gpg: Move S2K encoding function to a shared file.

* g10/passphrase.c (encode_s2k_iterations): Move function to ...
* common/openpgp-s2k.c: new file.  Remove default intialization code.
* common/openpgpdefs.h (S2K_DECODE_COUNT): New to keep only one copy.
* g10/call-agent.c (agent_get_s2k_count): Change to return the count
and print an error.
* agent/protect.c: Include openpgpdefs.h
* g10/card-util.c (gen_kdf_data): Adjust for changes
* g10/gpgcompose.c: Include call-agent.h.
(sk_esk): Adjust for changes.
* g10/passphrase (passphrase_to_dek): Adjust for changes.
* g10/main.h (S2K_DECODE_COUNT): Remove macro.

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

1 files changed, 19 insertions, 7 deletions

diff --git a/g10/call-agent.c b/g10/call-agent.c
index c958b84b7..91af2be39 100644
--- a/g10/call-agent.c
+++ b/g10/call-agent.c
@@ -1461,19 +1461,19 @@ gpg_agent_get_confirmation (const char *desc)
 }
 
 
-/* Return the S2K iteration count as computed by gpg-agent.  */
-gpg_error_t
-agent_get_s2k_count (unsigned long *r_count)
+/* Return the S2K iteration count as computed by gpg-agent.  On error
+ * print a warning and return a default value. */
+unsigned long
+agent_get_s2k_count (void)
 {
   gpg_error_t err;
   membuf_t data;
   char *buf;
-
-  *r_count = 0;
+  unsigned long count = 0;
 
   err = start_agent (NULL, 0);
   if (err)
-    return err;
+    goto leave;
 
   init_membuf (&data, 32);
   err = assuan_transact (agent_ctx, "GETINFO s2k_count",
@@ -1489,10 +1489,22 @@ agent_get_s2k_count (unsigned long *r_count)
         err = gpg_error_from_syserror ();
       else
         {
-          *r_count = strtoul (buf, NULL, 10);
+          count = strtoul (buf, NULL, 10);
           xfree (buf);
         }
     }
+
+ leave:
+  if (err || count < 65536)
+    {
+      /* Don't print an error if an older agent is used.  */
+      if (err && gpg_err_code (err) != GPG_ERR_ASS_PARAMETER)
+        log_error (_("problem with the agent: %s\n"), gpg_strerror (err));
+
+      /* Default to 65536 which was used up to 2.0.13.  */
+      return 65536;
+    }
+
   return err;
 }