Use init to write usb typec props.
The sysfs nodes are owned by root, so we must use init to write to
them.
Bug: 21615151
Change-Id: Ia8c838827ff45794aa359443117ac85764cf3772
diff --git a/services/usb/java/com/android/server/usb/UsbPortManager.java b/services/usb/java/com/android/server/usb/UsbPortManager.java
index 52abcfe..7f182a4 100644
--- a/services/usb/java/com/android/server/usb/UsbPortManager.java
+++ b/services/usb/java/com/android/server/usb/UsbPortManager.java
@@ -26,8 +26,13 @@
import android.hardware.usb.UsbPortStatus;
import android.os.Handler;
import android.os.Message;
+import android.os.SystemClock;
+import android.os.SystemProperties;
import android.os.UEventObserver;
import android.os.UserHandle;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.system.OsConstants;
import android.util.ArrayMap;
import android.util.Log;
import android.util.Slog;
@@ -89,6 +94,9 @@
private static final String PORT_DATA_ROLE_HOST = "host";
private static final String PORT_DATA_ROLE_DEVICE = "device";
+ private static final String USB_TYPEC_PROP_PREFIX = "sys.usb.typec.";
+ private static final String USB_TYPEC_STATE = "sys.usb.typec.state";
+
// All non-trivial role combinations.
private static final int COMBO_SOURCE_HOST =
UsbPort.combineRolesAsBit(UsbPort.POWER_ROLE_SOURCE, UsbPort.DATA_ROLE_HOST);
@@ -621,16 +629,25 @@
return 0;
}
+ private static boolean fileIsRootWritable(String path) {
+ try {
+ // If the file is user writable, then it is root writable.
+ return (Os.stat(path).st_mode & OsConstants.S_IWUSR) != 0;
+ } catch (ErrnoException e) {
+ return false;
+ }
+ }
+
private static boolean canChangeMode(File portDir) {
- return new File(portDir, SYSFS_PORT_MODE).canWrite();
+ return fileIsRootWritable(new File(portDir, SYSFS_PORT_MODE).getPath());
}
private static boolean canChangePowerRole(File portDir) {
- return new File(portDir, SYSFS_PORT_POWER_ROLE).canWrite();
+ return fileIsRootWritable(new File(portDir, SYSFS_PORT_POWER_ROLE).getPath());
}
private static boolean canChangeDataRole(File portDir) {
- return new File(portDir, SYSFS_PORT_DATA_ROLE).canWrite();
+ return fileIsRootWritable(new File(portDir, SYSFS_PORT_DATA_ROLE).getPath());
}
private static String readFile(File dir, String filename) {
@@ -642,16 +659,29 @@
}
}
- private static boolean writeFile(File dir, String filename, String contents) {
- final File file = new File(dir, filename);
- try {
- try (FileWriter writer = new FileWriter(file)) {
- writer.write(contents);
- }
- return true;
- } catch (IOException ex) {
- return false;
+ private static boolean waitForState(String property, String state) {
+ // wait for the transition to complete.
+ // give up after 5 seconds.
+ // 5 seconds is probably too long, but we have seen hardware that takes
+ // over 3 seconds to change states.
+ String value = null;
+ for (int i = 0; i < 100; i++) {
+ // State transition is done when property is set to the new configuration
+ value = SystemProperties.get(property);
+ if (state.equals(value)) return true;
+ SystemClock.sleep(50);
}
+ Slog.e(TAG, "waitForState(" + state + ") for " + property + " FAILED: got " + value);
+ return false;
+ }
+
+ private static String propertyFromFilename(String filename) {
+ return USB_TYPEC_PROP_PREFIX + filename;
+ }
+
+ private static boolean writeFile(File dir, String filename, String contents) {
+ SystemProperties.set(propertyFromFilename(filename), contents);
+ return waitForState(USB_TYPEC_STATE, contents);
}
private static void logAndPrint(int priority, IndentingPrintWriter pw, String msg) {