add support for generating squashfs images using tar2sqfs

coverage.sh

@@ -49,7 +49,7 @@ if [ ! -e shared/mmdebstrap ] || [ mmdebstrap -nt shared/mmdebstrap ]; then
 fi
 
 starttime=
-total=122
+total=123
 skipped=0
 runtests=0
 i=1
@@ -547,6 +547,29 @@ else
 	runtests=$((runtests+1))
 fi
 
+print_header "mode=$defaultmode,variant=apt: test squashfs image"
+cat << END > shared/test.sh
+#!/bin/sh
+set -eu
+export LC_ALL=C.UTF-8
+$CMD --mode=$defaultmode --variant=apt $DEFAULT_DIST /tmp/debian-chroot.squashfs $mirror
+printf 'hsqs' | cmp --bytes=4 /tmp/debian-chroot.squashfs -
+# workaround for https://github.com/AgentD/squashfs-tools-ng/issues/37
+sed 's#\\([^.]\\)/\$#\\1#' tar1.txt | sort > /tmp/tar1noslash.txt
+sqfs2tar --no-skip --root-becomes . /tmp/debian-chroot.squashfs | tar -t | sort | diff -u /tmp/tar1noslash.txt -
+rm /tmp/debian-chroot.squashfs /tmp/tar1noslash.txt
+END
+if [ "$HAVE_QEMU" = "yes" ]; then
+	./run_qemu.sh
+	runtests=$((runtests+1))
+elif [ "$defaultmode" = "root" ]; then
+	./run_null.sh SUDO
+	runtests=$((runtests+1))
+else
+	./run_null.sh
+	runtests=$((runtests+1))
+fi
+
 print_header "mode=auto,variant=apt: test auto-mode without unshare capabilities"
 cat << END > shared/test.sh
 #!/bin/sh

make_mirror.sh

@@ -407,7 +407,7 @@ if [ "$HAVE_QEMU" = "yes" ]; then
 	tmpdir="$(mktemp -d)"
 	trap "cleanuptmpdir; cleanup_newcachedir" EXIT INT TERM
 
-	pkgs=perl-doc,linux-image-amd64,systemd-sysv,perl,arch-test,fakechroot,fakeroot,mount,uidmap,proot,qemu-user-static,binfmt-support,qemu-user,dpkg-dev,mini-httpd,libdevel-cover-perl,debootstrap,procps,apt-cudf,aspcud
+	pkgs=perl-doc,linux-image-amd64,systemd-sysv,perl,arch-test,fakechroot,fakeroot,mount,uidmap,proot,qemu-user-static,binfmt-support,qemu-user,dpkg-dev,mini-httpd,libdevel-cover-perl,debootstrap,procps,apt-cudf,aspcud,squashfs-tools-ng
 	if [ "$HOSTARCH" = amd64 ] && [ "$RUN_MA_SAME_TESTS" = "yes" ]; then
 		arches=amd64,armhf
 		pkgs="$pkgs,libfakechroot:armhf,libfakeroot:armhf"

mmdebstrap

@@ -2707,16 +2707,9 @@ sub main() {
 
     # figure out whether a tarball has to be created in the end
     $options->{maketar} = 0;
+    $options->{makesqfs} = 0;
     if (defined $tar_compressor or $options->{target} =~ /\.tar$/ or $options->{target} eq '-') {
 	$options->{maketar} = 1;
-	if (any { $_ eq $options->{variant} } ('extract', 'custom') and any { $_ eq $options->{mode} } ('fakechroot', 'proot')) {
-	    info "creating a tarball in fakechroot mode or proot mode might fail in extract and custom variants because there might be no tar inside the chroot";
-	}
-	# try to fail early if target tarball cannot be opened for writing
-	if ($options->{target} ne '-') {
-	    open my $fh, '>', $options->{target} or error "cannot open $options->{target} for writing: $!";
-	    close $fh;
-	}
 	# check if the compressor is installed
 	if (defined $tar_compressor) {
 	    my $pid = fork() // error "fork() failed: $!";
@@ -2730,9 +2723,31 @@ sub main() {
 		error ("failed to start " . (join " ", @{$tar_compressor}));
 	    }
 	}
+    } elsif ($options->{target} =~ /\.(squashfs|sqfs)$/) {
+	$options->{makesqfs} = 1;
+	# check if tar2sqfs is installed
+	my $pid = fork() // error "fork() failed: $!";
+	if ($pid == 0) {
+	    open(STDOUT, '>', '/dev/null') or error "cannot open /dev/null for writing: $!";
+	    open(STDIN, '<', '/dev/null') or error "cannot open /dev/null for reading: $!";
+	    exec ('tar2sqfs', '--version') or error ("cannot exec tar2sqfs --version: $!");
+	}
+	waitpid $pid, 0;
+	if ($? != 0) {
+	    error ("failed to start tar2sqfs --version");
+	}
     }
 
-    if ($options->{maketar}) {
+    if ($options->{maketar} or $options->{makesqfs}) {
+	if (any { $_ eq $options->{variant} } ('extract', 'custom') and any { $_ eq $options->{mode} } ('fakechroot', 'proot')) {
+	    info "creating a tarball or squashfs image in fakechroot mode or proot mode might fail in extract and custom variants because there might be no tar inside the chroot";
+	}
+	# try to fail early if target tarball or squashfs image cannot be
+	# opened for writing
+	if ($options->{target} ne '-') {
+	    open my $fh, '>', $options->{target} or error "cannot open $options->{target} for writing: $!";
+	    close $fh;
+	}
 	# since the output is a tarball, we create the rootfs in a temporary
 	# directory
 	$options->{root} = tempdir(
@@ -2837,7 +2852,7 @@ sub main() {
 
     my $devtar = '';
     # We always craft the /dev entries ourselves if a tarball is to be created
-    if ($options->{maketar}) {
+    if ($options->{maketar} or $options->{makesqfs}) {
 	foreach my $file (@devfiles) {
 	    my ($fname, $mode, $type, $linkname, $devmajor, $devminor) = @{$file};
 	    my $entry = pack('a100 a8 a8 a8 a12 a12 A8 a1 a100 a8 a32 a32 a8 a8 a155 x12',
@@ -2901,7 +2916,7 @@ sub main() {
 
 	    close $childsock;
 
-	    if ($options->{maketar}) {
+	    if ($options->{maketar} or $options->{makesqfs}) {
 		info "creating tarball...";
 
 		# redirect tar output to the writing end of the pipe so that the
@@ -2943,7 +2958,7 @@ sub main() {
 
 	    close $childsock;
 
-	    if ($options->{maketar}) {
+	    if ($options->{maketar} or $options->{makesqfs}) {
 		info "creating tarball...";
 
 		# redirect tar output to the writing end of the pipe so that the
@@ -3306,7 +3321,7 @@ sub main() {
 
     close $parentsock;
 
-    if ($options->{maketar}) {
+    if ($options->{maketar} or $options->{makesqfs}) {
 	# we use eval() so that error() doesn't take this process down and
 	# thus leaves the setup() process without a parent
 	eval {
@@ -3315,7 +3330,17 @@ sub main() {
 		    error "cannot copy to standard output: $!";
 		}
 	    } else {
-		if (defined $tar_compressor) {
+		if ($options->{makesqfs} or defined $tar_compressor) {
+		    my @argv = ();
+		    if ($options->{makesqfs}) {
+			push @argv, 'tar2sqfs',
+			    '--quiet', '--no-skip', '--force', '--exportable',
+			    '--compressor', 'xz',
+			    '--block-size', '1048576',
+			    $options->{target};
+		    } else {
+			push @argv, @{$tar_compressor};
+		    }
 		    POSIX::sigprocmask(SIG_BLOCK, $sigset) or error "Can't block signals: $!";
 		    my $cpid = fork() // error "fork() failed: $!";
 		    if ($cpid == 0) {
@@ -3327,14 +3352,19 @@ sub main() {
 
 			# unblock all delayed signals (and possibly handle them)
 			POSIX::sigprocmask(SIG_UNBLOCK, $sigset) or error "Can't unblock signals: $!";
-			open(STDOUT, '>', $options->{target}) or error "cannot open $options->{target} for writing: $!";
+
+			if ($options->{makesqfs}) {
+			    open(STDOUT, '>', '/dev/null') or error "cannot open /dev/null for writing: $!";
+			} else {
+			    open(STDOUT, '>', $options->{target}) or error "cannot open $options->{target} for writing: $!";
+			}
 			open(STDIN, '<&', $rfh) or error "cannot open file handle for reading: $!";
-			exec { $tar_compressor->[0] } @{$tar_compressor} or error ("cannot exec " . (join " ", @{$tar_compressor}) . ": $!");
+			exec { $argv[0] } @argv or error ("cannot exec " . (join " ", @argv) . ": $!");
 		    }
 		    POSIX::sigprocmask(SIG_UNBLOCK, $sigset) or error "Can't unblock signals: $!";
 		    waitpid $cpid, 0;
 		    if ($? != 0) {
-			error ("failed to start " . (join " ", @{$tar_compressor}));
+			error ("failed to start " . (join " ", @argv));
 		    }
 		} else {
 		    if(!copy($rfh, $options->{target})) {
@@ -3359,7 +3389,7 @@ sub main() {
     # change signal handler message
     $waiting_for = "cleanup";
 
-    if ($options->{maketar} and -e $options->{root}) {
+    if (($options->{maketar} or $options->{makesqfs}) and -e $options->{root}) {
 	info "removing tempdir $options->{root}...";
 	if ($options->{mode} eq 'unshare') {
 	    # We don't have permissions to remove the directory outside
@@ -3447,25 +3477,29 @@ installed inside the chroot.  If any mirror contains a tor+xxx URI, then the
 apt-transport-tor package will be installed inside the chroot.
 
 The optional I<TARGET> argument can either be the path to a directory, the
-path to a tarball filename or C<->. If I<TARGET> ends with C<.tar>, or with
+path to a tarball filename, the path to a squashfs image or C<->. If I<TARGET>
-any of the filename extensions listed in the section B<COMPRESSION>, then
+ends with C<.tar>, or with any of the filename extensions listed in the
-I<TARGET> will be interpreted as a path to a tarball filename. If I<TARGET> is
+section B<COMPRESSION>, then I<TARGET> will be interpreted as a path to a
-the path to a tarball filename or if I<TARGET> is C<-> or if no I<TARGET> was
+tarball filename. If I<TARGET> ends with C<.squashfs> or C<.sqfs>, then
-specified, B<mmdebstrap> will create a temporary chroot directory in
+I<TARGET> will be interpreted as a path to a squashfs image. If I<TARGET> is
-C<$TMPDIR> or F</tmp>. If I<TARGET> is the path to a tarball filename,
+the path to a tarball filename or a squashfs image or if I<TARGET> is C<-> or
-B<mmdebstrap> will create a tarball of that directory and store it as
+if no I<TARGET> was specified, B<mmdebstrap> will create a temporary chroot
-I<TARGET>, optionally applying a compression algorithm as indicated by its
+directory in C<$TMPDIR> or F</tmp>. If I<TARGET> is the path to a tarball
+filename, B<mmdebstrap> will create a tarball of that directory and store it
+as I<TARGET>, optionally applying a compression algorithm as indicated by its
 filename extension. If I<TARGET> is C<-> or if no I<TARGET> was specified,
 then an uncompressed tarball of that directory will be sent to standard
 output. When B<mmdebstrap> creates a tarball it also stores extended
 attributes. To preserve the extended attributes, you have to pass B<--xattrs
---xattrs-include='*'> to tar when extracting the tarball. If I<TARGET> does
+--xattrs-include='*'> to tar when extracting the tarball. If I<TARGET> is the
-not end in C<.tar> or with any of the filename extensions listed in the
+path to a squashfs image, B<mmdebstrap> will create an xz compressed image
-section B<COMPRESSION>, then I<TARGET> will be interpreted as the path to a
+with a blocksize of 1048576 bytes. If I<TARGET> does neither end with C<.tar>
-directory. If the directory already exists, it must either be empty or only
+nor with any of the filename extensions listed in the section B<COMPRESSION>,
-contain an empty C<lost+found> directory.  If a directory is chosen as output
+nor with C<.squashfs> or C<.sqfs>, then I<TARGET> will be interpreted as the
-in any other mode than B<sudo>, then its contents will have wrong ownership
+path to a directory. If the directory already exists, it must either be empty
-information and special device files will be missing.
+or only contain an empty C<lost+found> directory.  If a directory is chosen as
+output in any other mode than B<sudo>, then its contents will have wrong
+ownership information and special device files will be missing.
 
 The I<SUITE> may be a valid release code name (eg, sid, stretch, jessie) or a
 symbolic name (eg, unstable, testing, stable, oldstable). Any suite name that
@@ -3938,6 +3972,10 @@ create device nodes:
 
     $ mmdebstrap unstable | tar --delete ./dev > unstable-chroot.tar
 
+Instead of a tarball, a squashfs image can be created:
+
+    $ mmdebstrap unstable unstable-chroot.squashfs
+
 By default, debootstrapping a stable distribution will add mirrors for security
 and updates to the sources.list.