card: Print the key's label if available.

* tools/gpg-card.h (struct key_info_s): Add field 'label'.
* tools/card-call-scd.c (learn_status_cb): Parse KEY-LABEL.
(scd_learn): Always request KEY-LABEL.
* tools/gpg-card.c (nullnone): New.
(list_one_kinfo, list_card): Use it.  Print the label.
--

PKCS#15 defines label which help to understand for what a key is
intended.  Print them.

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

tools/card-call-scd.c

@@ -157,6 +157,7 @@ release_card_info (card_info_t info)
   while (info->kinfo)
     {
       key_info_t kinfo = info->kinfo->next;
+      xfree (kinfo->label);
       xfree (info->kinfo);
       info->kinfo = kinfo;
     }
@@ -915,6 +916,36 @@ learn_status_cb (void *opaque, const char *line)
           xfree (parm->chvlabels);
           parm->chvlabels = xstrdup (line);
         }
+      else if (!memcmp (keyword, "KEY-LABEL", keywordlen))
+        {
+          /* The format of such a line is:
+           *   KEY-LABEL <keyref> [label|"-"]           */
+          const char *fields[2];
+          int nfields;
+          char *label;
+
+          line_buffer = pline = xstrdup (line);
+
+          if ((nfields = split_fields (line_buffer, fields, DIM (fields))) < 2)
+            goto leave;  /* not enough args - ignore.  */
+
+          keyref = fields[0];
+          /* We don't remove the percent escaping because that is only
+           * used in case of strange characters in the label; we
+           * should not print them.  Note that this info is only for
+           * human consumption, anyway.  */
+          label = xtrystrdup (fields[1]);
+          if (!label)
+            goto leave; /* We ignore malloc failures here.  */
+
+          /* Check whether we already have an item for the keyref.  */
+          kinfo = find_kinfo (parm, keyref);
+          if (!kinfo)  /* New entry.  */
+            kinfo = create_kinfo (parm, keyref);
+
+          xfree (kinfo->label);
+          kinfo->label = label;
+        }
       break;
 
     case 10:
@@ -1153,6 +1184,10 @@ scd_learn (card_info_t info)
       if (gpg_err_code (err) == GPG_ERR_INV_NAME
           || gpg_err_code (err) == GPG_ERR_UNSUPPORTED_OPERATION)
         err = 0; /* Not implemented or GETATTR not supported.  */
+      err = scd_getattr ("KEY-LABEL", info);
+      if (gpg_err_code (err) == GPG_ERR_INV_NAME
+          || gpg_err_code (err) == GPG_ERR_UNSUPPORTED_OPERATION)
+        err = 0; /* Not implemented or GETATTR not supported.  */
     }
 
   if (info == &dummyinfo)

tools/gpg-card.c

@@ -373,6 +373,14 @@ main (int argc, char **argv)
 }
 
 
+/* Return S or the string "[none]" if S is NULL.  */
+static GPGRT_INLINE const char *
+nullnone (const char *s)
+{
+  return s? s: "[none]";
+}
+
+
 /* Read data from file FNAME up to MAX_GET_DATA_FROM_FILE characters.
  * On error return an error code and stores NULL at R_BUFFER; on
  * success returns 0 and stores the number of bytes read at R_BUFLEN
@@ -668,7 +676,10 @@ list_one_kinfo (card_info_t info, key_info_t kinfo,
         {
           tty_fprintf (fp, "[none]\n");
           tty_fprintf (fp, "      keyref .....: %s\n", kinfo->keyref);
-          tty_fprintf (fp, "      algorithm ..: %s\n", kinfo->keyalgo);
+          if (kinfo->label)
+            tty_fprintf (fp, "      label ......: %s\n", kinfo->label);
+          tty_fprintf (fp, "      algorithm ..: %s\n",
+                       nullnone (kinfo->keyalgo));
           goto leave;
         }
 
@@ -690,10 +701,13 @@ list_one_kinfo (card_info_t info, key_info_t kinfo,
         }
       tty_fprintf (fp, "\n");
 
+      if (kinfo->label)
+        tty_fprintf (fp, "      label ......: %s\n", kinfo->label);
+
       if (!(err = scd_readkey (kinfo->keyref, &s_pkey)))
         {
           char *tmp = pubkey_algo_string (s_pkey, NULL);
-          tty_fprintf (fp, "      algorithm ..: %s\n", tmp);
+          tty_fprintf (fp, "      algorithm ..: %s\n", nullnone (tmp));
           xfree (tmp);
           gcry_sexp_release (s_pkey);
           s_pkey = NULL;
@@ -701,7 +715,8 @@ list_one_kinfo (card_info_t info, key_info_t kinfo,
       else
         {
           maybe_set_card_removed (info, err);
-          tty_fprintf (fp, "      algorithm ..: %s\n", kinfo->keyalgo);
+          tty_fprintf (fp, "      algorithm ..: %s\n",
+                       nullnone (kinfo->keyalgo));
         }
 
       if (kinfo->fprlen && kinfo->created)
@@ -785,7 +800,8 @@ list_one_kinfo (card_info_t info, key_info_t kinfo,
       if (label_keyref)
         tty_fprintf (fp, "      keyref .....: %s\n", label_keyref);
       if (kinfo)
-        tty_fprintf (fp, "      algorithm ..: %s\n", kinfo->keyalgo);
+        tty_fprintf (fp, "      algorithm ..: %s\n",
+                     nullnone (kinfo->keyalgo));
     }
 
  leave:
@@ -1039,14 +1055,12 @@ list_card (card_info_t info, int no_key_lookup)
 {
   estream_t fp = opt.interactive? NULL : es_stdout;
 
-  tty_fprintf (fp, "Reader ...........: %s\n",
-               info->reader? info->reader : "[none]");
+  tty_fprintf (fp, "Reader ...........: %s\n", nullnone (info->reader));
   if (info->cardtype)
     tty_fprintf (fp, "Card type ........: %s\n", info->cardtype);
   if (info->cardversion)
     print_a_version (fp, "Card firmware ....:", info->cardversion);
-  tty_fprintf (fp, "Serial number ....: %s\n",
-               info->serialno? info->serialno : "[none]");
+  tty_fprintf (fp, "Serial number ....: %s\n", nullnone (info->serialno));
   tty_fprintf (fp, "Application type .: %s%s%s%s\n",
                app_type_string (info->apptype),
                info->apptype == APP_TYPE_UNKNOWN && info->apptypestr? "(":"",

tools/gpg-card.h

@@ -125,6 +125,9 @@ struct key_info_s
   const char *keyalgo;
   enum gcry_pk_algos keyalgo_id;
 
+  /* An optional malloced label for the key.  */
+  char *label;
+
   /* The three next items are mostly useful for OpenPGP cards.  */
   unsigned char fprlen;  /* Use length of the next item.  */
   unsigned char fpr[32]; /* The binary fingerprint of length FPRLEN.  */