在aosp定制时，需要集成并调整CMFileManager的默认参数，
直接更改/aosp/packages/apps/CMFileManager/src/com/cyanogenmod/filemanager/preferences/FileManagerSettings.java中的SETTINGS_ACCESS_MODE("cm_filemanager_access_mode", AccessMode.SAFE)为 SETTINGS_ACCESS_MODE("cm_filemanager_access_mode", AccessMode.ROOT)，作用是想使rom安装后文件管理器默认就用root模式初使化。
但是打包安装后发现在某个ROM里打开后，CM文件管理器没有进入root模式，并且选项中也没有调整root模式这一个选项。
查看代码在src/com/cyanogenmod/filemanager/activities/preferences/GeneralPreferenceFragment.java中有这么一段代码是对访问模式是否显示进行调控制的：
private void updateAccessModeStatus() {
// If device is not rooted, or is a restricted user, this setting cannot be changed
final Context context = getActivity();
boolean restrictedAccess = AndroidHelper.isSecondaryUser(context) &&
FileManagerApplication.isRestrictSecondaryUsersAccess(context);
this.mAccessMode.setEnabled(FileManagerApplication.isDeviceRooted() && !restrictedAccess);
if (!FileManagerApplication.isDeviceRooted()) {
PreferenceCategory category = (PreferenceCategory) findPreference(
"general_advanced_settings");
category.removePreference(mAccessMode);
}
}
其中FileManagerApplication.isDeviceRooted()返回的全局变量是由如下代码初使化的：
// Check if the device is rooted
sIsDeviceRooted = areShellCommandsPresent();
/**
* Method that check if all shell commands are present in the device
*
* @return boolean Check if the device has all of the shell commands
*/
private boolean areShellCommandsPresent() {
try {
String shellCommands = getString(R.string.shell_required_commands);
String[] commands = shellCommands.split(","); //$NON-NLS-1$
int cc = commands.length;
if (cc == 0) {
//???
Log.w(TAG, "No shell commands."); //$NON-NLS-1$
return false;
}
for (int i = 0; i < cc; i++) {
String c = commands[i].trim();
if (c.length() == 0) continue;
File cmd = new File(c);
if (!cmd.exists() || !cmd.isFile()) {
Log.w(TAG,
String.format(
"Command %s not found. Exists: %s; IsFile: %s.", //$NON-NLS-1$
c,
String.valueOf(cmd.exists()),
String.valueOf(cmd.isFile())));
return false;
}
}
// All commands are present
return true;
} catch (Exception e) {
Log.e(TAG,
"Failed to read shell commands.", e); //$NON-NLS-1$
}
return false;
}
由代码可见，它需要有R.string.shell_required_commands中包含的所有文件都存在才判断为root模式。res/values/overlay.xml中找到所有的shell指令：
/system/bin/cat,
/system/bin/chmod,
/system/bin/chown,
/system/bin/dd,
/system/bin/df,
/system/bin/gzip,
/system/bin/id,
/system/bin/kill,
/system/bin/ln,
/system/bin/ls,
/system/bin/mkdir,
/system/bin/mount,
/system/bin/mv,
/system/bin/ps,
/system/bin/rm,
/system/bin/sh,
/system/xbin/awk,
/system/xbin/bunzip2,
/system/xbin/busybox,
/system/xbin/bzip2,
/system/xbin/cp,
/system/xbin/cut,
/system/xbin/dirname,
/system/xbin/echo,
/system/xbin/find,
/system/xbin/grep,
/system/xbin/groups,
/system/xbin/gunzip,
/system/xbin/pwd,
/system/xbin/readlink,
/system/xbin/stat,
/system/xbin/su,
/system/xbin/tar,
/system/xbin/xargs,
/system/xbin/md5sum,
/system/xbin/sha1sum
但我的rom里并没有/system/xbin/awk和其它一些文件。
经过在多个rom里对比，发现这个不正常的rom里的busybox相关工具编译不完整，最后完整编译后解决。
