rooted android read only file system error

Question

I'm trying to modify /etc/hosts/ file and for that I make a separate file in external storage and then cp it to the location. I'm getting these error messages:

01-14 18:51:51.069: E/HostsActivity(5356): rm failed for /etc/hosts, Read-only file system
01-14 18:51:51.079: E/HostsActivity(5356): failed on '/mnt/sdcard/hosts' - Cross-device link

What do I do?

I'm using RootTools.

My code:

        try {
            String fn = write_file("hosts", hostsData);
            RootTools.getShell(true).add(new Command(0, "rm /etc/hosts",  "mv " + fn + " /etc/hosts")
            {
                @Override
                public void output(int arg0, String arg1) {
                    // TODO Auto-generated method stub
                    Log.e("HostsActivity", arg1);
                }
            }).waitForFinish();
            tv_status.setText("Done");

        } catch (Exception ioe) {
            Log.e("HostsActivity", ioe.toString());
            tv_status.setText(ioe.toString());
        }

I have asked for root permissions in the beginning of the activity in the onCreate

if (!RootTools.isAccessGiven()) {
            TextView tv = new TextView(this);
            tv.setText("Root access not given. Please ensure root access.");
            setContentView(tv);
        }
    setContentView(R.layout.activity_hosts);

Answer 1

You need to remount /etc by default it is Read-only file system.
Than you need to check permissions on the /etc/hosts and maybe you need to correct file permissions using chmod command.