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

[Eric Blake]

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>
---

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