sysfs: method to perform host identification

Add a new method to do host identification, which will first check
if the host device can be identified via the normal device ident
method. This will fail in case of embedded thunderbolt controller,
which do not have a DROM and have no device and vendor information
and thus no corresponding sysfs attributes. In that case we fall
back to using the SMBIOS/DMI information for the system to ident
the host.

boltd/bolt-sysfs.c

@@ -33,6 +33,9 @@
 #include <string.h>
 #include <sys/stat.h>
 
+typedef struct udev_device udev_device;
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (udev_device, udev_device_unref);
+
 void
 bolt_ident_clear (BoltIdent *id)
 {
@@ -240,6 +243,73 @@ bolt_sysfs_device_ident (struct udev_device *udev,
   return TRUE;
 }
 
+gboolean
+bolt_sysfs_host_ident (struct udev_device *dev,
+                       BoltIdent          *id,
+                       GError            **error)
+{
+  g_autoptr(udev_device) dmi = NULL;
+  struct udev *udev;
+  const char *name;
+  const char *vendor;
+  const char *attr;
+  gboolean ok;
+
+  g_return_val_if_fail (dev != NULL, FALSE);
+  g_return_val_if_fail (id != NULL, FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  /* First check if the host controller has normal device ident,
+   * which should be present for all controller that have a DROM. */
+  ok = bolt_sysfs_device_ident (dev, id, NULL);
+  if (ok)
+    return TRUE;
+
+  /* On embedded thunderbolt controllers without DROM, we
+   * fall back to using the SMBIOS/DMI system information */
+
+  udev = udev_device_get_udev (dev);
+  dmi = udev_device_new_from_syspath (udev, BOLT_SYSFS_DMI_ID);
+
+  if (dmi == NULL)
+    {
+      int code = errno;
+      g_set_error (error, BOLT_ERROR, BOLT_ERROR_UDEV,
+                   "could not open dmi/id device: %s",
+                   g_strerror (code));
+      return FALSE;
+    }
+
+  attr = BOLT_SYSFS_DMI_SYS_VENDOR;
+  vendor = sysfs_get_sysattr_value (dmi, attr, error);
+
+  if (vendor == NULL)
+    return FALSE;
+
+  /* Almost all systems are using the product_name attribute
+   * for the human readable string, with exception of Lenovo,
+   * that instead uses the product_version, so we special
+   * case that. */
+  attr = BOLT_SYSFS_DMI_PRODUCT_NAME;
+
+  if (!g_ascii_strcasecmp (vendor, "lenovo"))
+    {
+      attr = BOLT_SYSFS_DMI_PRODUCT_VERSION;
+      vendor = "Lenovo";
+    }
+
+  name = sysfs_get_sysattr_value (dmi, attr, error);
+
+  if (name == NULL)
+    return FALSE;
+
+  id->udev = g_steal_pointer (&dmi);
+  id->name = name;
+  id->vendor = vendor;
+
+  return TRUE;
+}
+
 static int
 bolt_syfs_count_tb_devices (struct udev        *udev,
                             struct udev_device *parent,

boltd/bolt-sysfs.h

@@ -72,6 +72,10 @@ gboolean             bolt_sysfs_device_ident (struct udev_device *udev,
                                               BoltIdent          *id,
                                               GError            **error);
 
+gboolean             bolt_sysfs_host_ident (struct udev_device *udev,
+                                            BoltIdent          *id,
+                                            GError            **error);
+
 int                  bolt_sysfs_count_hosts (struct udev *udev,
                                              GError     **error);