[mutter] backends: Allow opening /sys/ files on MetaLauncher

[Carlos Garnacho <carlosg src gnome org>]

commit 2d18b18fe5db4dfad695b0da0bd0fa515b8423ad
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Feb 11 00:00:59 2017 +0100

    backends: Allow opening /sys/ files on MetaLauncher
    
    libinput may want to access those for fetching LED status, as those are
    requested readonly, just forward the request to plain open().
    
    https://bugzilla.gnome.org/show_bug.cgi?id=778472

 src/backends/native/meta-launcher.c |   20 ++++++++++++++++++++
 1 files changed, 20 insertions(+), 0 deletions(-)
---
diff --git a/src/backends/native/meta-launcher.c b/src/backends/native/meta-launcher.c
index 75d07ce..b93a172 100644
--- a/src/backends/native/meta-launcher.c
+++ b/src/backends/native/meta-launcher.c
@@ -58,6 +58,7 @@ struct _MetaLauncher
   Login1Session *session_proxy;
   Login1Seat *seat_proxy;
 
+  GHashTable *sysfs_fds;
   gboolean session_active;
 
   int kms_fd;
@@ -220,6 +221,15 @@ on_evdev_device_open (const char  *path,
   int fd;
   int major, minor;
 
+  /* Allow readonly access to sysfs */
+  if (g_str_has_prefix (path, "/sys/"))
+    {
+      fd = open (path, flags);
+      if (fd >= 0)
+        g_hash_table_add (self->sysfs_fds, GINT_TO_POINTER (fd));
+      return fd;
+    }
+
   if (!get_device_info_from_path (path, &major, &minor))
     {
       g_set_error (error,
@@ -243,6 +253,14 @@ on_evdev_device_close (int      fd,
   int major, minor;
   GError *error = NULL;
 
+  if (g_hash_table_lookup (self->sysfs_fds, GINT_TO_POINTER (fd)))
+    {
+      /* /sys/ paths just need close() here */
+      g_hash_table_remove (self->sysfs_fds, GINT_TO_POINTER (fd));
+      close (fd);
+      return;
+    }
+
   if (!get_device_info_from_fd (fd, &major, &minor))
     {
       g_warning ("Could not get device info for fd %d: %m", fd);
@@ -540,6 +558,7 @@ meta_launcher_new (GError **error)
   self = g_slice_new0 (MetaLauncher);
   self->session_proxy = g_object_ref (session_proxy);
   self->seat_proxy = g_object_ref (seat_proxy);
+  self->sysfs_fds = g_hash_table_new (NULL, NULL);
 
   self->session_active = TRUE;
   self->kms_fd = kms_fd;
@@ -565,6 +584,7 @@ meta_launcher_free (MetaLauncher *self)
 {
   g_object_unref (self->seat_proxy);
   g_object_unref (self->session_proxy);
+  g_hash_table_destroy (self->sysfs_fds);
   g_free (self->kms_file_path);
   g_slice_free (MetaLauncher, self);
 }