EROFS error while creating file

Question

I'm using this code to create a file but I'm getting this error:

java.io.IOEx: open failed: EROFS (Read only file system)

The system is mounted as rw and the app has SU permissions.

File f = new File(Environment.getRootDirectory().getPath().toString(), "/etc/init.d/script");
if (!f.exists()) {
    try {
        mountSystemRW();
        f.createNewFile();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

Why are you trying to do this? [If you want your app to start at boot there are better ways](http://stackoverflow.com/q/6391902/243712). — poolie, Apr 26 '14 at 20:56
possible duplicate of [Read only file system on Android](http://stackoverflow.com/questions/6066030/read-only-file-system-on-android) — poolie, Apr 26 '14 at 20:57

poolie · Answer 1 · 2014-04-26T21:05:10.797

0

The Android root filesystem is always mounted readonly because it's meant to contain only the system image.

If you have rooted your device you can run

# mount -o rw,remount /

edited Apr 26 '14 at 21:05

answered Apr 26 '14 at 20:52

poolie

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I mount system by this, it is okay? "mount -o rw,remount /system" – Hasta'98 Apr 26 '14 at 20:53
Actually `/` is different to `/system`. But, again, why are you trying to do this? The root filesystem is created at startup so putting a service file there won't help much. – poolie Apr 26 '14 at 21:05
I wanna create scripts using an app, so I need to create a file into "/system/etc/init.d", but I can't as you can see – Hasta'98 Apr 26 '14 at 21:30

score 0 · Answer 2 · answered Apr 23 '16 at 02:04

Regardless if the filesystem in question mounted read-only as normal, or has been changed to read-write, an application process is still never able to write to a file for which it lacks access rights.

Application code such as your java excerpt cannot run as root, period. Only helper processes can.

EROFS error while creating file

2 Answers2