Issue with SuRandomAccessFile and SuFile

Hello John,

I tried few things with SuRandomAccessFile and I find an issue with SuFile.

Here is the code I tried which works fine with a File:

        try {
            SuRandomAccessFile file = SuRandomAccessFile.open(new File("/system/etc/hosts"), "r");
            String line;
            while ((line = file.readLine()) != null) {
                Log.e("TEST", line);
            }
        } catch (IOException e) {
            Log.e("TEST", "error", e);
        }

But if I use a SuFile instead of a java File:

        try {
            SuRandomAccessFile file = SuRandomAccessFile.open(new SuFile("/system/etc/hosts"), "r");
            String line;
            while ((line = file.readLine()) != null) {
                Log.e("TEST", line);
            }
        } catch (IOException e) {
            Log.e("TEST", "error", e);
        }

I always got an error:

2020-08-16 11:44:24.736 21996-21996/com.topjohnwu.libsuexample D/LIBSU: java.io.InterruptedIOException
        at com.topjohnwu.superuser.internal.ShellImpl$DefaultTask.run(ShellImpl.java:280)
        at com.topjohnwu.superuser.internal.ShellImpl.execTask(ShellImpl.java:233)
        at com.topjohnwu.superuser.internal.JobImpl.exec0(JobImpl.java:53)
        at com.topjohnwu.superuser.internal.JobImpl.exec(JobImpl.java:70)
        at com.topjohnwu.libsuexample.MainActivity$ExampleInitializer.onInit(MainActivity.java:84)
        at com.topjohnwu.superuser.internal.BuilderImpl.build(BuilderImpl.java:84)
        at com.topjohnwu.superuser.internal.BuilderImpl.build(BuilderImpl.java:58)
        at com.topjohnwu.superuser.internal.MGR.getShell(MGR.java:41)
        at com.topjohnwu.superuser.Shell.getShell(Shell.java:148)
        at com.topjohnwu.superuser.ShellUtils.fastCmdResult(ShellUtils.java:85)
        at com.topjohnwu.superuser.io.SuFile.cmdBool(SuFile.java:110)
        at com.topjohnwu.superuser.io.SuFile.exists(SuFile.java:184)
        at com.topjohnwu.superuser.internal.ShellIO.<init>(ShellIO.java:57)
        at com.topjohnwu.superuser.internal.ShellIO.get(ShellIO.java:75)
        at com.topjohnwu.superuser.internal.IOFactory.createShellIO(IOFactory.java:41)
        at com.topjohnwu.superuser.io.SuRandomAccessFile.open(SuRandomAccessFile.java:54)
        at com.topjohnwu.libsuexample.MainActivity.runIoTests(MainActivity.java:244)
        at com.topjohnwu.libsuexample.MainActivity.lambda$onCreate$5$MainActivity(MainActivity.java:219)
        at com.topjohnwu.libsuexample.-$$Lambda$MainActivity$a7zsI796bNp0TD7tk4yhXst0ak4.onClick(Unknown Source:2)
        at android.view.View.performClick(View.java:7259)
        at android.view.View.performClickInternal(View.java:7236)
        at android.view.View.access$3600(View.java:801)
        at android.view.View$PerformClick.run(View.java:27892)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
     Caused by: java.util.concurrent.ExecutionException: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference
        at java.util.concurrent.FutureTask.report(FutureTask.java:123)
        at java.util.concurrent.FutureTask.get(FutureTask.java:193)
        at com.topjohnwu.superuser.internal.ShellImpl$DefaultTask.run(ShellImpl.java:277)
        at com.topjohnwu.superuser.internal.ShellImpl.execTask(ShellImpl.java:233) 
        at com.topjohnwu.superuser.internal.JobImpl.exec0(JobImpl.java:53) 
        at com.topjohnwu.superuser.internal.JobImpl.exec(JobImpl.java:70) 
        at com.topjohnwu.libsuexample.MainActivity$ExampleInitializer.onInit(MainActivity.java:84) 
        at com.topjohnwu.superuser.internal.BuilderImpl.build(BuilderImpl.java:84) 
        at com.topjohnwu.superuser.internal.BuilderImpl.build(BuilderImpl.java:58) 
        at com.topjohnwu.superuser.internal.MGR.getShell(MGR.java:41) 
        at com.topjohnwu.superuser.Shell.getShell(Shell.java:148) 
        at com.topjohnwu.superuser.ShellUtils.fastCmdResult(ShellUtils.java:85) 
        at com.topjohnwu.superuser.io.SuFile.cmdBool(SuFile.java:110) 
        at com.topjohnwu.superuser.io.SuFile.exists(SuFile.java:184) 
        at com.topjohnwu.superuser.internal.ShellIO.<init>(ShellIO.java:57) 
        at com.topjohnwu.superuser.internal.ShellIO.get(ShellIO.java:75) 
        at com.topjohnwu.superuser.internal.IOFactory.createShellIO(IOFactory.java:41) 
        at com.topjohnwu.superuser.io.SuRandomAccessFile.open(SuRandomAccessFile.java:54) 
        at com.topjohnwu.libsuexample.MainActivity.runIoTests(MainActivity.java:244) 
        at com.topjohnwu.libsuexample.MainActivity.lambda$onCreate$5$MainActivity(MainActivity.java:219) 
        at com.topjohnwu.libsuexample.-$$Lambda$MainActivity$a7zsI796bNp0TD7tk4yhXst0ak4.onClick(Unknown Source:2) 
        at android.view.View.performClick(View.java:7259) 
        at android.view.View.performClickInternal(View.java:7236) 
        at android.view.View.access$3600(View.java:801) 
        at android.view.View$PerformClick.run(View.java:27892) 
        at android.os.Handler.handleCallback(Handler.java:883) 
        at android.os.Handler.dispatchMessage(Handler.java:100) 
        at android.os.Looper.loop(Looper.java:214) 
        at android.app.ActivityThread.main(ActivityThread.java:7356) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference
        at com.topjohnwu.superuser.internal.StreamGobbler.isEOS(StreamGobbler.java:46)
        at com.topjohnwu.superuser.internal.StreamGobbler$OUT.call(StreamGobbler.java:77)
        at com.topjohnwu.superuser.internal.StreamGobbler$OUT.call(StreamGobbler.java:66)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:919)

It comes from the StreamGobbler which tries to find the EOS when the BufferedReader reaches EOF first. I think it does not find the eos tag and isEOS fails.

Moreover, there is something strange with the isEOS implementation:

protected boolean isEOS(String line) {
        boolean eof = false;
        int sl = line.length() - 1;
        int tl = eos.length() - 1;
        if (sl >= tl) {
            eof = true;
            for (; tl >= 0; --tl, --sl) {
                if (eos.charAt(tl) != line.charAt(sl)) {
                    eof = false;
                    break;
                }
            }
            if (eof)
                line = sl >= 0 ? line.substring(0, sl + 1) : null;
        }
        if (list != null && line != null) {
            list.add(line);
            Utils.log(TAG, line);
        }
        return eof;
    }

line is never tested to be null at method start where it can becomes null and nullability is checked later.

Long story short: I might be using SuFile the wrong way. If not, there might be a bug with SuRandomAccessFile

Regards, Bruce

[PerfectSlayer]

I add a log into the com.topjohnwu.superuser.internal.StreamGobbler.OUT#call method to dump read lines and here is the result:

Device API:  
Device ABI: arm
  

I seem the com.topjohnwu.libsuexample.MainActivity.ExampleInitializer load a script and it fails to load/parse. You can see it runs some calls from the test_sync shell method. So the shell outputs error and seems to fail SuFile operations.

I also add a log into the com.topjohnwu.superuser.internal.StreamGobbler.ERR#call and I got a lot of errors:

sh: 
: not found
sh: shift
: not found
head: invalid number '1
'
sh: }
: not found
sh: 
: not found
sh: {
: not found
sh: {
: not found
sh: {
: not found
sh: {
: not found
sh: 
: not found
sh: 
: not found
sh: 
: not found
sh: 
: not found
sh: 
: not found
sh: }
: not found
sh: 
: not found
sh: api_level_arch_detect
: not found
sh: }
: not found
sh: 
: not found
sh: syntax error: unexpected word (expecting "do")

Is it working on your side?

EDIT: I just discover the whole example app is not working if I keep the bash.rc ExampleInitializer. I never had test / output from in the main screen when pressing test buttons. Removing it make the test feature work.

For the record, here is my configuration:

• Device: Pixel 2 / QQ3A.200705.002
• Magisk: 20.4 (patched boot from manager the fastboot flashed)
• Magisk Manager: 7.5.1

[PerfectSlayer]

Thanks for the fix, it should do the trick! 👍 There is another issue with you build script when building on Windows, I will make an issue to address it.