From a028743f5c88dd7c27c102c34535f25b42ea2c5f Mon Sep 17 00:00:00 2001

From: Kyle Walker <kwalker@redhat.com>

Date: Mon, 23 Apr 2018 13:07:37 -0400

Subject: [PATCH] Backport of:

 https://bugs.freedesktop.org/attachment.cgi?id=138819

Signed-off-by: Kyle Walker <kwalker@redhat.com>

---

 src/polkitbackend/polkitbackendjsauthority.c | 76 +++++++++++++++++++++++++++-

 1 file changed, 74 insertions(+), 2 deletions(-)

diff --git a/src/polkitbackend/polkitbackendjsauthority.c b/src/polkitbackend/polkitbackendjsauthority.c

index 39ed718..fd1dbfd 100644

--- a/src/polkitbackend/polkitbackendjsauthority.c

+++ b/src/polkitbackend/polkitbackendjsauthority.c

@@ -83,6 +83,13 @@ struct _PolkitBackendJsAuthorityPrivate

   GMutex rkt_timeout_pending_mutex;

   gboolean rkt_timeout_pending;

+  /* avoid zombies by reap child in a new thread */

+  GThread *child_reaper_thread;

+  GMutex crt_init_mutex;

+  GCond crt_init_cond;

+  GMainContext *crt_context;

+  GMainLoop *crt_loop;

+

   /* A list of JSObject instances */

   GList *scripts;

 };

@@ -124,6 +131,7 @@ enum

 /* ---------------------------------------------------------------------------------------------------- */

 static gpointer runaway_killer_thread_func (gpointer user_data);

+static gpointer child_reaper_thread_func (gpointer user_data);

 static GList *polkit_backend_js_authority_get_admin_auth_identities (PolkitBackendInteractiveAuthority *authority,

                                                                      PolkitSubject                     *caller,

@@ -461,6 +469,18 @@ polkit_backend_js_authority_constructed (GObject *object)

   PolkitBackendJsAuthority *authority = POLKIT_BACKEND_JS_AUTHORITY (object);

   gboolean entered_request = FALSE;

+  g_mutex_init (&authority->priv->crt_init_mutex);

+  g_cond_init (&authority->priv->crt_init_cond);

+

+  authority->priv->child_reaper_thread = g_thread_new ("reap-child-thread",

+                                                       child_reaper_thread_func,

+                                                       authority);

+  /* wait for child_reaper_thread to set up its GMainContext */

+  g_mutex_lock (&authority->priv->crt_init_mutex);

+  while (authority->priv->crt_context == NULL)

+    g_cond_wait (&authority->priv->crt_init_cond, &authority->priv->crt_init_mutex);

+  g_mutex_unlock (&authority->priv->crt_init_mutex);

+

   authority->priv->rt = JS_NewRuntime (8L * 1024L * 1024L);

   if (authority->priv->rt == NULL)

     goto fail;

@@ -585,6 +605,15 @@ polkit_backend_js_authority_finalize (GObject *object)

   g_free (authority->priv->dir_monitors);

   g_strfreev (authority->priv->rules_dirs);

+  g_mutex_clear (&authority->priv->crt_init_mutex);

+  g_cond_clear (&authority->priv->crt_init_cond);

+

+  /* shut down the child reaper thread */

+  g_assert (authority->priv->crt_loop != NULL);

+  g_main_loop_quit (authority->priv->crt_loop);

+  g_thread_join (authority->priv->child_reaper_thread);

+  g_assert (authority->priv->crt_loop == NULL);

+

   JS_BeginRequest (authority->priv->cx);

   JS_RemoveObjectRoot (authority->priv->cx, &authority->priv->js_polkit);

   JS_RemoveObjectRoot (authority->priv->cx, &authority->priv->js_global);

@@ -1360,6 +1389,7 @@ get_signal_name (gint signal_number)

 typedef struct

 {

+  PolkitBackendJsAuthority *authority;

   GMainLoop *loop;

   GAsyncResult *res;

 } SpawnData;

@@ -1379,7 +1409,7 @@ js_polkit_spawn (JSContext  *cx,

                  unsigned    js_argc,

                  jsval      *vp)

 {

-  /* PolkitBackendJsAuthority *authority = POLKIT_BACKEND_JS_AUTHORITY (JS_GetContextPrivate (cx)); */

+  PolkitBackendJsAuthority *authority = POLKIT_BACKEND_JS_AUTHORITY (JS_GetContextPrivate (cx));

   JSBool ret = JS_FALSE;

   JSObject *array_object;

   gchar *standard_output = NULL;

@@ -1424,6 +1454,8 @@ js_polkit_spawn (JSContext  *cx,

       JS_free (cx, s);

     }

+  data.authority = authority;

+

   context = g_main_context_new ();

   loop = g_main_loop_new (context, FALSE);

@@ -1540,6 +1572,8 @@ js_polkit_user_is_in_netgroup (JSContext  *cx,

 typedef struct

 {

+  PolkitBackendJsAuthority *authority;

+

   GSimpleAsyncResult *simple; /* borrowed reference */

   GMainContext *main_context; /* may be NULL */

@@ -1572,11 +1606,43 @@ utils_child_watch_from_release_cb (GPid     pid,

                                    gint     status,

                                    gpointer user_data)

 {

+  g_print("Child(pid: %d) has been reaped!\n", pid);

+}

+

+/* ---------------------------------------------------------------------------------------------------- */

+

+static gpointer

+child_reaper_thread_func (gpointer user_data)

+{

+  PolkitBackendJsAuthority *authority = POLKIT_BACKEND_JS_AUTHORITY (user_data);

+

+  g_mutex_lock (&authority->priv->crt_init_mutex);

+

+  authority->priv->crt_context = g_main_context_new ();

+  authority->priv->crt_loop = g_main_loop_new (authority->priv->crt_context, FALSE);

+  g_main_context_push_thread_default (authority->priv->crt_context);

+

+  /* Signal the main thread that we're done constructing */

+  g_cond_signal (&authority->priv->crt_init_cond);

+  g_mutex_unlock (&authority->priv->crt_init_mutex);

+

+  g_main_loop_run (authority->priv->crt_loop);

+

+  g_main_context_pop_thread_default (authority->priv->crt_context);

+

+  g_main_loop_unref (authority->priv->crt_loop);

+  authority->priv->crt_loop = NULL;

+  g_main_context_unref (authority->priv->crt_context);

+  authority->priv->crt_context = NULL;

+

+  return NULL;

 }

+/* ---------------------------------------------------------------------------------------------------- */

 static void

 utils_spawn_data_free (UtilsSpawnData *data)

 {

+  PolkitBackendJsAuthority *authority = data->authority;

   if (data->timeout_source != NULL)

     {

       g_source_destroy (data->timeout_source);

@@ -1604,12 +1670,17 @@ utils_spawn_data_free (UtilsSpawnData *data)

        * Avoid taking a references to ourselves. but note that we need

        * to pass the GSource so we can nuke it once handled.

        */

+

+      /* avoid zombies by reaping child in a new thread

+       * add source to reap thread context

+       */

+      GMainContext *reap_context = authority->priv->crt_context;

       source = g_child_watch_source_new (data->child_pid);

       g_source_set_callback (source,

                              (GSourceFunc) utils_child_watch_from_release_cb,

                              source,

                              (GDestroyNotify) g_source_destroy);

-      g_source_attach (source, data->main_context);

+      g_source_attach (source, reap_context);

       g_source_unref (source);

       data->child_pid = 0;

     }

@@ -1776,6 +1847,7 @@ utils_spawn (const gchar *const  *argv,

   GError *error;

   data = g_slice_new0 (UtilsSpawnData);

+  data->authority = ((SpawnData *)user_data)->authority;

   data->timeout_seconds = timeout_seconds;

   data->simple = g_simple_async_result_new (NULL,

                                             callback,

-- 

2.14.3