[Libguestfs] [PATCH] daemon: inspect_fs_windows: Handle parted errors

[Pino Toscano]

On Tuesday, 30 June 2020 10:33:40 CEST Sam Eiderman wrote:
> By creating an empty disk and using it as the first disk of the vm (i.e.
> /dev/sda, /dev/sdb{1,2} contains the windows fses) we change the
> iteration order of the disks.
> This causes inspect_os() to fail since Parted returns a Unix_error if
> the device does not contain any partitions - fix this by handling this
> Unix_error.
> 
> Signed-off-by: Sam Eiderman <sameid at google.com>
> ---
>  daemon/inspect_fs_windows.ml | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/daemon/inspect_fs_windows.ml b/daemon/inspect_fs_windows.ml
> index c4a05bc38..bc6b98b60 100644
> --- a/daemon/inspect_fs_windows.ml
> +++ b/daemon/inspect_fs_windows.ml
> @@ -365,8 +365,10 @@ and map_registry_disk_blob_mbr devices blob =
>      let device =
>        List.find (
>          fun dev ->
> -          Parted.part_get_parttype dev = "msdos" &&
> -            pread dev 4 0x01b8 = diskid
> +          try
> +            Parted.part_get_parttype dev = "msdos" &&
> +              pread dev 4 0x01b8 = diskid
> +          with Unix.Unix_error (Unix.EINVAL, _, _) -> false

The old C inspection code did not check for the partition type:
https://github.com/libguestfs/libguestfs/blob/stable-1.36/lib/inspect-fs-windows.c#L591
The partition type check was added recently:
https://github.com/libguestfs/libguestfs/commit/7b4d13626ff878b124d01ec452a4fd0052934133

TBH I'd rather prefer that we check for the situation explicitly
before, rather than catching a generic EINVAL error. Or, even better,
try to avoid altogether the situation that 7b4d13626ff878 checks,
handling this issue as well.

> @@ -402,7 +404,10 @@ and map_registry_disk_blob_gpt partitions blob =
>          fun part ->
>            let partnum = Devsparts.part_to_partnum part in
>            let device = Devsparts.part_to_dev part in
> -          let typ = Parted.part_get_parttype device in
> +          let typ =
> +            try
> +              Parted.part_get_parttype device
> +            with Unix.Unix_error (Unix.EINVAL, _, _) -> "unknown" in
>            if typ <> "gpt" then false
>            else (

Ditto.

-- 
Pino Toscano
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