trivial: move kernel version check into common library code

This will be used by more than one plugin in an upcoming commit.

libfwupdplugin/fu-common.c

@@ -21,6 +21,10 @@
 #include <cpuid.h>
 #endif
 
+#ifdef HAVE_UTSNAME_H
+#include <sys/utsname.h>
+#endif
+
 #ifdef HAVE_LIBARCHIVE
 #include <archive_entry.h>
 #include <archive.h>
@@ -34,6 +38,7 @@
 #include "fwupd-error.h"
 
 #include "fu-common-private.h"
+#include "fu-common-version.h"
 #include "fu-firmware.h"
 #include "fu-volume-private.h"
 
@@ -2569,6 +2574,54 @@ fu_common_kernel_locked_down (void)
 #endif
 }
 
+/**
+ * fu_common_check_kernel_version :
+ * @minimum_kernel: (not nullable): The minimum kernel version to check against
+ * @error: (nullable): optional return location for an error
+ *
+ * Determines if the system is running at least a certain required kernel version
+ *
+ * Since: 1.6.2
+ **/
+gboolean
+fu_common_check_kernel_version (const gchar *minimum_kernel, GError **error)
+{
+#ifdef HAVE_UTSNAME_H
+	struct utsname name_tmp;
+
+	g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+	g_return_val_if_fail (minimum_kernel == NULL, FALSE);
+
+	memset (&name_tmp, 0, sizeof(struct utsname));
+	if (uname (&name_tmp) < 0) {
+		g_set_error_literal (error,
+				     FWUPD_ERROR,
+				     FWUPD_ERROR_INTERNAL,
+				     "failed to read kernel version");
+		return FALSE;
+	}
+	if (fu_common_vercmp_full (name_tmp.release,
+				   minimum_kernel,
+				   FWUPD_VERSION_FORMAT_TRIPLET) < 0) {
+		g_set_error (error,
+			     FWUPD_ERROR,
+			     FWUPD_ERROR_INTERNAL,
+			     "kernel %s doesn't meet minimum %s",
+			     name_tmp.release, minimum_kernel);
+		return FALSE;
+	}
+
+	return TRUE;
+#else
+	g_set_error_literal (error,
+			     FWUPD_ERROR,
+			     FWUPD_ERROR_INTERNAL,
+			     "platform doesn't support checking for minimum Linux kernel");
+	return FALSE;
+#endif
+
+}
+
 /**
  * fu_common_cpuid:
  * @leaf: the CPUID level, now called the 'leaf' by Intel

libfwupdplugin/fu-common.h

@@ -371,6 +371,8 @@ gchar		*fu_common_strsafe		(const gchar	*str,
 gchar		*fu_common_strjoin_array	(const gchar	*separator,
 						 GPtrArray	*array);
 gboolean	 fu_common_kernel_locked_down	(void);
+gboolean	 fu_common_check_kernel_version	(const gchar	*minimum_kernel,
+						 GError		**error);
 gboolean	 fu_common_cpuid		(guint32	 leaf,
 						 guint32	*eax,
 						 guint32	*ebx,

libfwupdplugin/fwupdplugin.map

@@ -815,3 +815,9 @@ LIBFWUPDPLUGIN_1.6.1 {
     fu_version_string;
   local: *;
 } LIBFWUPDPLUGIN_1.6.0;
+
+LIBFWUPDPLUGIN_1.6.2 {
+  global:
+    fu_common_check_kernel_version;
+  local: *;
+} LIBFWUPDPLUGIN_1.6.1;

plugins/thunderbolt/fu-plugin-thunderbolt.c

@@ -7,7 +7,6 @@
 #include "config.h"
 
 #include <fwupdplugin.h>
-#include <sys/utsname.h>
 
 #include "fu-thunderbolt-device.h"
 #include "fu-thunderbolt-firmware.h"
@@ -17,33 +16,13 @@ static gboolean
 fu_plugin_thunderbolt_safe_kernel (FuPlugin *plugin, GError **error)
 {
 	g_autofree gchar *minimum_kernel = NULL;
-	struct utsname name_tmp;
-
-	memset (&name_tmp, 0, sizeof(struct utsname));
-	if (uname (&name_tmp) < 0) {
-		g_debug ("Failed to read current kernel version");
-		return TRUE;
-	}
 
 	minimum_kernel = fu_plugin_get_config_value (plugin, "MinimumKernelVersion");
 	if (minimum_kernel == NULL) {
 		g_debug ("Ignoring kernel safety checks");
 		return TRUE;
 	}
-
-	if (fu_common_vercmp_full (name_tmp.release,
-				   minimum_kernel,
-				   FWUPD_VERSION_FORMAT_TRIPLET) < 0) {
-		g_set_error (error,
-			     FWUPD_ERROR,
-			     FWUPD_ERROR_INTERNAL,
-			     "kernel %s may not have full Thunderbolt support",
-			     name_tmp.release);
-		return FALSE;
-	}
-	g_debug ("Using kernel %s (minimum %s)", name_tmp.release, minimum_kernel);
-
-	return TRUE;
+	return fu_common_check_kernel_version (minimum_kernel, error);
 }
 
 gboolean