core: New export mode to export secret subkeys.

* src/gpgme.h.in (GPGME_EXPORT_MODE_SECRET_SUBKEY): New.
* src/export.c (check_mode): Allow new mode and check for invalid
combinations.
(export_keys_start): Return error if new mode flag is set.
* src/engine-gpg.c (export_common): Implement.
* src/gpgme-tool.c (cmd_export): New option --secret-subkey.
* tests/run-export.c (main): New option --secret-subkey.
--

This adds support for exporting secret subkeys (via gpg's
--export-secret-subkeys) to gpgme_op_export[_ext][_start].
The flag is not supported by gpgme_op_export_keys[_start] because
there is no way to specify which subkey(s) to export with these
functions.

GnuPG-bug-id: 5757

1 files changed, 5 insertions, 2 deletions

diff --git a/src/engine-gpg.c b/src/engine-gpg.c
index fd39ad76..f619a646 100644
--- a/src/engine-gpg.c
+++ b/src/engine-gpg.c
@@ -2354,7 +2354,8 @@ export_common (engine_gpg_t gpg, gpgme_export_mode_t mode,
   if ((mode & ~(GPGME_EXPORT_MODE_EXTERN
                 |GPGME_EXPORT_MODE_MINIMAL
                 |GPGME_EXPORT_MODE_SSH
-                |GPGME_EXPORT_MODE_SECRET)))
+                |GPGME_EXPORT_MODE_SECRET
+                |GPGME_EXPORT_MODE_SECRET_SUBKEY)))
     return gpg_error (GPG_ERR_NOT_SUPPORTED);
 
   if ((mode & GPGME_EXPORT_MODE_MINIMAL))
@@ -2379,7 +2380,9 @@ export_common (engine_gpg_t gpg, gpgme_export_mode_t mode,
     }
   else
     {
-      if ((mode & GPGME_EXPORT_MODE_SECRET))
+      if ((mode & GPGME_EXPORT_MODE_SECRET_SUBKEY))
+        err = add_arg (gpg, "--export-secret-subkeys");
+      else if ((mode & GPGME_EXPORT_MODE_SECRET))
         err = add_arg (gpg, "--export-secret-keys");
       else
         err = add_arg (gpg, "--export");