[Libguestfs] [libnbd PATCH] info: Let exit status reflect any failures during NBD_OPT_INFO

[Richard W.M. Jones]

On Thu, Mar 04, 2021 at 09:30:53AM -0600, Eric Blake wrote:
> It turns out that at least nbdkit's testsuite was relying on a
> non-zero exit status from nbdinfo when purposefully attempting to get
> info on an invalid export name.  Printing as much information as
> possible instead of going silent becaus of one error is good, but any
> time we print to stderr, the exit status should reflect that.
> 
> Fixes: 5473e34fc1 (info: Don't kill --list early just because one opt_info fails)
> Reported-by: Rich Jones <rjones at redhat.com>

Just tested it locally and it worked for me to fix nbdkit.

I see it's been pushed so I'll add it to Fedora and rebuild both
libnbd and nbdkit there now.

Thanks,

Rich.

> 
> This fixes the regression we were seeing in nbdkit.
> 
>  info/nbdinfo.c | 25 +++++++++++++++----------
>  1 file changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/info/nbdinfo.c b/info/nbdinfo.c
> index 4b18ab27..3dfc463f 100644
> --- a/info/nbdinfo.c
> +++ b/info/nbdinfo.c
> @@ -58,9 +58,9 @@ DEFINE_VECTOR_TYPE (uint32_vector, uint32_t)
>  static int collect_context (void *opaque, const char *name);
>  static int collect_export (void *opaque, const char *name,
>                             const char *desc);
> -static void list_one_export (struct nbd_handle *nbd, const char *desc,
> +static bool list_one_export (struct nbd_handle *nbd, const char *desc,
>                               bool first, bool last);
> -static void list_all_exports (struct nbd_handle *nbd1, const char *uri);
> +static bool list_all_exports (struct nbd_handle *nbd1, const char *uri);
>  static void print_json_string (const char *);
>  static char *get_content (struct nbd_handle *, int64_t size);
>  static int extent_callback (void *user_data, const char *metacontext,
> @@ -124,6 +124,7 @@ main (int argc, char *argv[])
>    int tls_negotiated;
>    char *output = NULL;
>    size_t output_len = 0;
> +  bool list_okay = true;
> 
>    progname = argv[0];
> 
> @@ -336,9 +337,9 @@ main (int argc, char *argv[])
>      }
> 
>      if (!list_all)
> -      list_one_export (nbd, NULL, true, true);
> +      list_okay = list_one_export (nbd, NULL, true, true);
>      else
> -      list_all_exports (nbd, argv[optind]);
> +      list_okay = list_all_exports (nbd, argv[optind]);
> 
>      if (json_output)
>        fprintf (fp, "}\n");
> @@ -365,7 +366,7 @@ main (int argc, char *argv[])
>      exit (EXIT_FAILURE);
>    }
> 
> -  exit (EXIT_SUCCESS);
> +  exit (list_okay ? EXIT_SUCCESS : EXIT_FAILURE);
>  }
> 
>  static int
> @@ -398,7 +399,7 @@ collect_export (void *opaque, const char *name, const char *desc)
>    return 0;
>  }
> 
> -static void
> +static bool
>  list_one_export (struct nbd_handle *nbd, const char *desc,
>                   bool first, bool last)
>  {
> @@ -424,7 +425,7 @@ list_one_export (struct nbd_handle *nbd, const char *desc,
>        nbd_opt_go (nbd) == -1) {
>      fprintf (stderr, "%s: %s: %s\n", progname, nbd_get_export_name (nbd),
>               nbd_get_error ());
> -    return;
> +    return false;
>    }
>    size = nbd_get_size (nbd);
>    if (size == -1) {
> @@ -599,12 +600,14 @@ list_one_export (struct nbd_handle *nbd, const char *desc,
>    free (content);
>    free (export_name);
>    free (export_desc);
> +  return true;
>  }
> 
> -static void
> +static bool
>  list_all_exports (struct nbd_handle *nbd1, const char *uri)
>  {
>    size_t i;
> +  bool list_okay = true;
> 
>    if (export_list.size == 0 && json_output)
>      fprintf (fp, "\"exports\": []\n");
> @@ -639,14 +642,16 @@ list_all_exports (struct nbd_handle *nbd1, const char *uri)
>      }
> 
>      /* List the metadata of this export. */
> -    list_one_export (nbd2, export_list.ptr[i].desc, i == 0,
> -                     i + 1 == export_list.size);
> +    if (!list_one_export (nbd2, export_list.ptr[i].desc, i == 0,
> +                          i + 1 == export_list.size))
> +      list_okay = false;
> 
>      if (probe_content) {
>        nbd_shutdown (nbd2, 0);
>        nbd_close (nbd2);
>      }
>    }
> +  return list_okay;
>  }
> 
>  static void
> -- 
> 2.30.1

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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