scd: New options --info and --info-only for READKEY.

* scd/command.c (cmd_readkey): New options --info and --info-only.
* scd/app.c (app_readkey): New arg 'flags'.
* scd/app-common.h (APP_READKEY_FLAG_INFO): New.
(struct app_ctx_s): New args 'ctrl' and 'flags' for member readkey.
Change all implementers.
* scd/app-nks.c (do_readkey): Stub implementation of
APP_READKEY_FLAG_INFO.
* scd/app-openpgp.c (do_readkey): Implement APP_READKEY_FLAG_INFO.
* scd/app-piv.c (do_readkey): Ditto.
--

This feature allows to quickly get the keygrip and in most cases also
the usage flags for one specific keyref.  Example:

 <- readkey --info-only  PIV.9D
 -> S KEYPAIRINFO FC6061FB457224370B85C6F34DD56CD29E669620 PIV.9D e
 -> OK

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

1 files changed, 29 insertions, 16 deletions

diff --git a/scd/app-help.c b/scd/app-help.c
index f0f551c55..59221ea9c 100644
--- a/scd/app-help.c
+++ b/scd/app-help.c
@@ -52,26 +52,17 @@ app_help_count_bits (const unsigned char *a, size_t len)
 }
 
 
-/* Return the KEYGRIP for the certificate CERT as an hex encoded
-   string in the user provided buffer HEXKEYGRIP which must be of at
-   least 41 bytes. */
+/* Return the KEYGRIP for the canonical encoded public key (PK,PKLEN)
+ * as an hex encoded string in the user provided buffer HEXKEYGRIP
+ * which must be of at least 41 bytes. */
 gpg_error_t
-app_help_get_keygrip_string (ksba_cert_t cert, char *hexkeygrip)
+app_help_get_keygrip_string_pk (const void *pk, size_t pklen, char *hexkeygrip)
 {
   gpg_error_t err;
   gcry_sexp_t s_pkey;
-  ksba_sexp_t p;
-  size_t n;
-  unsigned char array[20];
+  unsigned char array[KEYGRIP_LEN];
 
-  p = ksba_cert_get_public_key (cert);
-  if (!p)
-    return gpg_error (GPG_ERR_BUG);
-  n = gcry_sexp_canon_len (p, 0, NULL, NULL);
-  if (!n)
-    return gpg_error (GPG_ERR_INV_SEXP);
-  err = gcry_sexp_sscan (&s_pkey, NULL, (char*)p, n);
-  xfree (p);
+  err = gcry_sexp_sscan (&s_pkey, NULL, pk, pklen);
   if (err)
     return err; /* Can't parse that S-expression. */
   if (!gcry_pk_get_keygrip (s_pkey, array))
@@ -81,12 +72,34 @@ app_help_get_keygrip_string (ksba_cert_t cert, char *hexkeygrip)
     }
   gcry_sexp_release (s_pkey);
 
-  bin2hex (array, 20, hexkeygrip);
+  bin2hex (array, KEYGRIP_LEN, hexkeygrip);
 
   return 0;
 }
 
 
+/* Return the KEYGRIP for the certificate CERT as an hex encoded
+   string in the user provided buffer HEXKEYGRIP which must be of at
+   least 41 bytes. */
+gpg_error_t
+app_help_get_keygrip_string (ksba_cert_t cert, char *hexkeygrip)
+{
+  gpg_error_t err;
+  ksba_sexp_t p;
+  size_t n;
+
+  p = ksba_cert_get_public_key (cert);
+  if (!p)
+    return gpg_error (GPG_ERR_BUG);
+  n = gcry_sexp_canon_len (p, 0, NULL, NULL);
+  if (!n)
+    return gpg_error (GPG_ERR_INV_SEXP);
+  err = app_help_get_keygrip_string_pk ((void*)p, n, hexkeygrip);
+  ksba_free (p);
+  return err;
+}
+
+
 gpg_error_t
 app_help_pubkey_from_cert (const void *cert, size_t certlen,
                            unsigned char **r_pk, size_t *r_pklen)