Re: [Libguestfs] [PATCH guestfs-tools] diff: Don't compare st_dev or st_ino fields

See comment for details. Link: https://listman.redhat.com/archives/libguestfs/2023-July/032061.html --- diff/diff.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/diff/diff.c b/diff/diff.c index fb66a2bbd3..b6344b4ec2 100644 --- a/diff/diff.c +++ b/diff/diff.c @@ -717,8 +717,20 @@ changed (guestfs_h *g1, struct file *file1, output_string ("changed:"); #define COMPARE_STAT(n) \ if (file1->stat->n != file2->stat->n) output_string (#n) - COMPARE_STAT (st_dev); - COMPARE_STAT (st_ino); + /* Comparing st_dev and st_ino is disabled for now, see the longer + * discussion here: + * https://listman.redhat.com/archives/libguestfs/2023-July/032061.html + * Even if we fixed the libguestfs API to do translation of this + * field correctly, it seems unlikely that there would ever be a + * meaningful difference in the st_dev or st_ino fields. We + * already know the fields refer to the same filename. Is it + * interesting that the file might have moved to a different disk? + * Everything else is comparing the content or direct metadata of + * the file, but st_dev and st_ino represent the metadata of the + * filesystem which is (arguably) different. + */ +// COMPARE_STAT (st_dev); +// COMPARE_STAT (st_ino); COMPARE_STAT (st_mode); COMPARE_STAT (st_nlink); COMPARE_STAT (st_uid);

This tool will find differences in filenames, file sizes, checksums, extended attributes, file content and more from a virtual machine or disk image. However it does not look at the boot loader, unused space between partitions or within filesystems, "hidden" sectors and so on. In other words, it is not a security or forensics tool.