[Libguestfs] [nbdkit PATCH 3/4] plugins: Make plugin_name() reliable past unload

[Eric Blake]

Directly returning storage in the module is risky, because it
forces callers to strdup() if they aren't sure of the lifetime.
Copying into the heap up front means that plugin_name() can
now be safely used even if unload happens in the meantime.

As long as we have only a single plugin in static storage (see
TODO), we don't need to free the copy.

Signed-off-by: Eric Blake <eblake at redhat.com>
---
 src/plugins.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/plugins.c b/src/plugins.c
index f5056d9..e8c6b28 100644
--- a/src/plugins.c
+++ b/src/plugins.c
@@ -143,6 +143,12 @@ plugin_register (const char *_filename,
       exit (EXIT_FAILURE);
     }
   }
+  /* Copy the module's name into local storage, so that plugin.name
+   * survives past unload. */
+  if (!(plugin.name = strdup (plugin.name))) {
+    perror ("strdup");
+    exit (EXIT_FAILURE);
+  }

   debug ("registered %s (name %s)", filename, plugin.name);

@@ -177,8 +183,6 @@ plugin_cleanup (void)
 const char *
 plugin_name (void)
 {
-  assert (dl);
-
   return plugin.name;
 }

-- 
2.13.6