New API: inspect-get-roots to return roots from last inspection.

Return the roots found by the last call to inspect-os, but
without redoing the whole inspection.

2 files changed, 47 insertions, 20 deletions

diff --git a/generator/generator_actions.ml b/generator/generator_actions.ml
index e7dd42b6..4d7a4b33 100644
--- a/generator/generator_actions.ml
+++ b/generator/generator_actions.ml
@@ -1038,6 +1038,19 @@ the case then an error is returned.
 
 Please read L<guestfs(3)/INSPECTION> for more details.");
 
+  ("inspect_get_roots", (RStringList "roots", [], []), -1, [],
+   [],
+   "return list of operating systems found by last inspection",
+   "\
+This function is a convenient way to get the list of root
+devices, as returned from a previous call to C<guestfs_inspect_os>,
+but without redoing the whole inspection process.
+
+This returns an empty list if either no root devices were
+found or the caller has not called C<guestfs_inspect_os>.
+
+Please read L<guestfs(3)/INSPECTION> for more details.");
+
 ]
 
 (* daemon_functions are any functions which cause some action
diff --git a/src/inspect.c b/src/inspect.c
index e7b1e413..b06c8f68 100644
--- a/src/inspect.c
+++ b/src/inspect.c
@@ -423,28 +423,11 @@ guestfs__inspect_os (guestfs_h *g)
   /* At this point we have, in the handle, a list of all filesystems
    * found and data about each one.  Now we assemble the list of
    * filesystems which are root devices and return that to the user.
+   * Fall through to guestfs__inspect_get_roots to do that.
    */
-  size_t count = 0;
-  for (i = 0; i < g->nr_fses; ++i)
-    if (g->fses[i].is_root)
-      count++;
-
-  char **ret = calloc (count+1, sizeof (char *));
-  if (ret == NULL) {
-    perrorf (g, "calloc");
+  char **ret = guestfs__inspect_get_roots (g);
+  if (ret == NULL)
     guestfs___free_inspect_info (g);
-    return NULL;
-  }
-
-  count = 0;
-  for (i = 0; i < g->nr_fses; ++i) {
-    if (g->fses[i].is_root) {
-      ret[count] = safe_strdup (g, g->fses[i].device);
-      count++;
-    }
-  }
-  ret[count] = NULL;
-
   return ret;
 }
 
@@ -1307,6 +1290,37 @@ search_for_root (guestfs_h *g, const char *root)
   return NULL;
 }
 
+char **
+guestfs__inspect_get_roots (guestfs_h *g)
+{
+  /* NB. Doesn't matter if g->nr_fses == 0.  We just return an empty
+   * list in this case.
+   */
+
+  size_t i;
+  size_t count = 0;
+  for (i = 0; i < g->nr_fses; ++i)
+    if (g->fses[i].is_root)
+      count++;
+
+  char **ret = calloc (count+1, sizeof (char *));
+  if (ret == NULL) {
+    perrorf (g, "calloc");
+    return NULL;
+  }
+
+  count = 0;
+  for (i = 0; i < g->nr_fses; ++i) {
+    if (g->fses[i].is_root) {
+      ret[count] = safe_strdup (g, g->fses[i].device);
+      count++;
+    }
+  }
+  ret[count] = NULL;
+
+  return ret;
+}
+
 char *
 guestfs__inspect_get_type (guestfs_h *g, const char *root)
 {