How to set executable permissions on a file in Android to execute using “Runtime.getRuntime().exec(..)”

Question

I'm currently trying to natively call on an executable on the shell from my Android Project which is in my application home directory. I can see via the command line when using ADB that my file is not getting executable file permissions, however. I've tried the following:

File file = new File(myFileLocation);
if(file.exists()){
boolean executable = file.setExecutable(true);
}

'executable' remains false.

I've also tried the following:

Process processChmod = Runtime.getRuntime().exec("/system/bin/chmod u+x " + myExecutableLocation);
processChmod.waitFor();

When I try to issue a command on the process, I get the following IOException:

java.io.IOException: Permission denied java.io.IOException: Error running exec(). Command: [/storage/emulated/0/myApp/iperf, -c, iperf.eltel.net] Working Directory: null Environment: null

The command I'm trying to issue is:

Runtime.getRuntime().exec("/storage/emulated/0/myApp/iperf -c iperf.eltel.net")

Again, at this stage, I can see that the file permissions on the process I wish to use is simply r/w and not executable. Any help appreciated! By the way, I'm trying to use the 'iPerf' C library and there is a compiled armeabi module as well as the original sources/JNI code. There are no compilation issues and this looks like a file permissions issue more than anything.

Answer 1

Files located on SD card aren't executable. Move the file to internal storage (eg to /data/local or, if you get permission denied, to data/local/tmp).

That is how I did it :

String filePath = getFilesDir().getAbsolutePath() + File.separator + "myFileName";
File myFile = new File(filePath);
if (!myFile.canExecute()) {
    Log.d("File is not executable, trying to make it executable ...");
    if (myFile .setExecutable(true)) {
        Log.d("File is executable");
    } else {
        Log.d("Failed to make the File executable");
    }
} else {
    Log.d("File is executable");
}

Answer 2

我认为Android的chmod无法理解u+x语法，请尝试使用744这样的数字符号。