tools: add tool for GPG test key generation

This tool can be utilized in unit tests whenever a valid GPG key without a passphrase is being required.

See ElektraInitiative#1981 for full discussion.

src/tools/elektra-gpg-testkey/CMakeLists.txt

@@ -0,0 +1,9 @@
+find_package (LibGpgme QUIET)
+if (NOT LIBGPGME_FOUND)
+    remove_tool (elektra-gpg-testkey "libgpgme not found")
+else ()
+    include_directories (${LIBGPGME_INCLUDE_DIRS})
+    add_executable (elektra-gpg-testkey elektra-gpg-testkey.c)
+    target_link_libraries (elektra-gpg-testkey ${LIBGPGME_LIBRARIES})
+    install (TARGETS elektra-gpg-testkey DESTINATION bin)
+endif ()

src/tools/elektra-gpg-testkey/elektra-gpg-testkey.c

@@ -0,0 +1,72 @@
+/**
+ * @file
+ *
+ * @brief tool for creating and finding the GPG test key to be used in Elektra's unit tests.
+ *
+ * @copyright BSD License (see LICENSE.md or https://www.libelektra.org)
+ *
+ */
+
+#include <gpgme.h>
+#include <stdio.h>
+
+int main()
+{
+    gpgme_error_t err;
+    gpgme_ctx_t ctx;
+    gpgme_key_t key;
+    gpgme_genkey_result_t res;
+
+	gpgme_check_version (NULL);
+	err = gpgme_engine_check_version (GPGME_PROTOCOL_OpenPGP);
+	if (err)
+	{
+        fprintf (stderr, "gpgme version check failed: %s\n",gpgme_strerror (err));
+		return -1;
+	}
+
+	// setup gpgme context
+	err = gpgme_new (&ctx);
+	if (err)
+	{
+		fprintf (stderr, "gpgme error: %s\n", gpgme_strerror (err));
+		return -1;
+	}
+
+    // look for the elektra key
+    err = gpgme_op_keylist_start(ctx,"elektra",1 /* secret keys only! */);
+    if(err)
+    {
+        fprintf (stderr, "gpgme error: %s\n", gpgme_strerror (err));
+        goto cleanup;
+    }
+
+    err = gpgme_op_keylist_next(ctx,&key);
+    if(err && gpg_err_code(err) != GPG_ERR_EOF)
+    {
+        fprintf (stderr, "gpgme error: %s\n", gpgme_strerror (err));
+        goto cleanup;
+    }
+
+    if(err && gpg_err_code(err) == GPG_ERR_EOF)
+    {
+        // create the elektra demo key
+        err = gpgme_op_createkey(ctx, "elektra testkey", "default", 0, 0, NULL, GPGME_CREATE_SIGN | GPGME_CREATE_ENCR | GPGME_CREATE_NOEXPIRE | GPGME_CREATE_NOPASSWD );
+        res = gpgme_op_genkey_result(ctx);
+        fprintf(stdout, "%s", res->fpr);
+    }
+    else
+    {
+        // display the key ID
+        fprintf(stdout, "%s", key->subkeys->fpr);
+        gpgme_key_release(key);
+        gpgme_op_keylist_end(ctx);
+    }
+
+	gpgme_release(ctx);
+	return 0;
+
+cleanup:
+    gpgme_release(ctx);
+    return -1;
+}