scd: Add --advanced option for READKEY.

* scd/command.c (cmd_readkey) : Support ADVANCED arg.
* scd/app.c (app_readcert): Add ADVANCED arg.
* scd/app-openpgp.c (do_readkey): Implement ADVANCED arg.
* scd/app-nks.c (do_readkey): Error return with GPG_ERR_NOT_SUPPORTED.

--
"SCD READKEY --advanced OPENPGP.3" returns key in advanced format.
With this suport, poldi-ctrl will be no longer needed.

Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>

scd/app-common.h

@@ -72,7 +72,7 @@ struct app_ctx_s {
     gpg_error_t (*learn_status) (app_t app, ctrl_t ctrl, unsigned int flags);
     gpg_error_t (*readcert) (app_t app, const char *certid,
                      unsigned char **cert, size_t *certlen);
-    gpg_error_t (*readkey) (app_t app, const char *certid,
+    gpg_error_t (*readkey) (app_t app, int advanced, const char *certid,
                     unsigned char **pk, size_t *pklen);
     gpg_error_t (*getattr) (app_t app, ctrl_t ctrl, const char *name);
     gpg_error_t (*setattr) (app_t app, const char *name,
@@ -154,7 +154,7 @@ gpg_error_t app_write_learn_status (app_t app, ctrl_t ctrl,
                                     unsigned int flags);
 gpg_error_t app_readcert (app_t app, const char *certid,
                   unsigned char **cert, size_t *certlen);
-gpg_error_t app_readkey (app_t app, const char *keyid,
+gpg_error_t app_readkey (app_t app, int advanced, const char *keyid,
                  unsigned char **pk, size_t *pklen);
 gpg_error_t app_getattr (app_t app, ctrl_t ctrl, const char *name);
 gpg_error_t app_setattr (app_t app, const char *name,

scd/app-nks.c

@@ -618,13 +618,17 @@ do_readcert (app_t app, const char *certid,
    certificate parsing code in commands.c:cmd_readkey.  For internal
    use PK and PKLEN may be NULL to just check for an existing key.  */
 static gpg_error_t
-do_readkey (app_t app, const char *keyid, unsigned char **pk, size_t *pklen)
+do_readkey (app_t app, int advanced, const char *keyid,
+            unsigned char **pk, size_t *pklen)
 {
   gpg_error_t err;
   unsigned char *buffer[2];
   size_t buflen[2];
   unsigned short path[1] = { 0x4500 };
 
+  if (advanced)
+    return GPG_ERR_NOT_SUPPORTED;
+
   /* We use a generic name to retrieve PK.AUT.IFD-SPK.  */
   if (!strcmp (keyid, "$IFDAUTHKEY") && app->app_local->nks_version >= 3)
     ;
@@ -698,7 +702,7 @@ do_writekey (app_t app, ctrl_t ctrl,
   else
     return gpg_error (GPG_ERR_INV_ID);
 
-  if (!force && !do_readkey (app, keyid, NULL, NULL))
+  if (!force && !do_readkey (app, 0, keyid, NULL, NULL))
     return gpg_error (GPG_ERR_EEXIST);
 
   /* Parse the S-expression.  */

scd/app-openpgp.c

@@ -1726,7 +1726,8 @@ do_learn_status (app_t app, ctrl_t ctrl, unsigned int flags)
    buffer. On error PK and PKLEN are not changed and an error code is
    returned.  */
 static gpg_error_t
-do_readkey (app_t app, const char *keyid, unsigned char **pk, size_t *pklen)
+do_readkey (app_t app, int advanced, const char *keyid,
+            unsigned char **pk, size_t *pklen)
 {
 #if GNUPG_MAJOR_VERSION > 1
   gpg_error_t err;
@@ -1749,7 +1750,30 @@ do_readkey (app_t app, const char *keyid, unsigned char **pk, size_t *pklen)
   buf = app->app_local->pk[keyno].key;
   if (!buf)
     return gpg_error (GPG_ERR_NO_PUBKEY);
-  *pklen = app->app_local->pk[keyno].keylen;;
+
+  if (advanced)
+    {
+      gcry_sexp_t s_key;
+
+      err = gcry_sexp_new (&s_key, buf, app->app_local->pk[keyno].keylen, 0);
+      if (err)
+        return err;
+
+      *pklen = gcry_sexp_sprint (s_key, GCRYSEXP_FMT_ADVANCED, NULL, 0);
+      *pk = xtrymalloc (*pklen);
+      if (!*pk)
+        {
+          err = gpg_error_from_syserror ();
+          *pklen = 0;
+          return err;
+        }
+
+      gcry_sexp_sprint (s_key, GCRYSEXP_FMT_ADVANCED, *pk, *pklen);
+      gcry_sexp_release (s_key);
+    }
+  else
+    {
+      *pklen = app->app_local->pk[keyno].keylen;
       *pk = xtrymalloc (*pklen);
       if (!*pk)
         {
@@ -1758,6 +1782,8 @@ do_readkey (app_t app, const char *keyid, unsigned char **pk, size_t *pklen)
           return err;
         }
       memcpy (*pk, buf, *pklen);
+    }
+
   return 0;
 #else
   return gpg_error (GPG_ERR_NOT_IMPLEMENTED);

scd/app.c

@@ -612,7 +612,8 @@ app_readcert (app_t app, const char *certid,
 
    This function might not be supported by all applications.  */
 gpg_error_t
-app_readkey (app_t app, const char *keyid, unsigned char **pk, size_t *pklen)
+app_readkey (app_t app, int advanced, const char *keyid,
+             unsigned char **pk, size_t *pklen)
 {
   gpg_error_t err;
 
@@ -630,7 +631,7 @@ app_readkey (app_t app, const char *keyid, unsigned char **pk, size_t *pklen)
   err = lock_reader (app->slot, NULL /*FIXME*/);
   if (err)
     return err;
-  err= app->fnc.readkey (app, keyid, pk, pklen);
+  err= app->fnc.readkey (app, advanced, keyid, pk, pklen);
   unlock_reader (app->slot);
   return err;
 }

scd/command.c

@@ -729,17 +729,19 @@ cmd_readcert (assuan_context_t ctx, char *line)
 
 
 static const char hlp_readkey[] =
-  "READKEY <keyid>\n"
+  "READKEY [--advanced] <keyid>\n"
   "\n"
   "Return the public key for the given cert or key ID as a standard\n"
   "S-expression.\n"
+  "In --advanced mode it returns the S-expression in advanced format.\n"
   "\n"
-  "Note, that this function may even be used on a locked card.";
+  "Note that this function may even be used on a locked card.";
 static gpg_error_t
 cmd_readkey (assuan_context_t ctx, char *line)
 {
   ctrl_t ctrl = assuan_get_pointer (ctx);
   int rc;
+  int advanced = 0;
   unsigned char *cert = NULL;
   size_t ncert, n;
   ksba_cert_t kc = NULL;
@@ -750,11 +752,16 @@ cmd_readkey (assuan_context_t ctx, char *line)
   if ((rc = open_card (ctrl, NULL)))
     return rc;
 
+  if (has_option (line, "--advanced"))
+    advanced = 1;
+
+  line = skip_options (line);
+
   line = xstrdup (line); /* Need a copy of the line. */
   /* If the application supports the READKEY function we use that.
      Otherwise we use the old way by extracting it from the
      certificate.  */
-  rc = app_readkey (ctrl->app_ctx, line, &pk, &pklen);
+  rc = app_readkey (ctrl->app_ctx, advanced, line, &pk, &pklen);
   if (!rc)
     { /* Yeah, got that key - send it back.  */
       rc = assuan_send_data (ctx, pk, pklen);