Android添加用户组及自定义App权限的方法

# ls -l /dev/ttyUSB0
crw-rw---- 1 root root 188, 0 /dev/ttyUSB0

crw-rw---- 1 root selfgroup 188, 0 /dev/ttyUSB0

system\core\include\private\android_filesystem_config.h
/* This is the master Users and Groups config for the platform.
 * DO NOT EVER RENUMBER
 */
#define AID_ROOT  0 /* traditional unix root user */
#define AID_SYSTEM 1000 /* system server */
#define AID_RADIO  1001 /* telephony subsystem, RIL */
#define AID_BLUETOOTH 1002 /* bluetooth subsystem */
#define AID_GRAPHICS 1003 /* graphics devices */
#define AID_INPUT  1004 /* input devices */
#define AID_AUDIO  1005 /* audio devices */
#define AID_CAMERA 1006 /* camera devices */

/** 第1步 */
#define AID_SELF_GROUP 8011
/** 第2步 */
static const struct android_id_info android_ids[] = {
 { "root",  AID_ROOT, },
 {省略 .......................},
 /** 自定义组名 */
 {{ "selfgroup", AID_SELF_GROUP, },},
}

<uses-permission android:name="android.permission.SELFGROUP" />

Android源码/frameworks/base/data/etc/platform.xml
<permission name="android.permission.SELFGROUP" >
	<group gid="selfgroup" />
</permission>

Android源码/frameworks/base/core/res/AndroidManifest.xml
<permission android:name="android.permission.SELFGROUP"
 android:permissionGroup="android.permission-group.SELFGROUP"
 android:protectionLevel="dangerous"
 android:label="@string/permlab_sys_selfgroup"
 android:description="@string/permdesc_sys_selfgroup" />

Android源码/frameworks/base/services/java/com/android/server/am/ActivityManagerService.java
public final class ActivityManagerService extends ActivityManagerNative {
	static final String TAG = "ActivityManager";
	private final void startProcessLocked(ProcessRecord app,
		String hostingType, String hostingNameStr) {
		int uid = app.uid;
		int[] gids = null;
		StringBuilder buf = mStringBuilder;
		buf.setLength(0);
		buf.append("Start proc ");
		buf.append(app.processName);
		buf.append(" for ");
		buf.append(hostingType);
		if (hostingNameStr != null) {
			buf.append(" ");
			buf.append(hostingNameStr);
		}
		buf.append(": pid=");
		buf.append(startResult.pid);
		buf.append(" uid=");
		buf.append(uid);
		buf.append(" gids={");
		if (gids != null) {
			for (int gi=0; gi<gids.length; gi++) {
				if (gi != 0) buf.append(", ");
				buf.append(gids[gi]);
			}
		}
		buf.append("}");
		Slog.i(TAG, buf.toString());
	}
}

I/ActivityManager( 977): Start proc com.tencent.mm for activity com.tencent.mm/.ui.LauncherUI: pid=11060 uid=10258 gids={50258, 3003, 1028, 1015, 1023, 3002, 3001}