GUnixMount: port unmount to GSubprocess

The existing code is buggy and now that we have GSubprocess, we should just use
it instead, allowing for some substantial reduction in complexity.

https://bugzilla.gnome.org/show_bug.cgi?id=724916

gio/gunixmount.c

@@ -28,6 +28,8 @@
 #include <unistd.h>
 
 #include <glib.h>
+#include "gsubprocess.h"
+#include "gioenums.h"
 #include "gunixvolumemonitor.h"
 #include "gunixmount.h"
 #include "gunixmounts.h"
@@ -240,147 +242,55 @@ g_unix_mount_can_eject (GMount *mount)
   return unix_mount->can_eject;
 }
 
-
-typedef struct {
-  GUnixMount *unix_mount;
-  int error_fd;
-  GIOChannel *error_channel;
-  GSource *error_channel_source;
-  GString *error_string;
-  gchar **argv;
-} UnmountEjectOp;
-
 static void
-unmount_eject_op_free (UnmountEjectOp *data)
+eject_unmount_done (GObject      *source,
-{
+                    GAsyncResult *result,
-  if (data->error_channel_source)
+                    gpointer      user_data)
-    {
-      g_source_destroy (data->error_channel_source);
-      g_source_unref (data->error_channel_source);
-    }
-  g_io_channel_unref (data->error_channel);
-  g_string_free (data->error_string, TRUE);
-  g_strfreev (data->argv);
-  close (data->error_fd);
-  g_free (data);
-}
-
-static void 
-eject_unmount_cb (GPid pid, gint status, gpointer user_data)
 {
+  GSubprocess *subprocess = G_SUBPROCESS (source);
   GTask *task = user_data;
-  UnmountEjectOp *data = g_task_get_task_data (task);
+  GError *error = NULL;
+  gchar *stderr_str;
 
-  if (g_task_return_error_if_cancelled (task))
+  if (!g_subprocess_communicate_utf8_finish (subprocess, result, NULL, &stderr_str, &error))
-    return;
-
-  g_spawn_close_pid (pid);
-
-  if (WEXITSTATUS (status) != 0)
     {
-      g_task_return_new_error (task, G_IO_ERROR, G_IO_ERROR_FAILED,
+      g_task_return_error (task, error);
-                               "%s", data->error_string->str);
+      g_error_free (error);
+    }
+  else /* successful communication */
+    {
+      if (!g_subprocess_get_successful (subprocess))
+        /* ...but bad exit code */
+        g_task_return_new_error (task, G_IO_ERROR, G_IO_ERROR_FAILED, "%s", stderr_str);
+      else
+        /* ...and successful exit code */
+        g_task_return_boolean (task, TRUE);
+
+      g_free (stderr_str);
     }
-  else
-    g_task_return_boolean (task, TRUE);
 
   g_object_unref (task);
 }
 
-static gboolean
-eject_unmount_read_error (GIOChannel *channel,
-                          GIOCondition condition,
-                          gpointer user_data)
-{
-  GTask *task = user_data;
-  UnmountEjectOp *data = g_task_get_task_data (task);
-  char buf[BUFSIZ];
-  gsize bytes_read;
-  GError *error;
-  GIOStatus status;
-
-  if (g_task_return_error_if_cancelled (task))
-    return FALSE;
-
-  error = NULL;
-read:
-  status = g_io_channel_read_chars (channel, buf, sizeof (buf), &bytes_read, &error);
-  if (status == G_IO_STATUS_NORMAL)
-   {
-     g_string_append_len (data->error_string, buf, bytes_read);
-     if (bytes_read == sizeof (buf))
-        goto read;
-   }
-  else if (status == G_IO_STATUS_EOF)
-    g_string_append_len (data->error_string, buf, bytes_read);
-  else if (status == G_IO_STATUS_ERROR)
-    {
-      if (data->error_string->len > 0)
-        g_string_append (data->error_string, "\n");
-
-      g_string_append (data->error_string, error->message);
-      g_error_free (error);
-
-      if (data->error_channel_source)
-        {
-          g_source_unref (data->error_channel_source);
-          data->error_channel_source = NULL;
-        }
-      return FALSE;
-    }
-
-  return TRUE;
-}
-
 static gboolean
 eject_unmount_do_cb (gpointer user_data)
 {
   GTask *task = user_data;
-  UnmountEjectOp *data = g_task_get_task_data (task);
-  GPid child_pid;
-  GSource *child_watch;
   GError *error = NULL;
+  GSubprocess *subprocess;
+  const gchar **argv;
+
+  argv = g_task_get_task_data (task);
 
   if (g_task_return_error_if_cancelled (task))
     return G_SOURCE_REMOVE;
 
-  if (!g_spawn_async_with_pipes (NULL,         /* working dir */
+  subprocess = g_subprocess_newv (argv, G_SUBPROCESS_FLAGS_STDOUT_SILENCE | G_SUBPROCESS_FLAGS_STDERR_PIPE, &error);
-                                 data->argv,
+  g_assert_no_error (error);
-                                 NULL,         /* envp */
-                                 G_SPAWN_DO_NOT_REAP_CHILD|G_SPAWN_SEARCH_PATH,
-                                 NULL,         /* child_setup */
-                                 NULL,         /* user_data for child_setup */
-                                 &child_pid,
-                                 NULL,           /* standard_input */
-                                 NULL,           /* standard_output */
-                                 &(data->error_fd),
-                                 &error)) {
-    g_assert (error != NULL);
-    goto handle_error;
-  }
 
-  data->error_string = g_string_new ("");
+  g_subprocess_communicate_utf8_async (subprocess, NULL,
-
+                                       g_task_get_cancellable (task),
-  data->error_channel = g_io_channel_unix_new (data->error_fd);
+                                       eject_unmount_done, task);
-  g_io_channel_set_flags (data->error_channel, G_IO_FLAG_NONBLOCK, &error);
-  if (error != NULL)
-    goto handle_error;
-
-  data->error_channel_source = g_io_create_watch (data->error_channel, G_IO_IN);
-  g_task_attach_source (task, data->error_channel_source,
-                        (GSourceFunc) eject_unmount_read_error);
-
-  child_watch = g_child_watch_source_new (child_pid);
-  g_task_attach_source (task, data->error_channel_source,
-                        (GSourceFunc) eject_unmount_cb);
-  g_source_unref (child_watch);
-
-handle_error:
-  if (error != NULL)
-    {
-      g_task_return_error (task, error);
-      g_object_unref (task);
-    }
 
   return G_SOURCE_REMOVE;
 }
@@ -393,15 +303,11 @@ eject_unmount_do (GMount              *mount,
                   char               **argv)
 {
   GUnixMount *unix_mount = G_UNIX_MOUNT (mount);
-  UnmountEjectOp *data;
   GTask *task;
   GSource *timeout;
 
-  data = g_new0 (UnmountEjectOp, 1);
-  data->argv = g_strdupv (argv);
-
   task = g_task_new (mount, cancellable, callback, user_data);
-  g_task_set_task_data (task, data, (GDestroyNotify)unmount_eject_op_free);
+  g_task_set_task_data (task, g_strdupv (argv), (GDestroyNotify) g_strfreev);
 
   if (unix_mount->volume_monitor != NULL)
     g_signal_emit_by_name (unix_mount->volume_monitor, "mount-pre-unmount", mount);