scd: Add option --multi to the LEARN command.

* scd/app-common.h (APP_LEARN_FLAG_MULTI): New.
* scd/command.c (cmd_learn): Add option --multi.
* scd/app.c (app_write_learn_status): Factor some code out to ...
(write_learn_status_core): new.
(app_write_learn_status): Implement flag --multi.
--

This new option is intended to return information about all active
applications of the current card.  Thus if a "SERIALNO openpgp" and a
"SERIALNO piv" has been done in a session the command "LEARN --force
--multi" returns information about both applications.

Signed-off-by: Werner Koch <wk@gnupg.org>

scd/app-common.h

@@ -44,6 +44,8 @@
 
 /* Flags used by the app_write_learn_status.  */
 #define APP_LEARN_FLAG_KEYPAIRINFO  1 /* Return only keypair infos.  */
+#define APP_LEARN_FLAG_MULTI        2 /* Return info for all apps.  */
+
 
 /* List of supported card types.  Generic is the usual ISO7817-4
  * compliant card.  More specific card or token versions can be given

scd/app.c

@@ -1030,13 +1030,36 @@ maybe_switch_app (ctrl_t ctrl, card_t card)
 }
 
 
+/* Helper for app_write_learn_status.  */
+static gpg_error_t
+write_learn_status_core (card_t card, app_t app, ctrl_t ctrl,
+                         unsigned int flags)
+{
+  /* We do not send CARD and APPTYPE if only keypairinfo is requested.  */
+  if (!(flags & APP_LEARN_FLAG_KEYPAIRINFO))
+    {
+      if (card && card->cardtype)
+        send_status_direct (ctrl, "CARDTYPE", strcardtype (card->cardtype));
+      if (card && card->cardversion)
+        send_status_printf (ctrl, "CARDVERSION", "%X", card->cardversion);
+      if (app->apptype)
+        send_status_direct (ctrl, "APPTYPE", strapptype (app->apptype));
+      if (app->appversion)
+        send_status_printf (ctrl, "APPVERSION", "%X", app->appversion);
+    }
+
+  return app->fnc.learn_status (app, ctrl, flags);
+}
+
+
 /* Write out the application specific status lines for the LEARN
    command. */
 gpg_error_t
 app_write_learn_status (card_t card, ctrl_t ctrl, unsigned int flags)
 {
-  gpg_error_t err;
+  gpg_error_t err, err2;
   app_t app;
+  int any_reselect = 0;
 
   if (!card)
     return gpg_error (GPG_ERR_INV_VALUE);
@@ -1045,29 +1068,43 @@ app_write_learn_status (card_t card, ctrl_t ctrl, unsigned int flags)
   if (err)
     return err;
 
+  /* Always make sure that the current app for this connection has
+   * been selected and is at the top of the list.  */
   if ((err = maybe_switch_app (ctrl, card)))
     ;
   else if (!card->app->fnc.learn_status)
     err = gpg_error (GPG_ERR_UNSUPPORTED_OPERATION);
   else
     {
-      app = card->app;
+      err = write_learn_status_core (card, card->app, ctrl, flags);
-
+      if (!err && card->app->fnc.reselect && (flags & APP_LEARN_FLAG_MULTI))
-      /* We do not send CARD and APPTYPE if only keypairinfo is requested.  */
-      if (!(flags & APP_LEARN_FLAG_KEYPAIRINFO))
         {
-          if (card->cardtype)
+          /* The current app has the reselect feature so that we can
-            send_status_direct (ctrl, "CARDTYPE", strcardtype (card->cardtype));
+           * loop over all other apps which are capable of a reselect
-          if (card->cardversion)
+           * and finally reselect the first app again.  Note that we
-            send_status_printf (ctrl, "CARDVERSION", "%X", card->cardversion);
+           * did the learn for the currently selected card above.  */
-          if (app->apptype)
+          app = card->app;
-            send_status_direct (ctrl, "APPTYPE", strapptype (app->apptype));
+          for (app = app->next; app && !err; app = app->next)
-          if (app->appversion)
+            if (app->fnc.reselect)
-            send_status_printf (ctrl, "APPVERSION", "%X", app->appversion);
+              {
-          /* FIXME: Send info for the other active apps of the card?  */
+                any_reselect = 1;
+                err = app->fnc.reselect (app, ctrl);
+                if (!err)
+                  err = write_learn_status_core (NULL, app, ctrl, flags);
+              }
+          app = card->app;
+          if (any_reselect)
+            {
+              err2 = app->fnc.reselect (app, ctrl);
+              if (err2)
+                {
+                  log_error ("error re-selecting '%s': %s\n",
+                             strapptype(app->apptype), gpg_strerror (err2));
+                  if (!err)
+                    err = err2;
+                }
+            }
         }
-
-      err = app->fnc.learn_status (app, ctrl, flags);
     }
 
   unlock_card (card);

scd/command.c

@@ -338,7 +338,7 @@ cmd_serialno (assuan_context_t ctx, char *line)
 
 
 static const char hlp_learn[] =
-  "LEARN [--force] [--keypairinfo]\n"
+  "LEARN [--force] [--keypairinfo] [--multi]\n"
   "\n"
   "Learn all useful information of the currently inserted card.  When\n"
   "used without the force options, the command might do an INQUIRE\n"
@@ -366,7 +366,8 @@ static const char hlp_learn[] =
   "    PIV     = PIV card\n"
   "    NKS     = NetKey card\n"
   "\n"
-  "are implemented.  These strings are aliases for the AID\n"
+  "are implemented.  These strings are aliases for the AID.  With option\n"
+  "--multi information for all switchable apps are returned.\n"
   "\n"
   "  S KEYPAIRINFO <hexstring_with_keygrip> <hexstring_with_id> [<usage>]\n"
   "\n"
@@ -413,6 +414,7 @@ cmd_learn (assuan_context_t ctx, char *line)
   ctrl_t ctrl = assuan_get_pointer (ctx);
   int rc = 0;
   int only_keypairinfo = has_option (line, "--keypairinfo");
+  int opt_multi = has_option (line, "--multi");
 
   if ((rc = open_card (ctrl)))
     return rc;
@@ -477,7 +479,8 @@ cmd_learn (assuan_context_t ctx, char *line)
   if (!rc)
     rc = app_write_learn_status
       (ctrl->card_ctx, ctrl,
-       (only_keypairinfo? APP_LEARN_FLAG_KEYPAIRINFO : 0));
+       ( (only_keypairinfo? APP_LEARN_FLAG_KEYPAIRINFO : 0)
+         | (opt_multi? APP_LEARN_FLAG_MULTI : 0)) );
 
   return rc;
 }