1\" /tmp/test' \
 	--customize-hook='chroot \"\$1\" runuser -u user -- /tmp/test' \
 	--customize-hook='rm \"\$1\"/tmp/test \"\$1\"/tmp/test.c' \
+	--customize-hook=\"copy-out /tmp/log /tmp\" \
 	{{ DIST }} /dev/null {{ MIRROR }}" /dev/null
 
 fail=0

tests/dist-using-codename

@@ -4,8 +4,10 @@
 
 set -eu
 export LC_ALL=C.UTF-8
-trap "rm -f Release; rm -rf /tmp/debian-chroot" EXIT INT TERM
+trap "rm -f Release; rm -rf /tmp/debian-chroot.tar /tmp/expected" EXIT INT TERM
 /usr/lib/apt/apt-helper download-file "{{ MIRROR }}/dists/{{ DIST }}/Release" Release
 codename=$(awk '/^Codename: / { print $2; }' Release)
-{{ CMD }} --mode={{ MODE }} --variant=apt "$codename" /tmp/debian-chroot {{ MIRROR }}
+{{ CMD }} --mode={{ MODE }} --variant=apt "$codename" /tmp/debian-chroot.tar {{ MIRROR }}
-echo "deb {{ MIRROR }} $codename main" | diff -u - /tmp/debian-chroot/etc/apt/sources.list
+echo "deb {{ MIRROR }} $codename main" > /tmp/expected
+tar --to-stdout --extract --file /tmp/debian-chroot.tar ./etc/apt/sources.list \
+	| diff -u /tmp/expected -

tests/pivot_root

@@ -16,10 +16,6 @@ if [ "$(id -u)" -eq 0 ] && [ "{{ MODE }}" != "root" ] && [ "{{ MODE }}" != "auto
 	prefix="runuser -u ${SUDO_USER:-user} --"
 fi
 
-MMDEBSTRAP=
-[ -e /usr/bin/mmdebstrap ] && MMDEBSTRAP=/usr/bin/mmdebstrap
-[ -e ./mmdebstrap ] && MMDEBSTRAP=./mmdebstrap
-
 $prefix {{ CMD }} --mode={{ MODE }} --variant=apt \
 	--include=mount \
 	{{ DIST }} /tmp/chroot1.tar {{ MIRROR }}
@@ -28,14 +24,16 @@ if [ {{ MODE }} = "unshare" ]; then
 	# calling pivot_root in root mode does not work for mysterious reasons:
 	# pivot_root: failed to change root from `.' to `mnt': Invalid argument
 	$prefix {{ CMD }} --mode={{ MODE }} --variant=apt --include=mount \
-		--customize-hook="upload $MMDEBSTRAP /$MMDEBSTRAP" \
+		--customize-hook='mkdir -p "$1/mnt" "$1/oldroot"' \
-		--customize-hook='chmod +x "$1"/'"$MMDEBSTRAP" \
+		--customize-hook='[ ! -e /usr/bin/mmdebstrap ] || cp -aT /usr/bin/mmdebstrap "$1/usr/bin/mmdebstrap"' \
-		--customize-hook='mount -o rbind "$1" /mnt && cd /mnt && /sbin/pivot_root . mnt' \
+		--customize-hook='[ ! -e ./mmdebstrap ] || cp -aT ./mmdebstrap "$1/mnt/mmdebstrap"' \
+		--customize-hook='mount -o rbind "$1" /mnt && cd /mnt && /sbin/pivot_root . oldroot' \
 		--customize-hook='unshare -U echo nested unprivileged unshare' \
-		--customize-hook="/$MMDEBSTRAP"' --mode=unshare --variant=apt --include=mount {{ DIST }} /tmp/chroot3.tar {{ MIRROR }}' \
+		--customize-hook='env --chdir=/mnt {{ CMD }} --mode=unshare --variant=apt --include=mount {{ DIST }} /tmp/chroot3.tar {{ MIRROR }}' \
 		--customize-hook='copy-out /tmp/chroot3.tar /tmp' \
-		--customize-hook='rm "$1/'"$MMDEBSTRAP"'"' \
+		--customize-hook='rm -f "/usr/bin/mmdebstrap" "/mnt/mmdebstrap"' \
-		--customize-hook='umount -l mnt sys' \
+		--customize-hook='umount -l oldroot sys' \
+		--customize-hook='rmdir /oldroot' \
 		{{ DIST }} /tmp/chroot2.tar {{ MIRROR }}
 
 		cmp /tmp/chroot1.tar /tmp/chroot2.tar || diffoscope /tmp/chroot1.tar /tmp/chroot2.tar
@@ -44,11 +42,12 @@ if [ {{ MODE }} = "unshare" ]; then
 fi
 
 $prefix {{ CMD }} --mode={{ MODE }} --variant=apt --include=mount \
-	--customize-hook="upload $MMDEBSTRAP /$MMDEBSTRAP" \
+	--customize-hook='mkdir -p "$1/mnt"' \
-	--customize-hook='chmod +x "$1"/'"$MMDEBSTRAP" \
+	--customize-hook='[ ! -e /usr/bin/mmdebstrap ] || cp -aT /usr/bin/mmdebstrap "$1/usr/bin/mmdebstrap"' \
-	--chrooted-customize-hook="/$MMDEBSTRAP"' --mode=unshare --variant=apt --include=mount {{ DIST }} /tmp/chroot3.tar {{ MIRROR }}' \
+	--customize-hook='[ ! -e ./mmdebstrap ] || cp -aT ./mmdebstrap "$1/mnt/mmdebstrap"' \
+	--chrooted-customize-hook='env --chdir=/mnt {{ CMD }} --mode=unshare --variant=apt --include=mount {{ DIST }} /tmp/chroot3.tar {{ MIRROR }}' \
 	--customize-hook='copy-out /tmp/chroot3.tar /tmp' \
-	--customize-hook='rm "$1/'"$MMDEBSTRAP"'"' \
+	--customize-hook='rm -f "$1/usr/bin/mmdebstrap" "$1/mnt/mmdebstrap"' \
 	{{ DIST }} /tmp/chroot2.tar {{ MIRROR }}
 
 cmp /tmp/chroot1.tar /tmp/chroot2.tar || diffoscope /tmp/chroot1.tar /tmp/chroot2.tar

tests/unshare-include-deb

@@ -34,9 +34,8 @@ Description: dummypkg
 END
 dpkg-deb --build "/tmp/dummypkg" "/tmp/dummypkg.deb"
 
-# make the .deb only redable by user which will exclude the unshared user
+# make the .deb only redable by its owner which will exclude the unshared user
 chmod 600 /tmp/dummypkg.deb
-chown user /tmp/dummypkg.deb
 
 ret=0
 $prefix {{ CMD }} --variant=apt --mode={{ MODE }} --include="/tmp/dummypkg.deb" \