[glib/mcatanzaro/posix-spawn2] gsubprocess: ensure we test fd remapping on the posix_spawn codepath

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 1280daa576113571e7c54b37a625ca3b3fded877
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Thu Feb 25 12:21:38 2021 -0600

    gsubprocess: ensure we test fd remapping on the posix_spawn codepath
    
    We should run test_pass_fd twice, once using gspawn's fork/exec codepath
    and once attempting to use its posix_spawn codepath. There's no
    guarantee we'll actually get the posix_spawn codepath, but it works
    for now on Linux.
    
    This causes the test to fail if I break the fd remapping implementation
    in my previous commit. Without this, we fail to test fd remapping on the
    optimized codepath.

 gio/tests/gsubprocess.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)
---
diff --git a/gio/tests/gsubprocess.c b/gio/tests/gsubprocess.c
index 7e22678ec..202d9e796 100644
--- a/gio/tests/gsubprocess.c
+++ b/gio/tests/gsubprocess.c
@@ -1697,7 +1697,8 @@ test_child_setup (void)
 }
 
 static void
-test_pass_fd (void)
+do_test_pass_fd (GSubprocessFlags     flags,
+                 GSpawnChildSetupFunc child_setup)
 {
   GError *local_error = NULL;
   GError **error = &local_error;
@@ -1722,9 +1723,11 @@ test_pass_fd (void)
   needdup_fd_str = g_strdup_printf ("%d", needdup_pipefds[1] + 1);
 
   args = get_test_subprocess_args ("write-to-fds", basic_fd_str, needdup_fd_str, NULL);
-  launcher = g_subprocess_launcher_new (G_SUBPROCESS_FLAGS_NONE);
+  launcher = g_subprocess_launcher_new (flags);
   g_subprocess_launcher_take_fd (launcher, basic_pipefds[1], basic_pipefds[1]);
   g_subprocess_launcher_take_fd (launcher, needdup_pipefds[1], needdup_pipefds[1] + 1);
+  if (child_setup != NULL)
+    g_subprocess_launcher_set_child_setup (launcher, child_setup, NULL, NULL);
   proc = g_subprocess_launcher_spawnv (launcher, (const gchar * const *) args->pdata, error);
   g_ptr_array_free (args, TRUE);
   g_assert_no_error (local_error);
@@ -1754,6 +1757,29 @@ test_pass_fd (void)
   g_object_unref (proc);
 }
 
+static void
+empty_child_setup (gpointer user_data)
+{
+}
+
+static void
+test_pass_fd (void)
+{
+  /* Using a child setup function forces gspawn to use fork/exec
+   * rather than posix_spawn.
+   */
+  do_test_pass_fd (G_SUBPROCESS_FLAGS_NONE, empty_child_setup);
+
+  /* Try to test the optimized posix_spawn codepath instead of
+   * fork/exec. Currently this requires using INHERIT_FDS since gspawn's
+   * posix_spawn codepath does not currently handle closing
+   * non-inherited fds. Note that using INHERIT_FDS means our testing of
+   * g_subprocess_launcher_take_fd() is less-comprehensive than when
+   * using G_SUBPROCESS_FLAGS_NONE.
+   */
+  do_test_pass_fd (G_SUBPROCESS_FLAGS_INHERIT_FDS, NULL);
+}
+
 #endif
 
 static void