scd: Add an re-select mechanism to switch apps.

* scd/app-common.h (struct app_ctx_s): Add func ptr 'reselect'.
* scd/app-piv.c (do_reselect): New.
(app_select_piv): Move AID constant to file scope.
* scd/app-openpgp.c (do_reselect): New.
(app_select_openpgp): Move AID constant to file scope.
* scd/app.c (apptype_from_name): New.
(check_application_conflict): Check against all apps of the card.
Always set current_apptype.
(select_additional_application): New.
(maybe_switch_app): New.
(app_write_learn_status, app_readcert, app_readkey, app_getattr)
(app_setattr, app_sign, app_auth, app_decipher, app_writecert)
(app_writekey, app_genkey, app_change_pin, app_check_pin): Use it here.
(app_do_with_keygrip): Force reselect on success.
(app_new_register): Move setting of CURRENT_APPTYPE to ...
(select_application): here so that it will be set to the requested
card.
* scd/command.c (open_card_with_request): Select additional
application if possible.
--

Noet that we will likely need to rework this even more so to get well
defined semantics for card access.

Signed-off-by: Werner Koch <[email protected]>

1 files changed, 9 insertions, 3 deletions

diff --git a/scd/command.c b/scd/command.c
index 3156aa9ef..2b851c5fd 100644
--- a/scd/command.c
+++ b/scd/command.c
@@ -231,9 +231,16 @@ open_card_with_request (ctrl_t ctrl,
   /* If we are already initialized for one specific application we
      need to check that the client didn't requested a specific
      application different from the one in use before we continue. */
-  /* FIXME: Extend to allow switching between apps.  */
   if (apptypestr && ctrl->card_ctx)
-    return check_application_conflict (ctrl->card_ctx, apptypestr);
+    {
+      err = check_application_conflict (ctrl->card_ctx, apptypestr);
+      if (gpg_err_code (err) == GPG_ERR_FALSE)
+        {
+          /* Different application but switching is supported.  */
+          err = select_additional_application (ctrl, apptypestr);
+        }
+      return err;
+    }
 
   /* Re-scan USB devices.  Release CARD, before the scan.  */
   /* FIXME: Is a card_unref sufficient or do we need to deallocate?  */
@@ -2084,7 +2091,6 @@ scd_clear_current_app (card_t card)
     }
 }
 
-
 /* Send a line with status information via assuan and escape all given
    buffers. The variable elements are pairs of (char *, size_t),
    terminated with a (NULL, 0). */