Allow user interaction with gpg2 process

This commit makes sure the parent process's stdin pipe can be used by the gpg2 signing process, allowing user interaction such as passing passphrases etc.

Author: TheAssassin

src/appimagetool.c

@@ -1215,7 +1215,14 @@ main (int argc, char *argv[])
                         fprintf(stderr, "\n");
                     }
 
-                    GSubprocess* sign_proc = g_subprocess_newv((const gchar* const*) sign_process_argv->pdata, G_SUBPROCESS_FLAGS_STDIN_PIPE, &error);
+                    // this should allow the user to, e.g., reply to a prompt
+                    GSubprocessFlags flags = G_SUBPROCESS_FLAGS_STDIN_INHERIT;
+
+                    if (sign_passphrase) {
+                        flags = G_SUBPROCESS_FLAGS_STDIN_PIPE;
+                    }
+
+                    GSubprocess* sign_proc = g_subprocess_newv((const gchar* const*) sign_process_argv->pdata, flags, &error);
 
                     if (sign_proc == NULL) {
                         fprintf(stderr, "ERROR: failed to create gpg process: %s\n", error->message);
@@ -1225,6 +1232,8 @@ main (int argc, char *argv[])
                     if (sign_passphrase) {
                         bool success = g_subprocess_communicate_utf8(sign_proc, sign_passphrase, NULL, NULL, NULL, &error);
 
+                        free(sign_passphrase_buffer);
+
                         if (!success) {
                             fprintf(stderr, "ERROR: failed to pass passphrase to gpg process: %s\n", error->message);
                             g_object_unref(sign_proc);