gpgsm: Extend --learn-card by an optional s/n argument.

* agent/command.c (cmd_learn): Allow for s/n argument.
* agent/learncard.c (agent_handle_learn): Ditto.
* agent/call-scd.c (agent_card_learn): Ditto.  Pass it on to scd.

* scd/command.c (cmd_switchcard): Factor most code out to ...
(switchcard_core): new.
(cmd_learn): Add option --demand to specify a s/n.

* sm/gpgsm.c (main): Allow a s/n argument for --learn-card.
--

This help Kleopatra to get a stable certificate listing.
GnuPG-bug-id: 7379

agent/agent.h

@@ -731,7 +731,7 @@ int agent_tpm2d_pkdecrypt (ctrl_t ctrl, const unsigned char *cipher,
 			   char **r_buf, size_t *r_len);
 
 /*-- call-scd.c --*/
-int agent_card_learn (ctrl_t ctrl,
+int agent_card_learn (ctrl_t ctrl, const char *demand_sn,
                       void (*kpinfo_cb)(void*, const char *),
                       void *kpinfo_cb_arg,
                       void (*certinfo_cb)(void*, const char *),
@@ -780,7 +780,8 @@ gpg_error_t agent_card_keyinfo (ctrl_t ctrl, const char *keygrip,
                                 int cap, struct card_key_info_s **result);
 
 /*-- learncard.c --*/
-int agent_handle_learn (ctrl_t ctrl, int send, void *assuan_context, int force);
+int agent_handle_learn (ctrl_t ctrl, int send, void *assuan_context,
+                        int force, const char *demand_sn);
 
 
 /*-- cvt-openpgp.c --*/

agent/call-scd.c

@@ -260,10 +260,14 @@ learn_status_cb (void *opaque, const char *line)
   return err;
 }
 
+
 /* Perform the LEARN command and return a list of all private keys
-   stored on the card. */
+ * stored on the card.  If DEMAND_SN is given the info is returned for
+ * the card with that S/N instead of the current card.  This may then
+ * switch the current card.  */
 int
 agent_card_learn (ctrl_t ctrl,
+                  const char *demand_sn,
                   void (*kpinfo_cb)(void*, const char *),
                   void *kpinfo_cb_arg,
                   void (*certinfo_cb)(void*, const char *),
@@ -273,6 +277,7 @@ agent_card_learn (ctrl_t ctrl,
 {
   int rc;
   struct learn_parm_s parm;
+  char line[ASSUAN_LINELENGTH];
 
   rc = start_scd (ctrl);
   if (rc)
@@ -285,7 +290,13 @@ agent_card_learn (ctrl_t ctrl,
   parm.certinfo_cb_arg = certinfo_cb_arg;
   parm.sinfo_cb = sinfo_cb;
   parm.sinfo_cb_arg = sinfo_cb_arg;
-  rc = assuan_transact (daemon_ctx (ctrl), "LEARN --force",
+
+  if (demand_sn && *demand_sn)
+    snprintf (line, sizeof line, "LEARN --demand=%s --force", demand_sn);
+  else
+    snprintf (line, sizeof line, "LEARN --force");
+
+  rc = assuan_transact (daemon_ctx (ctrl), line,
                         NULL, NULL, NULL, NULL,
                         learn_status_cb, &parm);
   if (rc)

agent/command.c

@@ -2376,27 +2376,31 @@ cmd_get_confirmation (assuan_context_t ctx, char *line)
 
 
 static const char hlp_learn[] =
-  "LEARN [--send] [--sendinfo] [--force]\n"
+  "LEARN [--send] [--sendinfo] [--force] [SERIALNO]\n"
   "\n"
   "Learn something about the currently inserted smartcard.  With\n"
   "--sendinfo information about the card is returned; with --send\n"
   "the available certificates are returned as D lines; with --force\n"
-  "private key storage will be updated by the result.";
+  "private key storage will be updated by the result. With SERIALNO\n"
+  "given the current card is first switched to the specified one.";
 static gpg_error_t
 cmd_learn (assuan_context_t ctx, char *line)
 {
   ctrl_t ctrl = assuan_get_pointer (ctx);
   gpg_error_t err;
   int send, sendinfo, force;
+  const char *demand_sn;
 
   send = has_option (line, "--send");
   sendinfo = send? 1 : has_option (line, "--sendinfo");
   force = has_option (line, "--force");
+  line = skip_options (line);
+  demand_sn = *line? line : NULL;
 
   if (ctrl->restricted)
     return leave_cmd (ctx, gpg_error (GPG_ERR_FORBIDDEN));
 
-  err = agent_handle_learn (ctrl, send, sendinfo? ctx : NULL, force);
+  err = agent_handle_learn (ctrl, send, sendinfo? ctx : NULL, force, demand_sn);
   return leave_cmd (ctx, err);
 }
 

agent/learncard.c

@@ -295,10 +295,14 @@ send_cert_back (ctrl_t ctrl, const char *id, void *assuan_context)
   return 0;
 }
 
+
 /* Perform the learn operation.  If ASSUAN_CONTEXT is not NULL and
-   SEND is true all new certificates are send back via Assuan.  */
+ * SEND is true all new certificates are send back via Assuan.  If
+ * DEMAND_SN is not NULL it has a string with the serial number of the
+ * card requested. */
 int
-agent_handle_learn (ctrl_t ctrl, int send, void *assuan_context, int force)
+agent_handle_learn (ctrl_t ctrl, int send, void *assuan_context, int force,
+                    const char *demand_sn)
 {
   int rc;
   struct kpinfo_cb_parm_s parm;
@@ -328,7 +332,7 @@ agent_handle_learn (ctrl_t ctrl, int send, void *assuan_context, int force)
   cparm.ctrl = ctrl;
 
   /* Now gather all the available info. */
-  rc = agent_card_learn (ctrl, kpinfo_cb, &parm, certinfo_cb, &cparm,
+  rc = agent_card_learn (ctrl, demand_sn, kpinfo_cb, &parm, certinfo_cb, &cparm,
                          sinfo_cb, &sparm);
   if (!rc && (parm.error || cparm.error || sparm.error))
     rc = parm.error? parm.error : cparm.error? cparm.error : sparm.error;

doc/gpgsm.texi

@@ -291,11 +291,12 @@ Import the certificates from the PEM or binary encoded files as well as
 from signed-only messages.  This command may also be used to import a
 secret key from a PKCS#12 file.
 
-@item --learn-card
+@item --learn-card [@var{serialno}]
 @opindex learn-card
-Read information about the private keys from the smartcard and import
-the certificates from there.  This command utilizes the @command{gpg-agent}
-and in turn the @command{scdaemon}.
+Read information about the private keys from the current smartcard and import
+the certificates from there.  This command utilizes @command{gpg-agent}
+and in turn @command{scdaemon}.  If @var{serialno} is provided the
+system first makes that card the current one.
 
 @item --change-passphrase @var{user_id}
 @opindex change-passphrase

scd/command.c

@@ -384,28 +384,14 @@ cmd_serialno (assuan_context_t ctx, char *line)
 
 
 
-static const char hlp_switchcard[] =
-  "SWITCHCARD [<serialno>]\n"
-  "\n"
-  "Make the card with SERIALNO the current card.\n"
-  "The command \"getinfo card_list\" can be used to list\n"
-  "the serial numbers of inserted and known cards.  Note\n"
-  "that the command \"SERIALNO\" can be used to refresh\n"
-  "the list of known cards.  A simple SERIALNO status\n"
-  "is printed on success.";
+/* Helper for cmd_swicthcard and cmd_learn.  */
 static gpg_error_t
-cmd_switchcard (assuan_context_t ctx, char *line)
+switchcard_core (ctrl_t ctrl, const char *line)
 {
-  ctrl_t ctrl = assuan_get_pointer (ctx);
   gpg_error_t err = 0;
   unsigned char *sn_bin = NULL;
   size_t sn_bin_len = 0;
 
-  if ((err = open_card (ctrl)))
-    return err;
-
-  line = skip_options (line);
-
   if (*line)
     {
       sn_bin = hex_to_buffer (line, &sn_bin_len);
@@ -425,6 +411,30 @@ cmd_switchcard (assuan_context_t ctx, char *line)
 }
 
 
+static const char hlp_switchcard[] =
+  "SWITCHCARD [<serialno>]\n"
+  "\n"
+  "Make the card with SERIALNO the current card.\n"
+  "The command \"getinfo card_list\" can be used to list\n"
+  "the serial numbers of inserted and known cards.  Note\n"
+  "that the command \"SERIALNO\" can be used to refresh\n"
+  "the list of known cards.  A simple SERIALNO status\n"
+  "is printed on success.";
+static gpg_error_t
+cmd_switchcard (assuan_context_t ctx, char *line)
+{
+  ctrl_t ctrl = assuan_get_pointer (ctx);
+  gpg_error_t err;
+
+  if ((err = open_card (ctrl)))
+    return err;
+
+  line = skip_options (line);
+
+  return switchcard_core (ctrl, line);
+}
+
+
 static const char hlp_switchapp[] =
   "SWITCHAPP [<appname>]\n"
   "\n"
@@ -458,7 +468,8 @@ cmd_switchapp (assuan_context_t ctx, char *line)
 
 
 static const char hlp_learn[] =
-  "LEARN [--force] [--keypairinfo] [--reread] [--multi]\n"
+  "LEARN [--force] [--keypairinfo] [--reread] [--multi] KEYGRIP\n"
+  "LEARN [--demand=<serialno>] [--force] [--keypairinfo] [--reread] [--multi]\n"
   "\n"
   "Learn all useful information of the currently inserted card.  When\n"
   "used without the force options, the command might do an INQUIRE\n"
@@ -529,6 +540,8 @@ static const char hlp_learn[] =
   "\n"
   "The URL to be used for locating the entire public key.\n"
   "  \n"
+  "If KEYGRIP is given the card holding a key with that keygrip is used.\n"
+  "If --demand is used the card with the specified S/N is used.\n"
   "Note, that this function may even be used on a locked card.";
 static gpg_error_t
 cmd_learn (assuan_context_t ctx, char *line)
@@ -539,17 +552,37 @@ cmd_learn (assuan_context_t ctx, char *line)
   int opt_multi = has_option (line, "--multi");
   int opt_reread = has_option (line, "--reread");
   int opt_force = has_option (line, "--force");
+  const char *opt_demand;
   unsigned int flags;
   card_t card;
   const char *keygrip = NULL;
 
-  if ((rc = open_card (ctrl)))
-    return rc;
+  opt_demand = has_option_name (line, "--demand");
+  if (opt_demand)
+    {
+      if (*opt_demand != '=')
+        return set_error (GPG_ERR_ASS_PARAMETER, "missing value for option");
+      line = (char *)++opt_demand;
+      while (*line && !spacep (line))
+        line++;
+      if (*line)
+        *line++ = 0;
+    }
 
   line = skip_options (line);
   if (strlen (line) == 40)
     keygrip = line;
 
+  if ((rc = open_card (ctrl)))
+    return rc;
+
+  if (opt_demand)
+    {
+      rc = switchcard_core (ctrl, opt_demand);
+      if (rc)
+        return rc;
+    }
+
   card = card_get (ctrl, keygrip);
   if (!card)
     return gpg_error (GPG_ERR_CARD_NOT_PRESENT);

sm/call-agent.c

@@ -1275,14 +1275,17 @@ learn_cb (void *opaque, const void *buffer, size_t length)
   return 0;
 }
 
-/* Call the agent to learn about a smartcard */
+
+/* Call the agent to learn about a smartcard.  If SERIALNO is not NULL
+ * switch to the card with that s/n first.  */
 int
-gpgsm_agent_learn (ctrl_t ctrl)
+gpgsm_agent_learn (ctrl_t ctrl, const char *serialno)
 {
   int rc;
   struct learn_parm_s learn_parm;
   membuf_t data;
   size_t len;
+  char line[ASSUAN_LINELENGTH];
 
   rc = start_agent (ctrl);
   if (rc)
@@ -1297,7 +1300,10 @@ gpgsm_agent_learn (ctrl_t ctrl)
   learn_parm.ctrl = ctrl;
   learn_parm.ctx = agent_ctx;
   learn_parm.data = &data;
-  rc = assuan_transact (agent_ctx, "LEARN --send",
+  snprintf (line, sizeof line, "LEARN --send%s%s",
+            serialno? " -- ":"",
+            serialno? serialno:"");
+  rc = assuan_transact (agent_ctx, line,
                         learn_cb, &learn_parm,
                         NULL, NULL,
                         learn_status_cb, &learn_parm);

sm/gpgsm.c

@@ -2269,11 +2269,11 @@ main ( int argc, char **argv)
 
 
     case aLearnCard:
-      if (argc)
+      if (argc > 1)
         wrong_args ("--learn-card");
       else
         {
-          int rc = gpgsm_agent_learn (&ctrl);
+          int rc = gpgsm_agent_learn (&ctrl, argc? *argv : NULL);
           if (rc)
             log_error ("error learning card: %s\n", gpg_strerror (rc));
         }

sm/gpgsm.h

@@ -539,7 +539,7 @@ int gpgsm_agent_istrusted (ctrl_t ctrl, ksba_cert_t cert, const char *hexfpr,
                            struct rootca_flags_s *rootca_flags);
 int gpgsm_agent_havekey (ctrl_t ctrl, const char *hexkeygrip);
 int gpgsm_agent_marktrusted (ctrl_t ctrl, ksba_cert_t cert);
-int gpgsm_agent_learn (ctrl_t ctrl);
+int gpgsm_agent_learn (ctrl_t ctrl, const char *serialno);
 int gpgsm_agent_passwd (ctrl_t ctrl, const char *hexkeygrip, const char *desc);
 gpg_error_t gpgsm_agent_get_confirmation (ctrl_t ctrl, const char *desc);
 gpg_error_t gpgsm_agent_send_nop (ctrl_t ctrl);