How write something to partition /system programmatically?

Question

I flashed my phone firmware LineageOS 13 Android 6.0.1 (Marshmallow). I hava also access root.

I created app for updater other an apps. This app put into /system/app. This app trying create file into /system, but it get error (Read-only file system).

here code

                try {
                    Runtime.getRuntime().exec("su && su mount -o rw,remount /system");

                    try(PrintWriter out = new PrintWriter(PATH + "/hash")) {
                        out.println(body);
                    }

                    Log.i(TAG, "create hash");
                }
                catch(Exception e1) {
                    e1.printStackTrace();
                    Log.e(TAG, e1.getMessage());
                }

here stack trace

W/System.err: java.io.FileNotFoundException: /system/hash: open failed: EROFS (Read-only file system)
W/System.err:     at libcore.io.IoBridge.open(IoBridge.java:452)
W/System.err:     at java.io.FileOutputStream.<init>(FileOutputStream.java:87)
W/System.err:     at java.io.FileOutputStream.<init>(FileOutputStream.java:127)
W/System.err:     at java.io.FileOutputStream.<init>(FileOutputStream.java:116)
W/System.err:     at java.io.PrintWriter.<init>(PrintWriter.java:168)
W/System.err:     at net.lockoil.updaterutmhelper.UpdaterService$Task$1.onResponse(UpdaterService.java:99)
W/System.err:     at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall$1$1.run(ExecutorCallAdapterFactory.java:68)
W/System.err:     at android.os.Handler.handleCallback(Handler.java:739)
W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
W/System.err:     at android.os.Looper.loop(Looper.java:148)
W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:5461)
W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
W/System.err: Caused by: android.system.ErrnoException: open failed: EROFS (Read-only file system)
W/System.err:     at libcore.io.Posix.open(Native Method)
W/System.err:     at libcore.io.BlockGuardOs.open(BlockGuardOs.java:186)
W/System.err:     at libcore.io.IoBridge.open(IoBridge.java:438)

How I can write something into /system programmatically?

check this out: [link](https://stackoverflow.com/a/11283906/6076979) — MojoJojo, Sep 11 '19 at 11:59

score 0 · Answer 1 · answered Sep 11 '19 at 12:00

0

You should first get root access by calling the su command and mount the /system as writable:

Runtime.getRuntime().exec("su && su mount -o rw,remount /system");

Then you should be able to write to your /system partition. Read more here: Writing file on system partition

answered Sep 11 '19 at 12:00

gi097

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No, not it helped – Lock Oil Sep 11 '19 at 12:40
Did you follow the steps from the link I provided? – gi097 Sep 13 '19 at 11:28

How write something to partition /system programmatically?

1 Answers1