[Libguestfs] [PATCH 0/1] inspect: Fix a bug in the *BSD root detection

Hello, I've been reading the *BSD detection code in check_filesystem() in inspect-fs.c in order to write a patch for OpenBSD detection that is missing. Both, in FreeBSD and in NetBSD you have this piece of code: /* Ignore /dev/sda1 which is a shadow of the real root filesystem * that is probably /dev/sda5 (see: * http://www.freebsd.org/doc/handbook/disk-organization.html) */ if (m->im_type == MOUNTABLE_DEVICE && match (g, m->im_device, re_first_partition)) return 0; This assumption is not always true. First of all, the MBR partition that hosts the disklabel could be any of the primary partitions. Not just the first one. The OpenBSD installer for example will by default use the 4th partition. I'm pretty sure you can change this in FreeBSD and NetBSD too. The other thing is that /dev/sda5 will not always be there. The problem is the weird way the kernel maps the disklabel partitions: https://github.com/torvalds/linux/blob/master/block/partitions/msdos.c#L3... The kernel will not map a disklabel subpartition if it has the same boundaries with the parent (MBR) partition or if its boundaries exceed the disklabel. In the disklabel's partition table 'a' is always the root partition, 'b' is the swap, in OpenBSD and FreeBSD 'c' is the full hard disk. In NetBSD 'c' is the disklabel partition itself and 'd' is the full hard disk. Those partitions are invalid for the kernel. If I have a *BSD installation with just root and swap, the kernel will show 3 partitions: /dev/sda1 for the disklabel, /dev/sda5 for root and /dev/sda6 for swap, but If I only have a root partition then this will likely have the same boundaries with the MBR partition and the kernel will not map it again to /dev/sda5. In this case inspect_os() will completely miss the OS. I tried to fix this by removing the code above and checking again for duplicated *BSD root partitions after all the file systems have been scanned to unmark the is_root. It's not the prettiest thing in the world but I couldn't think of something better. Nikos Nikos Skalkotos (1): inspect: Fix a bug in the *BSD root detection src/guestfs-internal.h | 1 + src/inspect-fs.c | 55 +++++++++++++++++++++++++++++++++----------------- src/inspect.c | 6 ++++++ 3 files changed, 43 insertions(+), 19 deletions(-) -- 2.1.3