scd: Fix access to list of cards (3/3).

* scd/app-common.h (card_reset): Simplify more.
(select_additional_application): Supply CARD.
(card_ref, card_unref): Remove.
(card_get, card_put): New.
* scd/app.c (card_reset): No locking/unlocking inside.
(app_switch_current_card): Fix comment.
(select_additional_application): No locking/unlocking inside.
(do_with_keygrip): New, unlocked version.
(card_get): New, with support of KEYGRIP.
(card_unref): Remove.
(card_put): New.
(app_write_learn_status, app_readcert: No locking/unlocking inside.
(app_readkey, app_getattr, app_setattr, app_sign, app_auth): Likewise.
(app_decipher, app_writecert, app_writekey): Likewise.
(app_genkey, app_get_challenge, app_change_pin): Likewise.
(app_check_pin, app_switch_active_app): Likewise.
* scd/command.c (do_reset): Use card_get/card_put.
(open_card_with_request): Use card_get/card_put, return CARD locked.
(cmd_serialno): Follow the change of open_card_with_request.
(cmd_switchapp): Use card_get/card_put.
(cmd_learn, cmd_readcert, cmd_readkey, cmd_pksign): Likewise.
(cmd_pkauth, cmd_pkdecrypt, cmd_getattr): Likewise.
(cmd_setattr, cmd_writecert, cmd_writekey): Likewise.
(cmd_genkey, cmd_random, cmd_passwd): Likewise.
(cmd_checkpin, cmd_getinfo, cmd_restart): Likewise.
(cmd_disconnect, cmd_apdu, cmd_devinfo): Likewise.

Signed-off-by: NIIBE Yutaka <[email protected]>

3 files changed, 315 insertions, 315 deletions

diff --git a/scd/app-common.h b/scd/app-common.h
index d1b0a9a17..2eeffbe95 100644
--- a/scd/app-common.h
+++ b/scd/app-common.h
@@ -255,11 +255,12 @@ void application_notify_card_reset (int slot);
 gpg_error_t check_application_conflict (card_t card, const char *name,
                                         const unsigned char *serialno_bin,
                                         size_t serialno_bin_len);
-gpg_error_t card_reset (card_t card, ctrl_t ctrl);
+gpg_error_t card_reset (card_t card);
 gpg_error_t select_application (ctrl_t ctrl, const char *name,
                                 int scan, const unsigned char *serialno_bin,
                                 size_t serialno_bin_len);
-gpg_error_t select_additional_application (ctrl_t ctrl, const char *name);
+gpg_error_t select_additional_application (card_t card,
+                                           ctrl_t ctrl, const char *name);
 
 gpg_error_t app_switch_current_card (ctrl_t ctrl,
                                      const unsigned char *serialno,
@@ -269,8 +270,8 @@ gpg_error_t app_switch_active_app (card_t card, ctrl_t ctrl,
 
 char *get_supported_applications (void);
 
-card_t card_ref (card_t card);
-void   card_unref (card_t card);
+card_t card_get (ctrl_t ctrl, const char *keygrip);
+void card_put (card_t card);
 void   card_unref_locked (card_t card);
 
 gpg_error_t app_munge_serialno (card_t card);
diff --git a/scd/app.c b/scd/app.c
index 1b5bfad53..a86b08cd2 100644
--- a/scd/app.c
+++ b/scd/app.c
@@ -503,18 +503,16 @@ check_application_conflict (card_t card, const char *name,
 
 
 gpg_error_t
-card_reset (card_t card, ctrl_t ctrl)
+card_reset (card_t card)
 {
   gpg_error_t err = 0;
   int sw;
 
-  lock_card (card, ctrl);
   sw = apdu_reset (card->slot);
   if (sw)
     err = gpg_error (GPG_ERR_CARD_RESET);
 
   card->reset_requested = 1;
-  unlock_card (card);
   scd_kick_the_loop ();
   gnupg_sleep (1);
 
@@ -862,7 +860,6 @@ select_application (ctrl_t ctrl, const char *name,
 
       if (!err)
         {
-          /* Note: We do not use card_ref as we are already locked.  */
           card->ref_count++;
           ctrl->card_ctx = card;
           if (card_prev)
@@ -895,7 +892,8 @@ app_switch_current_card (ctrl_t ctrl,
 
   lock_r_card_list ();
 
-  if (!ctrl->card_ctx)
+  cardtmp = ctrl->card_ctx;
+  if (!cardtmp)
     {
       err = gpg_error (GPG_ERR_CARD_NOT_INITIALIZED);
       goto leave;
@@ -915,10 +913,10 @@ app_switch_current_card (ctrl_t ctrl,
           goto leave;
         }
 
-      /* Note: We do not use card_ref here because we only swap the
-       * context of the current session and there is no chance of a
-       * context switch.  This also works if the card stays the same. */
-      cardtmp = ctrl->card_ctx;
+      /* Note: We do not lock CARD and CARDTMP here because we only
+       * swap the context of the current session and there is no
+       * chance of a context switch.  This also works if the card
+       * stays the same.  */
       ctrl->card_ctx = card;
       card->ref_count++;
       card_unref_locked (cardtmp);
@@ -1077,11 +1075,10 @@ select_all_additional_applications_internal (ctrl_t ctrl, card_t card)
  * active application.  On error no new application is allocated.
  * Selecting an already selected application has no effect. */
 gpg_error_t
-select_additional_application (ctrl_t ctrl, const char *name)
+select_additional_application (card_t card, ctrl_t ctrl, const char *name)
 {
   gpg_error_t err = 0;
   apptype_t req_apptype;
-  card_t card;
 
   if (!name)
     req_apptype = 0;
@@ -1092,14 +1089,6 @@ select_additional_application (ctrl_t ctrl, const char *name)
         return gpg_error (GPG_ERR_NOT_FOUND);
     }
 
-  card = ctrl->card_ctx;
-  if (!card)
-    return gpg_error (GPG_ERR_CARD_NOT_INITIALIZED);
-
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
-
   if (req_apptype)
     {
       err = select_additional_application_internal (card, req_apptype);
@@ -1115,7 +1104,6 @@ select_additional_application (ctrl_t ctrl, const char *name)
       err = select_all_additional_applications_internal (ctrl, card);
     }
 
-  unlock_card (card);
   return err;
 }
 
@@ -1183,35 +1171,104 @@ deallocate_card (card_t card)
 }
 
 
-/* Increment the reference counter of CARD.  Returns CARD.  */
+static card_t
+do_with_keygrip (ctrl_t ctrl, int action, const char *keygrip_str,
+                 int capability)
+{
+  int locked = 0;
+  card_t c;
+  app_t a, a_prev;
+
+  for (c = card_top; c; c = c->next)
+    {
+      if (lock_card (c, ctrl))
+        {
+          c = NULL;
+          goto leave_the_loop;
+        }
+      locked = 1;
+      a_prev = NULL;
+      for (a = c->app; a; a = a->next)
+        {
+          if (!a->fnc.with_keygrip || a->need_reset)
+            continue;
+
+          /* Note that we need to do a re-select even for the current
+           * app because the last selected application (e.g. after
+           * init) might be a different one and we do not run
+           * maybe_switch_app here.  Of course we we do this only iff
+           * we have an additional app. */
+          if (c->app->next)
+            {
+              if (run_reselect (ctrl, c, a, a_prev))
+                continue;
+            }
+          a_prev = a;
+
+          if (DBG_APP)
+            log_debug ("slot %d, app %s: calling with_keygrip(%s)\n",
+                       c->slot, xstrapptype (a),
+                       action == KEYGRIP_ACTION_SEND_DATA? "send_data":
+                       action == KEYGRIP_ACTION_WRITE_STATUS? "status":
+                       action == KEYGRIP_ACTION_LOOKUP? "lookup":"?");
+          if (!a->fnc.with_keygrip (a, ctrl, action, keygrip_str, capability))
+            goto leave_the_loop; /* ACTION_LOOKUP succeeded.  */
+        }
+
+      /* Select the first app again.  */
+      if (c->app->next)
+        run_reselect (ctrl, c, c->app, a_prev);
+
+      unlock_card (c);
+      locked = 0;
+    }
+
+ leave_the_loop:
+  /* Force switching of the app if the selected one is not the current
+   * one.  Changing the current apptype is sufficient to do this.  */
+  if (c && c->app && c->app->apptype != a->apptype)
+    ctrl->current_apptype = a->apptype;
+
+  if (locked && c)
+    {
+      unlock_card (c);
+      locked = 0;
+    }
+  return c;
+}
+
+
+/* Locking access to the card-list and CARD, returns CARD.  */
 card_t
-card_ref (card_t card)
+card_get (ctrl_t ctrl, const char *keygrip)
 {
+  card_t card;
+
+  lock_r_card_list ();
+  if (keygrip)
+    card = do_with_keygrip (ctrl, KEYGRIP_ACTION_LOOKUP, keygrip, 0);
+  else
+    card = ctrl->card_ctx;
+  if (!card)
+    {
+      unlock_r_card_list ();
+      return NULL;
+    }
+
   lock_card (card, NULL);
-  ++card->ref_count;
-  unlock_card (card);
   return card;
 }
 
-
-/* Decrement the reference counter for CARD.  Note that we are using
- * reference counting to track the users of the card's application and
- * are deferring the actual deallocation to allow for a later reuse by
- * a new connection.  Using NULL for CARD is a no-op. */
+/* Release the lock of CARD and the card-list.  */
 void
-card_unref (card_t card)
+card_put (card_t card)
 {
-  if (!card)
-    return;
-
   /* We don't deallocate CARD here.  Instead, we keep it.  This is
      useful so that a card does not get reset even if only one session
      is using the card - this way the PIN cache and other cached data
      are preserved.  */
-
-  lock_card (card, NULL);
-  card_unref_locked (card);
   unlock_card (card);
+  unlock_r_card_list ();
 }
 
 
@@ -1698,13 +1755,6 @@ app_write_learn_status (card_t card, ctrl_t ctrl, unsigned int flags)
   app_t app, last_app;
   int any_reselect = 0;
 
-  if (!card)
-    return gpg_error (GPG_ERR_INV_VALUE);
-
-  err = lock_card (card, ctrl);
-  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, NULL)))
@@ -1766,7 +1816,6 @@ app_write_learn_status (card_t card, ctrl_t ctrl, unsigned int flags)
         }
     }
 
-  unlock_card (card);
   return err;
 }
 
@@ -1781,12 +1830,6 @@ app_readcert (card_t card, ctrl_t ctrl, const char *certid,
 {
   gpg_error_t err;
 
-  if (!card)
-    return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
-
   if ((err = maybe_switch_app (ctrl, card, certid)))
     ;
   else if (!card->app->fnc.readcert)
@@ -1802,7 +1845,6 @@ app_readcert (card_t card, ctrl_t ctrl, const char *certid,
         err = card->app->fnc.readcert (card->app, certid, cert, certlen);
     }
 
-  unlock_card (card);
   return err;
 }
 
@@ -1826,11 +1868,8 @@ app_readkey (card_t card, ctrl_t ctrl, const char *keyid, unsigned int flags,
   if (pklen)
     *pklen = 0;
 
-  if (!card || !keyid)
+  if (!keyid)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if ((err = maybe_switch_app (ctrl, card, keyid)))
     ;
@@ -1847,7 +1886,6 @@ app_readkey (card_t card, ctrl_t ctrl, const char *keyid, unsigned int flags,
         err = card->app->fnc.readkey (card->app, ctrl, keyid, flags, pk, pklen);
     }
 
-  unlock_card (card);
   return err;
 }
 
@@ -1858,11 +1896,8 @@ app_getattr (card_t card, ctrl_t ctrl, const char *name)
 {
   gpg_error_t err;
 
-  if (!card || !name || !*name)
+  if (!name || !*name)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if ((err = maybe_switch_app (ctrl, card, NULL)))
     ;
@@ -1900,7 +1935,6 @@ app_getattr (card_t card, ctrl_t ctrl, const char *name)
         err = card->app->fnc.getattr (card->app, ctrl, name);
     }
 
-  unlock_card (card);
   return err;
 }
 
@@ -1914,11 +1948,8 @@ app_setattr (card_t card, ctrl_t ctrl, const char *name,
 {
   gpg_error_t err;
 
-  if (!card || !name || !*name || !value)
+  if (!name || !*name || !value)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if ((err = maybe_switch_app (ctrl, card, NULL)))
     ;
@@ -1936,7 +1967,6 @@ app_setattr (card_t card, ctrl_t ctrl, const char *name,
                                       value, valuelen);
     }
 
-  unlock_card (card);
   return err;
 }
 
@@ -1953,11 +1983,8 @@ app_sign (card_t card, ctrl_t ctrl, const char *keyidstr, int hashalgo,
 {
   gpg_error_t err;
 
-  if (!card || !indata || !indatalen || !outdata || !outdatalen || !pincb)
+  if (!indata || !indatalen || !outdata || !outdatalen || !pincb)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if ((err = maybe_switch_app (ctrl, card, keyidstr)))
     ;
@@ -1977,7 +2004,6 @@ app_sign (card_t card, ctrl_t ctrl, const char *keyidstr, int hashalgo,
                                    outdata, outdatalen);
     }
 
-  unlock_card (card);
   if (opt.verbose)
     log_info ("operation sign result: %s\n", gpg_strerror (err));
   return err;
@@ -1997,11 +2023,8 @@ app_auth (card_t card, ctrl_t ctrl, const char *keyidstr,
 {
   gpg_error_t err;
 
-  if (!card || !indata || !indatalen || !outdata || !outdatalen || !pincb)
+  if (!indata || !indatalen || !outdata || !outdatalen || !pincb)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if ((err = maybe_switch_app (ctrl, card, keyidstr)))
     ;
@@ -2021,7 +2044,6 @@ app_auth (card_t card, ctrl_t ctrl, const char *keyidstr,
                                    outdata, outdatalen);
     }
 
-  unlock_card (card);
   if (opt.verbose)
     log_info ("operation auth result: %s\n", gpg_strerror (err));
   return err;
@@ -2043,11 +2065,8 @@ app_decipher (card_t card, ctrl_t ctrl, const char *keyidstr,
 
   *r_info = 0;
 
-  if (!card || !indata || !indatalen || !outdata || !outdatalen || !pincb)
+  if (!indata || !indatalen || !outdata || !outdatalen || !pincb)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if ((err = maybe_switch_app (ctrl, card, keyidstr)))
     ;
@@ -2068,7 +2087,6 @@ app_decipher (card_t card, ctrl_t ctrl, const char *keyidstr,
                                        r_info);
     }
 
-  unlock_card (card);
   if (opt.verbose)
     log_info ("operation decipher result: %s\n", gpg_strerror (err));
   return err;
@@ -2085,11 +2103,8 @@ app_writecert (card_t card, ctrl_t ctrl,
 {
   gpg_error_t err;
 
-  if (!card || !certidstr || !*certidstr || !pincb)
+  if (!certidstr || !*certidstr || !pincb)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if ((err = maybe_switch_app (ctrl, card, certidstr)))
     ;
@@ -2107,7 +2122,6 @@ app_writecert (card_t card, ctrl_t ctrl,
                                         pincb, pincb_arg, data, datalen);
     }
 
-  unlock_card (card);
   if (opt.verbose)
     log_info ("operation writecert result: %s\n", gpg_strerror (err));
   return err;
@@ -2124,11 +2138,8 @@ app_writekey (card_t card, ctrl_t ctrl,
 {
   gpg_error_t err;
 
-  if (!card || !keyidstr || !*keyidstr || !pincb)
+  if (!keyidstr || !*keyidstr || !pincb)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if ((err = maybe_switch_app (ctrl, card, keyidstr)))
     ;
@@ -2146,7 +2157,6 @@ app_writekey (card_t card, ctrl_t ctrl,
                                        pincb, pincb_arg, keydata, keydatalen);
     }
 
-  unlock_card (card);
   if (opt.verbose)
     log_info ("operation writekey result: %s\n", gpg_strerror (err));
   return err;
@@ -2162,11 +2172,8 @@ app_genkey (card_t card, ctrl_t ctrl, const char *keynostr,
 {
   gpg_error_t err;
 
-  if (!card || !keynostr || !*keynostr || !pincb)
+  if (!keynostr || !*keynostr || !pincb)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if ((err = maybe_switch_app (ctrl, card, keynostr)))
     ;
@@ -2184,7 +2191,6 @@ app_genkey (card_t card, ctrl_t ctrl, const char *keynostr,
                                      createtime, pincb, pincb_arg);
     }
 
-  unlock_card (card);
   if (opt.verbose)
     log_info ("operation genkey result: %s\n", gpg_strerror (err));
   return err;
@@ -2200,18 +2206,15 @@ app_get_challenge (card_t card, ctrl_t ctrl,
 {
   gpg_error_t err;
 
-  if (!card || !nbytes || !buffer)
+  (void)ctrl;
+  if (!nbytes || !buffer)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if (!card->ref_count)
     err = gpg_error (GPG_ERR_CARD_NOT_INITIALIZED);
   else
     err = iso7816_get_challenge (card->slot, nbytes, buffer);
 
-  unlock_card (card);
   return err;
 }
 
@@ -2225,11 +2228,8 @@ app_change_pin (card_t card, ctrl_t ctrl, const char *chvnostr,
 {
   gpg_error_t err;
 
-  if (!card || !chvnostr || !*chvnostr || !pincb)
+  if (!chvnostr || !*chvnostr || !pincb)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if ((err = maybe_switch_app (ctrl, card, NULL)))
     ;
@@ -2247,7 +2247,6 @@ app_change_pin (card_t card, ctrl_t ctrl, const char *chvnostr,
                                          chvnostr, flags, pincb, pincb_arg);
     }
 
-  unlock_card (card);
   if (opt.verbose)
     log_info ("operation change_pin result: %s\n", gpg_strerror (err));
   return err;
@@ -2264,11 +2263,8 @@ app_check_pin (card_t card, ctrl_t ctrl, const char *keyidstr,
 {
   gpg_error_t err;
 
-  if (!card || !keyidstr || !*keyidstr || !pincb)
+  if (!keyidstr || !*keyidstr || !pincb)
     return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
 
   if ((err = maybe_switch_app (ctrl, card, NULL)))
     ;
@@ -2286,7 +2282,6 @@ app_check_pin (card_t card, ctrl_t ctrl, const char *keyidstr,
                                         pincb, pincb_arg);
     }
 
-  unlock_card (card);
   if (opt.verbose)
     log_info ("operation check_pin result: %s\n", gpg_strerror (err));
   return err;
@@ -2616,12 +2611,6 @@ app_switch_active_app (card_t card, ctrl_t ctrl, const char *appname)
   gpg_error_t err;
   apptype_t apptype;
 
-  if (!card)
-    return gpg_error (GPG_ERR_INV_VALUE);
-  err = lock_card (card, ctrl);
-  if (err)
-    return err;
-
   /* Note that in case the additional applications have not yet been
    * added to the card context (which is commonly done by means of
    * "SERIALNO --all", we do that here.  */
@@ -2648,7 +2637,6 @@ app_switch_active_app (card_t card, ctrl_t ctrl, const char *appname)
   err = send_serialno_and_app_status (card, 1, ctrl);
 
  leave:
-  unlock_card (card);
   return err;
 }
 
@@ -2682,69 +2670,12 @@ card_t
 app_do_with_keygrip (ctrl_t ctrl, int action, const char *keygrip_str,
                      int capability)
 {
-  int locked = 0;
-  card_t c;
-  app_t a, a_prev;
+  card_t card;
 
   lock_r_card_list ();
-
-  for (c = card_top; c; c = c->next)
-    {
-      if (lock_card (c, ctrl))
-        {
-          c = NULL;
-          goto leave_the_loop;
-        }
-      locked = 1;
-      a_prev = NULL;
-      for (a = c->app; a; a = a->next)
-        {
-          if (!a->fnc.with_keygrip || a->need_reset)
-            continue;
-
-          /* Note that we need to do a re-select even for the current
-           * app because the last selected application (e.g. after
-           * init) might be a different one and we do not run
-           * maybe_switch_app here.  Of course we we do this only iff
-           * we have an additional app. */
-          if (c->app->next)
-            {
-              if (run_reselect (ctrl, c, a, a_prev))
-                continue;
-            }
-          a_prev = a;
-
-          if (DBG_APP)
-            log_debug ("slot %d, app %s: calling with_keygrip(%s)\n",
-                       c->slot, xstrapptype (a),
-                       action == KEYGRIP_ACTION_SEND_DATA? "send_data":
-                       action == KEYGRIP_ACTION_WRITE_STATUS? "status":
-                       action == KEYGRIP_ACTION_LOOKUP? "lookup":"?");
-          if (!a->fnc.with_keygrip (a, ctrl, action, keygrip_str, capability))
-            goto leave_the_loop; /* ACTION_LOOKUP succeeded.  */
-        }
-
-      /* Select the first app again.  */
-      if (c->app->next)
-        run_reselect (ctrl, c, c->app, a_prev);
-
-      unlock_card (c);
-      locked = 0;
-    }
-
- leave_the_loop:
-  /* Force switching of the app if the selected one is not the current
-   * one.  Changing the current apptype is sufficient to do this.  */
-  if (c && c->app && c->app->apptype != a->apptype)
-    ctrl->current_apptype = a->apptype;
-
-  if (locked && c)
-    {
-      unlock_card (c);
-      locked = 0;
-    }
+  card = do_with_keygrip (ctrl, action, keygrip_str, capability);
   unlock_r_card_list ();
-  return c;
+  return card;
 }
 
 void
diff --git a/scd/command.c b/scd/command.c
index d45d9da82..5ba71a4aa 100644
--- a/scd/command.c
+++ b/scd/command.c
@@ -154,18 +154,19 @@ hex_to_buffer (const char *string, size_t *r_length)
 static void
 do_reset (ctrl_t ctrl, int send_reset, int keep_lock)
 {
-  card_t card = ctrl->card_ctx;
+  card_t card = card_get (ctrl, NULL);
 
   if (card)
     {
       if (!IS_LOCKED (ctrl) && send_reset)
-        card_reset (card, ctrl);
+        card_reset (card);
       else
         {
           ctrl->card_ctx = NULL;
           ctrl->current_apptype = APPTYPE_NONE;
-          card_unref (card);
+          card_unref_locked (card);
         }
+      card_put (card);
     }
 
   /* If we hold a lock, unlock now. */
@@ -238,14 +239,14 @@ open_card (ctrl_t ctrl)
 /* Explicitly open a card for a specific use of APPTYPE or SERIALNO.
  * If OPT_ALL is set also add all possible additional apps. */
 static gpg_error_t
-open_card_with_request (ctrl_t ctrl,
+open_card_with_request (card_t *card_p, ctrl_t ctrl,
                         const char *apptypestr, const char *serialno,
                         int opt_all)
 {
   gpg_error_t err;
   unsigned char *serialno_bin = NULL;
   size_t serialno_bin_len = 0;
-  card_t card = ctrl->card_ctx;
+  card_t card = card_get (ctrl, NULL);
 
   if (serialno)
     serialno_bin = hex_to_buffer (serialno, &serialno_bin_len);
@@ -253,30 +254,45 @@ 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. */
-  if (apptypestr && ctrl->card_ctx)
+  if (apptypestr && card)
     {
-      err = check_application_conflict (ctrl->card_ctx, apptypestr,
+      err = check_application_conflict (card, apptypestr,
                                         serialno_bin, serialno_bin_len);
       if (gpg_err_code (err) == GPG_ERR_FALSE)
         {
           /* Different application but switching is supported.  */
-          err = select_additional_application (ctrl, apptypestr);
+          err = select_additional_application (card, ctrl, apptypestr);
         }
+      if (err)
+	card_put (card);
       goto leave;
     }
 
   /* Re-scan USB devices.  Release CARD, before the scan.  */
-  /* FIXME: Is a card_unref sufficient or do we need to deallocate?  */
-  ctrl->card_ctx = NULL;
-  ctrl->current_apptype = APPTYPE_NONE;
-  card_unref (card);
+  if (card)
+    {
+      ctrl->card_ctx = NULL;
+      ctrl->current_apptype = APPTYPE_NONE;
+      card_unref_locked (card);
+      card_put (card);
+    }
 
   err = select_application (ctrl, apptypestr, 1,
                             serialno_bin, serialno_bin_len);
+  card = card_get (ctrl, NULL);
   if (!err && opt_all)
-    err = select_additional_application (ctrl, NULL);
+    {
+      if (card)
+        {
+          err = select_additional_application (card, ctrl, NULL);
+	  if (err)
+	    card_put (card);
+        }
+    }
 
  leave:
+  if (!err)
+    *card_p = card;
   xfree (serialno_bin);
   return err;
 }
@@ -311,10 +327,11 @@ cmd_serialno (assuan_context_t ctx, char *line)
 {
   ctrl_t ctrl = assuan_get_pointer (ctx);
   struct server_local_s *sl;
-  int rc = 0;
+  gpg_error_t err = 0;
   char *serial;
   const char *demand;
   int opt_all = has_option (line, "--all");
+  card_t card = NULL;
   int thisslot;
 
   if ( IS_LOCKED (ctrl) )
@@ -337,30 +354,31 @@ cmd_serialno (assuan_context_t ctx, char *line)
 
   /* Clear the remove flag so that the open_card is able to reread it.  */
   ctrl->server_local->card_removed = 0;
-  rc = open_card_with_request (ctrl, *line? line:NULL, demand, opt_all);
+  err = open_card_with_request (&card, ctrl, *line? line:NULL, demand, opt_all);
   /* Now clear or set the card_removed flag for all sessions using the
    * current slot.  In the error case make sure that the flag is set
    * for the current session. */
-  thisslot = ctrl->card_ctx? ctrl->card_ctx->slot : -1;
+  thisslot = card? card->slot : -1;
   for (sl=session_list; sl; sl = sl->next_session)
     {
       ctrl_t c = sl->ctrl_backlink;
       if (c && c->card_ctx && c->card_ctx->slot == thisslot)
-        c->server_local->card_removed = rc? 1 : 0;
+        c->server_local->card_removed = err? 1 : 0;
     }
-  if (rc)
+  if (err)
     {
       ctrl->server_local->card_removed = 1;
-      return rc;
+      return err;
     }
 
-  serial = card_get_serialno (ctrl->card_ctx);
+  serial = card_get_serialno (card);
+  card_put (card);
   if (!serial)
     return gpg_error (GPG_ERR_INV_VALUE);
 
-  rc = assuan_write_status (ctx, "SERIALNO", serial);
+  err = assuan_write_status (ctx, "SERIALNO", serial);
   xfree (serial);
-  return rc;
+  return err;
 }
 
 
@@ -419,12 +437,22 @@ cmd_switchapp (assuan_context_t ctx, char *line)
 {
   ctrl_t ctrl = assuan_get_pointer (ctx);
   gpg_error_t err = 0;
+  card_t card;
 
   if ((err = open_card (ctrl)))
     return err;
 
   line = skip_options (line);
-  return app_switch_active_app (ctrl->card_ctx, ctrl, line);
+  card = card_get (ctrl, NULL);
+  if (card)
+    {
+      err = app_switch_active_app (card, ctrl, line);
+      card_put (card);
+    }
+  else
+    err = gpg_error (GPG_ERR_CARD_NOT_PRESENT);
+
+  return err;
 }
 
 
@@ -510,10 +538,15 @@ cmd_learn (assuan_context_t ctx, char *line)
   int opt_multi = has_option (line, "--multi");
   int opt_reread = has_option (line, "--reread");
   unsigned int flags;
+  card_t card;
 
   if ((rc = open_card (ctrl)))
     return rc;
 
+  card = card_get (ctrl, NULL);
+  if (!card)
+    return gpg_error (GPG_ERR_CARD_NOT_PRESENT);
+
   /* Unless the force option is used we try a shortcut by identifying
      the card using a serial number and inquiring the client with
      that. The client may choose to cancel the operation if he already
@@ -522,25 +555,28 @@ cmd_learn (assuan_context_t ctx, char *line)
     {
       const char *reader;
       char *serial;
-      card_t card = ctrl->card_ctx;
-
-      if (!card)
-        return gpg_error (GPG_ERR_CARD_NOT_PRESENT);
 
       reader = apdu_get_reader_name (card->slot);
       if (!reader)
-        return out_of_core ();
+        {
+          card_put (card);
+          return out_of_core ();
+        }
       send_status_direct (ctrl, "READER", reader);
       /* No need to free the string of READER.  */
 
-      serial = card_get_serialno (ctrl->card_ctx);
+      serial = card_get_serialno (card);
       if (!serial)
-        return gpg_error (GPG_ERR_INV_VALUE);
+        {
+          card_put (card);
+          return gpg_error (GPG_ERR_INV_VALUE);
+        }
 
       rc = assuan_write_status (ctx, "SERIALNO", serial);
       if (rc < 0)
         {
           xfree (serial);
+          card_put (card);
           return out_of_core ();
         }
 
@@ -552,6 +588,7 @@ cmd_learn (assuan_context_t ctx, char *line)
           if (rc < 0)
             {
               xfree (serial);
+              card_put (card);
               return out_of_core ();
             }
           rc = assuan_inquire (ctx, command, NULL, NULL, 0);
@@ -562,6 +599,7 @@ cmd_learn (assuan_context_t ctx, char *line)
                 log_error ("inquire KNOWNCARDP failed: %s\n",
                            gpg_strerror (rc));
               xfree (serial);
+              card_put (card);
               return rc;
             }
           /* Not canceled, so we have to proceed.  */
@@ -580,8 +618,9 @@ cmd_learn (assuan_context_t ctx, char *line)
     flags |= APP_LEARN_FLAG_REREAD;
 
   if (!rc)
-    rc = app_write_learn_status (ctrl->card_ctx, ctrl, flags);
+    rc = app_write_learn_status (card, ctrl, flags);
 
+  card_put (card);
   return rc;
 }
 
@@ -598,6 +637,7 @@ cmd_readcert (assuan_context_t ctx, char *line)
   int rc;
   unsigned char *cert;
   size_t ncert;
+  card_t card;
 
   if ((rc = open_card (ctrl)))
     return rc;
@@ -606,9 +646,17 @@ cmd_readcert (assuan_context_t ctx, char *line)
   if (!line)
     return gpg_error_from_syserror ();
 
-  rc = app_readcert (ctrl->card_ctx, ctrl, line, &cert, &ncert);
+  card = card_get (ctrl, NULL);
+  if (!card)
+    {
+      xfree (line);
+      return gpg_error (GPG_ERR_CARD_NOT_PRESENT);
+    }
+
+  rc = app_readcert (card, ctrl, line, &cert, &ncert);
   if (rc)
     log_error ("app_readcert failed: %s\n", gpg_strerror (rc));
+  card_put (card);
   xfree (line);
   line = NULL;
   if (!rc)
@@ -708,7 +756,7 @@ cmd_readkey (assuan_context_t ctx, char *line)
   unsigned char *pk = NULL;
   size_t pklen;
   card_t card;
-  int direct = 0;
+  const char *keygrip = NULL;
 
   if ((rc = open_card (ctrl)))
     return rc;
@@ -727,22 +775,13 @@ cmd_readkey (assuan_context_t ctx, char *line)
     return gpg_error_from_syserror ();
 
   if (strlen (line) == 40)
-    {
-      card = app_do_with_keygrip (ctrl, KEYGRIP_ACTION_LOOKUP, line, 0);
-      direct = 1;
-    }
-  else
-    card = ctrl->card_ctx;
+    keygrip = line;
 
+  card = card_get (ctrl, keygrip);
   if (card)
     {
-      if (direct)
-        card_ref (card);
-
       rc = do_readkey (card, ctrl, line, opt_info, &pk, &pklen);
-
-      if (direct)
-        card_unref (card);
+      card_put (card);
     }
   else
     rc = gpg_error (GPG_ERR_NO_SECKEY);
@@ -923,7 +962,7 @@ cmd_pksign (assuan_context_t ctx, char *line)
   char *keyidstr;
   int hash_algo;
   card_t card;
-  int direct = 0;
+  const char *keygrip = NULL;
 
   if (has_option (line, "--hash=rmd160"))
     hash_algo = GCRY_MD_RMD160;
@@ -961,24 +1000,17 @@ cmd_pksign (assuan_context_t ctx, char *line)
   /* When it's a keygrip, we directly use the card, with no change of
      ctrl->card_ctx. */
   if (strlen (keyidstr) == 40)
-    {
-      card = app_do_with_keygrip (ctrl, KEYGRIP_ACTION_LOOKUP, keyidstr, 0);
-      direct = 1;
-    }
-  else
-    card = ctrl->card_ctx;
+    keygrip = keyidstr;
 
+  card = card_get (ctrl, keygrip);
   if (card)
     {
-      if (direct)
-        card_ref (card);
       rc = app_sign (card, ctrl,
                      keyidstr, hash_algo,
                      pin_cb, ctx,
                      ctrl->in_data.value, ctrl->in_data.valuelen,
                      &outdata, &outdatalen);
-      if (direct)
-        card_unref (card);
+      card_put (card);
     }
   else
     rc = gpg_error (GPG_ERR_NO_SECKEY);
@@ -1011,14 +1043,11 @@ cmd_pkauth (assuan_context_t ctx, char *line)
   size_t outdatalen;
   char *keyidstr;
   card_t card;
-  int direct = 0;
+  const char *keygrip = NULL;
 
   if ((rc = open_card (ctrl)))
     return rc;
 
-  if (!ctrl->card_ctx)
-    return gpg_error (GPG_ERR_UNSUPPORTED_OPERATION);
-
  /* We have to use a copy of the key ID because the function may use
      the pin_cb which in turn uses the assuan line buffer and thus
      overwriting the original line with the keyid */
@@ -1029,25 +1058,18 @@ cmd_pkauth (assuan_context_t ctx, char *line)
   /* When it's a keygrip, we directly use CARD, with no change of
      ctrl->card_ctx. */
   if (strlen (keyidstr) == 40)
-    {
-      card = app_do_with_keygrip (ctrl, KEYGRIP_ACTION_LOOKUP, keyidstr, 0);
-      direct = 1;
-    }
-  else
-    card = ctrl->card_ctx;
+    keygrip = keyidstr;
 
+  card = card_get (ctrl, keygrip);
   if (card)
     {
-      if (direct)
-        card_ref (card);
       rc = app_auth (card, ctrl, keyidstr, pin_cb, ctx,
                      ctrl->in_data.value, ctrl->in_data.valuelen,
                      &outdata, &outdatalen);
-      if (direct)
-        card_unref (card);
+      card_put (card);
     }
   else
-    rc = gpg_error (GPG_ERR_NO_SECKEY);
+    rc = gpg_error (GPG_ERR_UNSUPPORTED_OPERATION);
 
   xfree (keyidstr);
   if (rc)
@@ -1078,7 +1100,7 @@ cmd_pkdecrypt (assuan_context_t ctx, char *line)
   char *keyidstr;
   unsigned int infoflags;
   card_t card;
-  int direct = 0;
+  const char *keygrip = NULL;
 
   if ((rc = open_card (ctrl)))
     return rc;
@@ -1090,22 +1112,15 @@ cmd_pkdecrypt (assuan_context_t ctx, char *line)
   /* When it's a keygrip, we directly use CARD, with no change of
      ctrl->card_ctx. */
   if (strlen (keyidstr) == 40)
-    {
-      card = app_do_with_keygrip (ctrl, KEYGRIP_ACTION_LOOKUP, keyidstr, 0);
-      direct = 1;
-    }
-  else
-    card = ctrl->card_ctx;
+    keygrip = keyidstr;
 
+  card = card_get (ctrl, keygrip);
   if (card)
     {
-      if (direct)
-        card_ref (card);
       rc = app_decipher (card, ctrl, keyidstr, pin_cb, ctx,
                          ctrl->in_data.value, ctrl->in_data.valuelen,
                          &outdata, &outdatalen, &infoflags);
-      if (direct)
-        card_unref (card);
+      card_put (card);
     }
   else
     rc = gpg_error (GPG_ERR_NO_SECKEY);
@@ -1154,7 +1169,7 @@ cmd_getattr (assuan_context_t ctx, char *line)
   int rc;
   const char *keyword;
   card_t card;
-  int direct = 0;
+  const char *keygrip = NULL;
 
   if ((rc = open_card (ctrl)))
     return rc;
@@ -1166,24 +1181,15 @@ cmd_getattr (assuan_context_t ctx, char *line)
     *line++ = 0;
 
   if (strlen (line) == 40)
-    {
-      card = app_do_with_keygrip (ctrl, KEYGRIP_ACTION_LOOKUP, line, 0);
-      direct = 1;
-    }
-  else
-    card = ctrl->card_ctx;
+    keygrip = line;
 
+  card = card_get (ctrl, keygrip);
   if (card)
     {
-      if (direct)
-        card_ref (card);
-
       /* FIXME: Applications should not return sensitive data if the card
          is locked.  */
       rc = app_getattr (card, ctrl, keyword);
-
-      if (direct)
-        card_unref (card);
+      card_put (card);
     }
   else
     rc = gpg_error (GPG_ERR_NO_SECKEY);
@@ -1219,6 +1225,7 @@ cmd_setattr (assuan_context_t ctx, char *orig_line)
   size_t nbytes;
   char *line, *linebuf;
   int opt_inquire;
+  card_t card;
 
   opt_inquire = has_option (orig_line, "--inquire");
   orig_line = skip_options (orig_line);
@@ -1232,6 +1239,13 @@ cmd_setattr (assuan_context_t ctx, char *orig_line)
   if (!line)
     return out_of_core ();
 
+  card = card_get (ctrl, NULL);
+  if (!card)
+    {
+      xfree (linebuf);
+      return gpg_error (GPG_ERR_CARD_NOT_PRESENT);
+    }
+
   keyword = line;
   for (keywordlen=0; *line && !spacep (line); line++, keywordlen++)
     ;
@@ -1248,7 +1262,7 @@ cmd_setattr (assuan_context_t ctx, char *orig_line)
       assuan_end_confidential (ctx);
       if (!err)
         {
-          err = app_setattr (ctrl->card_ctx, ctrl, keyword, pin_cb, ctx,
+          err = app_setattr (card, ctrl, keyword, pin_cb, ctx,
                              value, nbytes);
           wipememory (value, nbytes);
           xfree (value);
@@ -1258,10 +1272,11 @@ cmd_setattr (assuan_context_t ctx, char *orig_line)
   else
     {
       nbytes = percent_plus_unescape_inplace (line, 0);
-      err = app_setattr (ctrl->card_ctx, ctrl, keyword, pin_cb, ctx,
+      err = app_setattr (card, ctrl, keyword, pin_cb, ctx,
                          (const unsigned char*)line, nbytes);
     }
 
+  card_put (card);
   xfree (linebuf);
   return err;
 }
@@ -1286,6 +1301,7 @@ cmd_writecert (assuan_context_t ctx, char *line)
   char *certid;
   unsigned char *certdata;
   size_t certdatalen;
+  card_t card;
 
   line = skip_options (line);
 
@@ -1299,25 +1315,31 @@ cmd_writecert (assuan_context_t ctx, char *line)
   if ((rc = open_card (ctrl)))
     return rc;
 
-  if (!ctrl->card_ctx)
+  card = card_get (ctrl, NULL);
+  if (!card)
     return gpg_error (GPG_ERR_UNSUPPORTED_OPERATION);
 
   certid = xtrystrdup (certid);
   if (!certid)
-    return out_of_core ();
+    {
+      card_put (card);
+      return out_of_core ();
+    }
 
   /* Now get the actual keydata. */
   rc = assuan_inquire (ctx, "CERTDATA",
                        &certdata, &certdatalen, MAXLEN_CERTDATA);
   if (rc)
     {
+      card_put (card);
       xfree (certid);
       return rc;
     }
 
   /* Write the certificate to the card. */
-  rc = app_writecert (ctrl->card_ctx, ctrl, certid,
+  rc = app_writecert (card, ctrl, certid,
                       pin_cb, ctx, certdata, certdatalen);
+  card_put (card);
   xfree (certid);
   xfree (certdata);
 
@@ -1348,6 +1370,7 @@ cmd_writekey (assuan_context_t ctx, char *line)
   int force = has_option (line, "--force");
   unsigned char *keydata;
   size_t keydatalen;
+  card_t card;
 
   line = skip_options (line);
 
@@ -1361,12 +1384,16 @@ cmd_writekey (assuan_context_t ctx, char *line)
   if ((rc = open_card (ctrl)))
     return rc;
 
-  if (!ctrl->card_ctx)
+  card = card_get (ctrl, NULL);
+  if (!card)
     return gpg_error (GPG_ERR_UNSUPPORTED_OPERATION);
 
   keyid = xtrystrdup (keyid);
   if (!keyid)
-    return out_of_core ();
+    {
+      card_put (card);
+      return out_of_core ();
+    }
 
   /* Now get the actual keydata. */
   assuan_begin_confidential (ctx);
@@ -1379,8 +1406,9 @@ cmd_writekey (assuan_context_t ctx, char *line)
     }
 
   /* Write the key to the card. */
-  rc = app_writekey (ctrl->card_ctx, ctrl, keyid, force? 1:0,
+  rc = app_writekey (card, ctrl, keyid, force? 1:0,
                      pin_cb, ctx, keydata, keydatalen);
+  card_put (card);
   xfree (keyid);
   xfree (keydata);
 
@@ -1427,6 +1455,7 @@ cmd_genkey (assuan_context_t ctx, char *line)
   const char *s;
   char *opt_algo = NULL;
   time_t timestamp;
+  card_t card;
 
   force = has_option (line, "--force");
 
@@ -1459,7 +1488,8 @@ cmd_genkey (assuan_context_t ctx, char *line)
   if ((err = open_card (ctrl)))
     goto leave;
 
-  if (!ctrl->card_ctx)
+  card = card_get (ctrl, NULL);
+  if (!card)
     {
       err = gpg_error (GPG_ERR_UNSUPPORTED_OPERATION);
       goto leave;
@@ -1469,11 +1499,13 @@ cmd_genkey (assuan_context_t ctx, char *line)
   if (!keyref)
     {
       err = gpg_error_from_syserror ();
+      card_put (card);
       goto leave;
     }
-  err = app_genkey (ctrl->card_ctx, ctrl, keyref, opt_algo,
+  err = app_genkey (card, ctrl, keyref, opt_algo,
                     force? APP_GENKEY_FLAG_FORCE : 0,
                     timestamp, pin_cb, ctx);
+  card_put (card);
 
  leave:
   xfree (keyref_buffer);
@@ -1497,6 +1529,7 @@ cmd_random (assuan_context_t ctx, char *line)
   int rc;
   size_t nbytes;
   unsigned char *buffer;
+  card_t card;
 
   if (!*line)
     return set_error (GPG_ERR_ASS_PARAMETER,
@@ -1506,14 +1539,19 @@ cmd_random (assuan_context_t ctx, char *line)
   if ((rc = open_card (ctrl)))
     return rc;
 
-  if (!ctrl->card_ctx)
+  card = card_get (ctrl, NULL);
+  if (!card)
     return gpg_error (GPG_ERR_UNSUPPORTED_OPERATION);
 
   buffer = xtrymalloc (nbytes);
   if (!buffer)
-    return out_of_core ();
+    {
+      card_put (card);
+      return out_of_core ();
+    }
 
-  rc = app_get_challenge (ctrl->card_ctx, ctrl, nbytes, buffer);
+  rc = app_get_challenge (card, ctrl, nbytes, buffer);
+  card_put (card);
   if (!rc)
     {
       rc = assuan_send_data (ctx, buffer, nbytes);
@@ -1542,6 +1580,7 @@ cmd_passwd (assuan_context_t ctx, char *line)
   int rc;
   char *chvnostr;
   unsigned int flags = 0;
+  card_t card;
 
   if (has_option (line, "--reset"))
     flags |= APP_CHANGE_FLAG_RESET;
@@ -1567,13 +1606,18 @@ cmd_passwd (assuan_context_t ctx, char *line)
   if ((rc = open_card (ctrl)))
     return rc;
 
-  if (!ctrl->card_ctx)
+  card = card_get (ctrl, NULL);
+  if (!card)
     return gpg_error (GPG_ERR_UNSUPPORTED_OPERATION);
 
   chvnostr = xtrystrdup (chvnostr);
   if (!chvnostr)
-    return out_of_core ();
-  rc = app_change_pin (ctrl->card_ctx, ctrl, chvnostr, flags, pin_cb, ctx);
+    {
+      card_put (card);
+      return out_of_core ();
+    }
+  rc = app_change_pin (card, ctrl, chvnostr, flags, pin_cb, ctx);
+  card_put (card);
   if (rc)
     log_error ("command passwd failed: %s\n", gpg_strerror (rc));
   xfree (chvnostr);
@@ -1622,13 +1666,15 @@ static gpg_error_t
 cmd_checkpin (assuan_context_t ctx, char *line)
 {
   ctrl_t ctrl = assuan_get_pointer (ctx);
-  int rc;
+  gpg_error_t err;
   char *idstr;
+  card_t card;
 
-  if ((rc = open_card (ctrl)))
-    return rc;
+  if ((err = open_card (ctrl)))
+    return err;
 
-  if (!ctrl->card_ctx)
+  card = card_get (ctrl, NULL);
+  if (!card)
     return gpg_error (GPG_ERR_UNSUPPORTED_OPERATION);
 
   /* We have to use a copy of the key ID because the function may use
@@ -1636,14 +1682,18 @@ cmd_checkpin (assuan_context_t ctx, char *line)
      overwriting the original line with the keyid. */
   idstr = xtrystrdup (line);
   if (!idstr)
-    return out_of_core ();
+    {
+      card_put (card);
+      return out_of_core ();
+    }
 
-  rc = app_check_pin (ctrl->card_ctx, ctrl, idstr, pin_cb, ctx);
+  err = app_check_pin (card, ctrl, idstr, pin_cb, ctx);
+  card_put (card);
   xfree (idstr);
-  if (rc)
-    log_error ("app_check_pin failed: %s\n", gpg_strerror (rc));
+  if (err)
+    log_error ("app_check_pin failed: %s\n", gpg_strerror (err));
 
-  return rc;
+  return err;
 }
 
 
@@ -1863,10 +1913,15 @@ cmd_getinfo (assuan_context_t ctx, char *line)
   else if (!strcmp (line, "active_apps"))
     {
       ctrl_t ctrl = assuan_get_pointer (ctx);
-      if (!ctrl->card_ctx)
+      card_t card = card_get (ctrl, NULL);
+
+      if (!card)
         rc = 0; /* No current card - no active apps.  */
       else
-        rc = app_send_active_apps (ctrl->card_ctx, ctrl);
+        {
+          rc = app_send_active_apps (card, ctrl);
+          card_put (card);
+        }
     }
   else if (!strcmp (line, "all_active_apps"))
     {
@@ -1899,7 +1954,7 @@ static gpg_error_t
 cmd_restart (assuan_context_t ctx, char *line)
 {
   ctrl_t ctrl = assuan_get_pointer (ctx);
-  card_t card = ctrl->card_ctx;
+  card_t card = card_get (ctrl, NULL);
 
   (void)line;
 
@@ -1907,7 +1962,8 @@ cmd_restart (assuan_context_t ctx, char *line)
     {
       ctrl->card_ctx = NULL;
       ctrl->current_apptype = APPTYPE_NONE;
-      card_unref (card);
+      card_unref_locked (card);
+      card_put (card);
     }
   if (locked_session && ctrl->server_local == locked_session)
     {
@@ -1926,14 +1982,19 @@ static gpg_error_t
 cmd_disconnect (assuan_context_t ctx, char *line)
 {
   ctrl_t ctrl = assuan_get_pointer (ctx);
+  card_t card;
 
   (void)line;
 
-  if (!ctrl->card_ctx)
+  card = card_get (ctrl, NULL);
+  if (card)
+    {
+      apdu_disconnect (card->slot);
+      card_put (card);
+      return 0;
+    }
+  else
     return gpg_error (GPG_ERR_UNSUPPORTED_OPERATION);
-
-  apdu_disconnect (ctrl->card_ctx->slot);
-  return 0;
 }
 
 
@@ -1993,7 +2054,7 @@ cmd_apdu (assuan_context_t ctx, char *line)
   if ((rc = open_card (ctrl)))
     return rc;
 
-  card = ctrl->card_ctx;
+  card = card_get (ctrl, NULL);
   if (!card)
     return gpg_error (GPG_ERR_CARD_NOT_PRESENT);
 
@@ -2074,6 +2135,7 @@ cmd_apdu (assuan_context_t ctx, char *line)
   xfree (apdu);
 
  leave:
+  card_put (card);
   return rc;
 }
 
@@ -2208,6 +2270,7 @@ cmd_devinfo (assuan_context_t ctx, char *line)
   ctrl_t ctrl = assuan_get_pointer (ctx);
   gpg_error_t err = 0;
   int watch = 0;
+  card_t card;
 
   if (has_option (line, "--watch"))
     {
@@ -2237,10 +2300,15 @@ cmd_devinfo (assuan_context_t ctx, char *line)
 
   err = 0;
 
-  /* Remove reference(s) to the card.  */
-  ctrl->card_ctx = NULL;
-  ctrl->current_apptype = APPTYPE_NONE;
-  card_unref (ctrl->card_ctx);
+  card = card_get (ctrl, NULL);
+  if (card)
+    {
+      /* If any, remove reference to the card in CTRL.  */
+      ctrl->card_ctx = NULL;
+      ctrl->current_apptype = APPTYPE_NONE;
+      card_unref_locked (card);
+      card_put (card);
+    }
 
   /* Then, keep watching the status change.  */
   while (!err)