make fakechroot mode bit-by-bit identical to the others

coverage.sh

@@ -753,7 +753,15 @@ else
 fi
 runuser -u user -- $CMD --mode=unshare --variant=$variant $DEFAULT_DIST /tmp/debian-chroot-unshare.$format $mirror
 cmp /tmp/debian-chroot-root.$format /tmp/debian-chroot-unshare.$format
-rm /tmp/debian-chroot-root.$format /tmp/debian-chroot-unshare.$format
+rm /tmp/debian-chroot-unshare.$format
+case $variant in essential|apt|minbase)
+	# /etc/ld.so.cache differs with some variants
+	runuser -u user -- $CMD --mode=fakechroot --variant=$variant $DEFAULT_DIST /tmp/debian-chroot-fakechroot.$format $mirror
+	cmp /tmp/debian-chroot-root.$format /tmp/debian-chroot-fakechroot.$format
+	rm /tmp/debian-chroot-fakechroot.$format
+	;;
+esac
+rm /tmp/debian-chroot-root.$format
 END
 		if [ "$HAVE_QEMU" = "yes" ]; then
 			./run_qemu.sh
@@ -1208,12 +1216,7 @@ prefix=
 mkdir /tmp/mnt
 mount /tmp/debian-chroot.ext2 /tmp/mnt
 rmdir /tmp/mnt/lost+found
-# in fakechroot mode, we use a fake ldconfig, so we have to
+tar -C /tmp/mnt -c . | tar -t | sort | diff -u tar1.txt -
-# artificially add some files
-{ tar -C /tmp/mnt -c . | tar -t;
-  [ "$mode" = "fakechroot" ] && printf "./etc/ld.so.cache\n./var/cache/ldconfig/\n";
-  [ "$mode" = "fakechroot" ] && printf "./etc/.pwd.lock\n";
-} | sort | diff -u tar1.txt -
 umount /tmp/mnt
 rmdir /tmp/mnt
 rm /tmp/debian-chroot.ext2
@@ -1239,9 +1242,7 @@ fi
 adduser --gecos user --disabled-password user
 sysctl -w kernel.unprivileged_userns_clone=0
 runuser -u user -- $CMD --mode=auto --variant=apt $DEFAULT_DIST /tmp/debian-chroot.tar.gz $mirror
-{ tar -tf /tmp/debian-chroot.tar.gz;
+tar -tf /tmp/debian-chroot.tar.gz | sort | diff -u tar1.txt -
-  printf "./etc/ld.so.cache\n./var/cache/ldconfig/\n./etc/.pwd.lock\n";
-} | sort | diff -u tar1.txt -
 rm /tmp/debian-chroot.tar.gz
 END
 if [ "$HAVE_QEMU" = "yes" ]; then
@@ -2651,12 +2652,7 @@ echo upload-customize | cmp /tmp/download-customize -
 echo sync-in-setup | cmp /tmp/sync-out-setup/file -
 echo sync-in-essential | cmp /tmp/sync-out-essential/file -
 echo sync-in-customize | cmp /tmp/sync-out-customize/file -
-# in fakechroot mode, we use a fake ldconfig, so we have to
+tar -tf /tmp/debian-chroot.tar | sort | diff -u tar1.txt -
-# artificially add some files
-{ tar -tf /tmp/debian-chroot.tar;
-  [ "$mode" = "fakechroot" ] && printf "./etc/ld.so.cache\n./var/cache/ldconfig/\n";
-  [ "$mode" = "fakechroot" ] && [ "$variant" != "essential" ] && printf "./etc/.pwd.lock\n";
-} | sort | diff -u tar1.txt -
 rm /tmp/debian-chroot.tar \
 	/tmp/copy-in-setup /tmp/copy-in-essential /tmp/copy-in-customize \
 	/tmp/copy-out-setup /tmp/copy-out-essential /tmp/copy-out-customize \
@@ -3192,12 +3188,7 @@ fi
 prefix=
 [ "\$(id -u)" -eq 0 ] && prefix="runuser -u user --"
 \$prefix $CMD --mode=$mode --variant=$variant $DEFAULT_DIST /tmp/debian-chroot.tar $mirror
-# in fakechroot mode, we use a fake ldconfig, so we have to
+tar -tf /tmp/debian-chroot.tar | sort | diff -u "./$variant.txt" -
-# artificially add some files
-{ tar -tf /tmp/debian-chroot.tar;
-  [ "$mode" = "fakechroot" ] && printf "./etc/ld.so.cache\n./var/cache/ldconfig/\n";
-  [ "$mode" = "fakechroot" ] && [ "$variant" != "essential" ] && printf "./etc/.pwd.lock\n";
-} | sort | diff -u "./$variant.txt" -
 rm /tmp/debian-chroot.tar
 END
 		if [ "$HAVE_QEMU" = "yes" ]; then
@@ -3714,8 +3705,6 @@ prefix=
 \$prefix $CMD --mode=$mode --variant=apt --architectures=arm64 $DEFAULT_DIST /tmp/debian-chroot.tar $mirror
 # we ignore differences between architectures by ignoring some files
 # and renaming others
-# in fakechroot mode, we use a fake ldconfig, so we have to
-# artificially add some files
 # in proot mode, some extra files are put there by proot
 { tar -tf /tmp/debian-chroot.tar \
 	| grep -v '^\./lib/ld-linux-aarch64\.so\.1$' \
@@ -3723,7 +3712,6 @@ prefix=
 	| grep -v '^\./usr/share/doc/[^/]\+/changelog\(\.Debian\)\?\.arm64\.gz$' \
 	| sed 's/aarch64-linux-gnu/x86_64-linux-gnu/' \
 	| sed 's/arm64/amd64/';
-	[ "$mode" = "fakechroot" ] && printf "./etc/ld.so.cache\n./var/cache/ldconfig/\n./etc/.pwd.lock\n";
 } | sort > tar2.txt
 { cat tar1.txt \
 	| grep -v '^\./usr/bin/i386$' \

mmdebstrap

@@ -251,6 +251,24 @@ sub get_tar_compressor {
     return;
 }
 
+# avoid dependency on String::ShellQuote by implementing the mechanism
+# from python's shlex.quote function
+sub shellescape {
+    my $string = shift;
+    if (length $string == 0) {
+        return "''";
+    }
+    # search for occurrences of characters that are not safe
+    # the 'a' regex modifier makes sure that \w only matches ASCII
+    if ($string !~ m/[^\w@\%+=:,.\/-]/a) {
+        return $string;
+    }
+    # wrap the string in single quotes and handle existing single quotes by
+    # putting them outside of the single-quoted string
+    $string =~ s/'/'"'"'/g;
+    return "'$string'";
+}
+
 sub test_unshare_userns {
     my $verbose = shift;
     if ($EFFECTIVE_USER_ID == 0) {
@@ -1977,16 +1995,15 @@ sub run_setup() {
         copy($tmpfile, \*STDERR);
     }
 
-    if (any { $_ eq $options->{mode} } ('fakechroot', 'proot')) {
+    if (none { $_ eq $options->{mode} } ('fakechroot', 'proot')) {
         # Apt dropping privileges to another user than root is not useful in
         # fakechroot and proot mode because all users are faked and thus there
-        # is no real privilege difference anyways. Thus, we also print no
+        # is no real privilege difference anyways. We could set
-        # warning message in this case.
+        # APT::Sandbox::User "root" in fakechroot and proot mode but we don't
-        open my $fh, '>>', $tmpfile
+        # because if we would, then /var/cache/apt/archives/partial/ and
-          or error "cannot open $tmpfile for appending: $!";
+        # /var/lib/apt/lists/partial/ would not be owned by the _apt user
-        print $fh "APT::Sandbox::User \"root\";\n";
+        # if mmdebstrap was run in fakechroot or proot mode.
-        close $fh;
+        #
-    } else {
         # when apt-get update is run by the root user, then apt will attempt to
         # drop privileges to the _apt user. This will fail if the _apt user
         # does not have permissions to read the root directory. In that case,
@@ -2643,11 +2660,28 @@ sub run_prepare {
         # /etc/fakechroot/debootstrap.env and
         # /etc/fakechroot/chroot.env
         {
+            # we add "$@" before "-r" such that any other "-r" options will be
+            # overwritten by the one we set
+            my $escapedroot = shellescape $options->{root};
+            my ($fh, $filename) = tempfile(
+                "mmdebstrap.ldconfig.XXXXXXXXXXXX",
+                UNLINK => 1,
+                TMPDIR => 1
+            );
+            print $fh <<EOF;
+#!/bin/sh
+set -e
+if [ ! -e $escapedroot/sbin/ldconfig ]; then exit 0; fi
+mkdir --mode=700 --parents $escapedroot/var/cache/ldconfig
+$escapedroot/sbin/ldconfig "\$@" -r $escapedroot
+EOF
+            close $fh;
+            chmod 0755, $filename or error "cannot chmod $filename";
             my @fakechrootsubst = ();
             foreach my $d ('/usr/sbin', '/usr/bin', '/sbin', '/bin') {
                 push @fakechrootsubst, "$d/chroot=/usr/sbin/chroot.fakechroot";
                 push @fakechrootsubst, "$d/mkfifo=/bin/true";
-                push @fakechrootsubst, "$d/ldconfig=/bin/true";
+                push @fakechrootsubst, "$d/ldconfig=$filename";
                 push @fakechrootsubst, "$d/ldd=/usr/bin/ldd.fakechroot";
                 push @fakechrootsubst, "$d/ischroot=/bin/true";
             }
@@ -5684,6 +5718,12 @@ sub main() {
                 }
 
                 if ($options->{mode} eq 'fakechroot') {
+                    # By default, FAKECHROOT_EXCLUDE_PATH includes /proc and
+                    # /sys which means that the resulting tarball will contain
+                    # the permission and ownership information of /proc and
+                    # /sys from the outside, which we want to avoid.
+                    ## no critic (Variables::RequireLocalizedPunctuationVars)
+                    $ENV{FAKECHROOT_EXCLUDE_PATH} = "/dev";
                     # Fakechroot requires tar to run inside the chroot or
                     # otherwise absolute symlinks will include the path to the
                     # root directory