Test ability to reproduce parsed images

For all the images we generate from json, try also
to regenerated them and ensure we get the same bits.

To do the dumping we add the internal composefs-dump tool.

Signed-off-by: Alexander Larsson <[email protected]>

tools/Makefile.am

@@ -2,7 +2,7 @@ COMPOSEFS_HASH_CFLAGS = -DUSE_OBSTACK=0 -DTESTING=0 -DUSE_DIFF_HASH=0
 
 bin_PROGRAMS = mkcomposefs composefs-info
 sbin_PROGRAMS = mount.composefs
-noinst_PROGRAMS =
+noinst_PROGRAMS = composefs-dump
 
 if USE_YAJL
 noinst_PROGRAMS += composefs-from-json
@@ -27,6 +27,9 @@ composefs_info_SOURCES = composefs-info.c ../libcomposefs/hash.c
 composefs_info_CFLAGS = $(AM_CFLAGS) $(COMPOSEFS_HASH_CFLAGS)
 composefs_info_LDADD = ../libcomposefs/libcomposefs.la
 
+composefs_dump_SOURCES = composefs-dump.c
+composefs_dump_LDADD = ../libcomposefs/libcomposefs.la
+
 composefs_fuse_SOURCES = cfs-fuse.c
 composefs_fuse_LDADD =   ../libcomposefs/libcomposefs.la $(FUSE3_LIBS)
 composefs_fuse_CFLAGS =  $(AM_CFLAGS) $(FUSE3_CFLAGS)
@@ -45,6 +48,6 @@ endif
 EXTRA_DIST = test-checksums.sh $(patsubst %,test-assets/%,${TEST_ASSETS_SMALL}) $(patsubst %,test-assets/%.sha256_erofs,${TEST_ASSETS_SMALL})
 
 check-checksums:
-	$(srcdir)/test-checksums.sh "${WRITER_JSON_PREFIX} $(builddir)/composefs-from-json" "$(srcdir)/test-assets" "${TEST_ASSETS}"
+	$(srcdir)/test-checksums.sh "${WRITER_JSON_PREFIX} $(builddir)" "$(srcdir)/test-assets" "${TEST_ASSETS}"
 
 check: check-checksums

tools/composefs-dump.c

@@ -0,0 +1,94 @@
+/* lcfs
+   Copyright (C) 2023 Alexander Larsson <[email protected]>
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#define _GNU_SOURCE
+
+#include "config.h"
+
+#include "libcomposefs/lcfs-writer.h"
+#include "libcomposefs/lcfs-utils.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <err.h>
+#include <error.h>
+#include <errno.h>
+#include <fcntl.h>
+
+static void usage(const char *argv0)
+{
+	fprintf(stderr, "usage: %s SRC DEST\n", argv0);
+}
+
+static ssize_t write_cb(void *_file, void *buf, size_t count)
+{
+	FILE *file = _file;
+
+	return fwrite(buf, 1, count, file);
+}
+
+int main(int argc, char **argv)
+{
+	const char *bin = argv[0];
+	int fd;
+	struct lcfs_node_s *root;
+	const char *src_path = NULL;
+	const char *dst_path = NULL;
+	struct lcfs_write_options_s options = { 0 };
+
+	if (argc <= 1) {
+		fprintf(stderr, "No source path specified\n");
+		usage(bin);
+		exit(1);
+	}
+	src_path = argv[1];
+
+	if (argc <= 2) {
+		fprintf(stderr, "No destination path specified\n");
+		usage(bin);
+		exit(1);
+	}
+	dst_path = argv[2];
+
+	fd = open(src_path, O_RDONLY | O_CLOEXEC);
+	if (fd < 0) {
+		err(EXIT_FAILURE, "Failed to open '%s'", src_path);
+	}
+
+	root = lcfs_load_node_from_fd(fd);
+	if (root == NULL) {
+		err(EXIT_FAILURE, "Failed to load '%s'", src_path);
+	}
+
+	close(fd);
+
+	options.format = LCFS_FORMAT_EROFS;
+
+	FILE *out_file = fopen(dst_path, "we");
+	if (out_file == NULL)
+		error(EXIT_FAILURE, errno, "failed to open '%s'", dst_path);
+
+	options.file = out_file;
+	options.file_write_cb = write_cb;
+
+	if (lcfs_write_to(root, &options) < 0)
+		error(EXIT_FAILURE, errno, "cannot write file");
+
+	lcfs_node_unref(root);
+
+	return 0;
+}

tools/test-checksums.sh

@@ -1,12 +1,13 @@
 #!/usr/bin/bash
 
-WRITER_JSON="$1"
+BINDIR="$1"
 ASSET_DIR="$2"
 TEST_ASSETS="$3"
 
 set -e
 tmpfile=$(mktemp /tmp/lcfs-test.XXXXXX)
-trap 'rm -rf -- "$tmpfile"' EXIT
+tmpfile2=$(mktemp /tmp/lcfs-test.XXXXXX)
+trap 'rm -rf -- "$tmpfile" "$tmpfile2"' EXIT
 
 for format in erofs ; do
     for file in ${TEST_ASSETS} ; do
@@ -21,12 +22,19 @@ for format in erofs ; do
             CAT=cat
         fi
 
-        $CAT $ASSET_DIR/$file | $WRITER_JSON --format=$format --out=$tmpfile -
+        $CAT $ASSET_DIR/$file | ${BINDIR}/composefs-from-json --format=$format --out=$tmpfile -
         SHA=$(sha256sum $tmpfile | awk "{print \$1}")
 
         if [ $SHA != $EXPECTED_SHA ]; then
             echo Invalid $format checksum of file generated from $file: $SHA, expected $EXPECTED_SHA
             exit 1
         fi
+
+        # Ensure dump reproduces the same file
+        ${BINDIR}/composefs-dump $tmpfile $tmpfile2
+        if ! cmp $tmpfile $tmpfile2; then
+            echo Dump is not reproducible
+            exit 1
+        fi
     done
 done