[Libguestfs] [PATCH] inspector: Fix virt-inspector on *BSD guests (RHBZ#1144138).

[Pino Toscano]

On Thursday, 5 October 2017 17:36:09 CEST Richard W.M. Jones wrote:
> ---
>  inspector/inspector.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/inspector/inspector.c b/inspector/inspector.c
> index 3583c61df..30d279987 100644
> --- a/inspector/inspector.c
> +++ b/inspector/inspector.c
> @@ -347,6 +347,7 @@ output_root (xmlTextWriterPtr xo, char *root)
>    char buf[32];
>    char *canonical_root;
>    size_t size;
> +  int is_bsd;
>  
>    XMLERROR (-1, xmlTextWriterStartElement (xo, BAD_CAST "operatingsystem"));
>  
> @@ -362,6 +363,10 @@ output_root (xmlTextWriterPtr xo, char *root)
>    if (STRNEQ (str, "unknown"))
>      XMLERROR (-1,
>  	      xmlTextWriterWriteElement (xo, BAD_CAST "name", BAD_CAST str));
> +  is_bsd =
> +    STREQ (str, "freebsd") ||
> +    STREQ (str, "netbsd") ||
> +    STREQ (str, "openbsd");
>    free (str);
>  
>    str = guestfs_inspect_get_arch (g, root);
> @@ -451,8 +456,13 @@ output_root (xmlTextWriterPtr xo, char *root)
>  
>    /* We need to mount everything up in order to read out the list of
>     * applications and the icon, ie. everything below this point.
> +   *
> +   * XXX As a workaround for BSD guests, because the Linux kernel
> +   * driver cannot just mount a UFS filesystem, we must disable this
> +   * for all *BSD operating systems.  We cannot read the apps or icon
> +   * from *BSD anyway.
>     */

This is not true, libguestfs can actually read those properties.  The
proof of that is running virt-inspector with --no-applications, and
--no-icon shows the proper details (such as product name, mount points,
host name, etc) of the guest.

The trick here is what check_for_filesystem_on in daemon/inspect_fs.ml
does, by trying few mount options for ufs filesystems: usually one of
those attempts succeeds, so we extract the information from that
partition.  Later on in virt-inspector, though, these extra mount
options are not retained, so it fails.

The two possible options I had in mind were:
a) duplicate the same mount logic also in virt-inspector, which is ugly, duplicates code, etc
b) save these extra mount options, exposing them via a new inspect_*
   API: IMHO it is ugly as well, since it would "make official" the
   extra mount attempts hack tried in inspect_fs.ml
but both are ugly, in one way or another, so I did not implement either
of them.

Anyway, IMHO this patch is not the correct approach.

-- 
Pino Toscano
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