Add ctx flag for auto-key-locate

* src/context.h (gpgme_context): Add auto_key_locate.
* src/engine-gpg.c (engine_gpg): Add auto_key_locate.
(gpg_set_engine_flags, build_argv): Handle auto_key_locate.
(gpg_release): Free auto_key_locate.
* src/gpgme.c (gpgme_release): Free auto_key_locate.
(gpgme_get_ctx_flag, gpgme_set_ctx_flag): Handle auto-key-locate.
* doc/gpgme.texi: Document auto-key-locate flag.
* tests/run-keylist.c (show_usage, main): Add --from-wkd option.

--
This enables users of GPGME to control more fine grained what
auto-key-locate does.  Especially for WKD lookups / refreshes
can this be useful.

GnuPG-Bug-Id: T2917
Differential Revision: https://dev.gnupg.org/D463

NEWS

@@ -4,12 +4,16 @@ Noteworthy changes in version 1.11.2 (unreleased)
  * Even for old versions of gpg a missing MDC will now lead to a
    decryption failure.
 
+ * Added context flag "auto-key-locate" to control the
+   behavior of GPGME_KEYLIST_MODE_LOCATE.
+
  * Interface changes relative to the 1.11.1 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_decrypt_result_t           EXTENDED: New field legacy_cipher_nomdc.
  gpgme_set_ctx_flag               EXTENDED: New flag 'ignore-mdc-error'.
  GPGME_AUDITLOG_DEFAULT                     NEW.
  GPGME_AUDITLOG_DIAG                        NEW.
+ gpgme_set_ctx_flag          EXTENDED: New flag 'auto-key-locate'.
  cpp: DecryptionResult::sessionKey          NEW.
  cpp: DecryptionResult::symkeyAlgo          NEW.
  cpp: DecryptionResult::isLegacyCipherNoMDC New.

doc/gpgme.texi

@@ -3096,6 +3096,16 @@ result of the former try had the decryption result flag
 @code{legacy_cipher_nomdc} set.  For failsafe reasons this flag is
 reset after each operation.
 
+@item "auto-key-locate"
+The string given in @var{value} is passed to gpg.  This can be used
+to change the behavior of a @code{GPGME_KEYLIST_MODE_LOCATE} keylisting.
+Valid values are documented in the GnuPG manual and the gpg man page under
+the option @option{--auto-key-locate}.
+Requires at least GnuPG 2.1.18.
+
+Note: Keys retrieved through @code{auto-key-locate} are automatically
+imported in the keyring.
+
 @end table
 
 This function returns @code{0} on success.

src/context.h

@@ -155,6 +155,9 @@ struct gpgme_context
   /* The optional request origin.  */
   char *request_origin;
 
+  /* The optional auto key locate options.  */
+  char *auto_key_locate;
+
   /* The locale for the pinentry.  */
   char *lc_ctype;
   char *lc_messages;

src/engine-gpg.c

@@ -140,6 +140,7 @@ struct engine_gpg
   struct gpgme_io_cbs io_cbs;
   gpgme_pinentry_mode_t pinentry_mode;
   char request_origin[10];
+  char *auto_key_locate;
 
   struct {
     unsigned int no_symkey_cache : 1;
@@ -453,6 +454,7 @@ gpg_release (void *engine)
     free_argv (gpg->argv);
   if (gpg->cmd.keyword)
     free (gpg->cmd.keyword);
+  free (gpg->auto_key_locate);
 
   gpgme_data_release (gpg->override_session_key);
   gpgme_data_release (gpg->diagnostics);
@@ -659,6 +661,14 @@ gpg_set_engine_flags (void *engine, const gpgme_ctx_t ctx)
   else
     *gpg->request_origin = 0;
 
+  if (ctx->auto_key_locate && have_gpg_version (gpg, "2.1.18"))
+    {
+      if (gpg->auto_key_locate)
+        free (gpg->auto_key_locate);
+      gpg->auto_key_locate = _gpgme_strconcat ("--auto-key-locate=",
+                                               ctx->auto_key_locate, NULL);
+    }
+
   gpg->flags.no_symkey_cache = (ctx->no_symkey_cache
                                 && have_gpg_version (gpg, "2.2.7"));
   gpg->flags.offline = (ctx->offline && have_gpg_version (gpg, "2.1.23"));
@@ -958,6 +968,19 @@ build_argv (engine_gpg_t gpg, const char *pgmname)
       argc++;
     }
 
+  if (gpg->auto_key_locate)
+    {
+      argv[argc] = strdup (gpg->auto_key_locate);
+      if (!argv[argc])
+        {
+          int saved_err = gpg_error_from_syserror ();
+          free (fd_data_map);
+          free_argv (argv);
+          return saved_err;
+        }
+      argc++;
+    }
+
   if (gpg->flags.no_symkey_cache)
     {
       argv[argc] = strdup ("--no-symkey-cache");

src/gpgme.c

@@ -249,6 +249,7 @@ gpgme_release (gpgme_ctx_t ctx)
   free (ctx->lc_messages);
   free (ctx->override_session_key);
   free (ctx->request_origin);
+  free (ctx->auto_key_locate);
   _gpgme_engine_info_release (ctx->engine_info);
   ctx->engine_info = NULL;
   DESTROY_LOCK (ctx->lock);
@@ -546,6 +547,13 @@ gpgme_set_ctx_flag (gpgme_ctx_t ctx, const char *name, const char *value)
     {
       ctx->ignore_mdc_error = abool;
     }
+  else if (!strcmp (name, "auto-key-locate"))
+    {
+      free (ctx->auto_key_locate);
+      ctx->auto_key_locate = strdup (value);
+      if (!ctx->auto_key_locate)
+        err = gpg_error_from_syserror ();
+    }
   else
     err = gpg_error (GPG_ERR_UNKNOWN_NAME);
 
@@ -599,6 +607,10 @@ gpgme_get_ctx_flag (gpgme_ctx_t ctx, const char *name)
     {
       return ctx->ignore_mdc_error? "1":"";
     }
+  else if (!strcmp (name, "auto-key-locate"))
+    {
+      return ctx->auto_key_locate? ctx->auto_key_locate : "";
+    }
   else
     return NULL;
 }

tests/run-keylist.c

@@ -57,6 +57,7 @@ show_usage (int ex)
          "  --import         import all keys\n"
          "  --offline        use offline mode\n"
          "  --from-file      list all keys in the given file\n"
+         "  --from-wkd       list key from a web key directory\n"
          "  --require-gnupg  required at least the given GnuPG version\n"
          , stderr);
   exit (ex);
@@ -100,6 +101,7 @@ main (int argc, char **argv)
   int only_secret = 0;
   int offline = 0;
   int from_file = 0;
+  int from_wkd = 0;
   gpgme_data_t data = NULL;
 
 
@@ -194,6 +196,12 @@ main (int argc, char **argv)
           gpgme_set_global_flag ("require-gnupg", *argv);
           argc--; argv++;
         }
+      else if (!strcmp (*argv, "--from-wkd"))
+        {
+          argc--; argv++;
+          mode |= GPGME_KEYLIST_MODE_LOCATE;
+          from_wkd = 1;
+        }
       else if (!strncmp (*argv, "--", 2))
         show_usage (1);
     }
@@ -213,6 +221,13 @@ main (int argc, char **argv)
 
   gpgme_set_offline (ctx, offline);
 
+  if (from_wkd)
+    {
+      err = gpgme_set_ctx_flag (ctx, "auto-key-locate",
+                                "clear,nodefault,wkd");
+      fail_if_err (err);
+    }
+
   if (from_file)
     {
       err = gpgme_data_new_from_file (&data, *argv, 1);