From 930d7a7fb777c4558b5417ae00a4cf57b10169a2 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Fri, 25 Nov 2011 21:16:38 -0500
Subject: tst_fs_struct: add program to help check ABI compatibility of
 ext2fs_filsys

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 lib/ext2fs/Makefile.in     |  6 ++++
 lib/ext2fs/tst_fs_struct.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 87 insertions(+)
 create mode 100644 lib/ext2fs/tst_fs_struct.c

diff --git a/lib/ext2fs/Makefile.in b/lib/ext2fs/Makefile.in
index a9795a36..d9b04f9e 100644
--- a/lib/ext2fs/Makefile.in
+++ b/lib/ext2fs/Makefile.in
@@ -267,6 +267,12 @@ tst_super_size: tst_super_size.o
 	$(E) "	LD $@"
 	$(Q) $(CC) -o tst_super_size tst_super_size.o 
 
+tst_fs_struct.o: $(srcdir)/tst_fs_struct.c $(srcdir)/ext2fs.h
+
+tst_fs_struct: tst_fs_struct.o
+	$(E) "	LD $@"
+	$(Q) $(CC) -o tst_fs_struct tst_fs_struct.o 
+
 tst_inode_size.o: $(srcdir)/tst_inode_size.c $(srcdir)/ext2_fs.h
 
 tst_inode_size: tst_inode_size.o
diff --git a/lib/ext2fs/tst_fs_struct.c b/lib/ext2fs/tst_fs_struct.c
new file mode 100644
index 00000000..6f44df18
--- /dev/null
+++ b/lib/ext2fs/tst_fs_struct.c
@@ -0,0 +1,81 @@
+/*
+ * This testing program checks the offset of the ext2_filsys structure
+ *
+ * Copyright (C) 2007 by Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Library
+ * General Public License, version 2.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "ext2fs.h"
+
+struct struct_ext2_filsys fs;
+
+#ifndef offsetof
+#define offsetof(type, member)  __builtin_offsetof (type, member)
+#endif
+#define check_field(x) cur_offset = do_field(#x, sizeof(fs.x),		\
+					offsetof(struct struct_ext2_filsys, x), \
+					cur_offset)
+
+static int do_field(const char *field, size_t size, int offset, int cur_offset)
+{
+	if (offset != cur_offset) {
+		printf("\t(padding %d bytes?)\n", offset - cur_offset);
+	}
+	printf("%8d %-30s %3u\n", offset, field, (unsigned) size);
+	return offset + size;
+}
+
+int main(int argc, char **argv)
+{
+#if (__GNUC__ >= 4)
+	int cur_offset = 0;
+
+	printf("%8s %-30s %3s\n", "offset", "field", "size");
+	check_field(magic);
+	check_field(io);
+	check_field(flags);
+	check_field(device_name);
+	check_field(super);
+	check_field(blocksize);
+	check_field(fragsize);
+	check_field(group_desc_count);
+	check_field(desc_blocks);
+	check_field(group_desc);
+	check_field(inode_blocks_per_group);
+	check_field(inode_map);
+	check_field(block_map);
+	check_field(get_blocks);
+	check_field(check_directory);
+	check_field(write_bitmaps);
+	check_field(read_inode);
+	check_field(write_inode);
+	check_field(badblocks);
+	check_field(dblist);
+	check_field(stride);
+	check_field(orig_super);
+	check_field(image_header);
+	check_field(umask);
+	check_field(now);
+	check_field(cluster_ratio_bits);
+	check_field(reserved);
+	check_field(priv_data);
+	check_field(icache);
+	check_field(image_io);
+	check_field(get_alloc_block);
+	check_field(block_alloc_stats);
+	check_field(mmp_buf);
+	check_field(mmp_cmp);
+	check_field(mmp_fd);
+	check_field(mmp_last_written);
+	printf("Ending offset is %d\n\n", cur_offset);
+#endif
+	exit(0);
+}
-- 
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