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  1. JDK
  2. JDK-7132461

os::available throws IOException for Linux /proc files

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    • x86
    • linux

      FULL PRODUCT VERSION :
      java version "1.7.0_147-icedtea"
      OpenJDK Runtime Environment (IcedTea7 2.0) (Gentoo build 1.7.0_147-icedtea-b147)
      OpenJDK 64-Bit Server VM (build 21.0-b17, mixed mode)

      Same for:

      java version "1.6.0_29"
      Java(TM) SE Runtime Environment (build 1.6.0_29-b11)
      Java HotSpot(TM) 64-Bit Server VM (build 20.4-b02, mixed mode)

      ADDITIONAL OS VERSION INFORMATION :
      Linux tsdh 3.2.1-gentoo #1 SMP PREEMPT Sun Jan 22 21:06:25 CET 2012 x86_64 Intel(R) Core(TM)2 Duo CPU T8100 @ 2.10GHz GenuineIntel GNU/Linux

      A DESCRIPTION OF THE PROBLEM :
      Calling FileInputStream.available() always throws an IOException "Invalid argument" for FileInputStream of files in the Linux /proc file system.

      For example, this works just fine:

        FileInputStream fis = new FileInputStream("/etc/hosts");
        System.out.println(fis.available());

      But this throws an IOException:

        FileInputStream fis = new FileInputStream("/proc/cpuinfo");
        System.out.println(fis.available());

      Exception in thread "main" java.io.IOException: Invalid argument
      at java.io.FileInputStream.available(Native Method)
      at Foo.main(Foo.java:12)



      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      On a Linux system, execute

        FileInputStream fis = new FileInputStream("/proc/cpuinfo");
        System.out.println(fis.available());

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      Get some non-negative integer back from FileInputStream.available().
      ACTUAL -
      A java.io.IOException is thrown.

      ERROR MESSAGES/STACK TRACES THAT OCCUR :
      Exception in thread "main" java.io.IOException: Invalid argument
      at java.io.FileInputStream.available(Native Method)

      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      import java.io.FileInputStream;
      import java.io.IOException;

      public class Foo {
      public static void main(String[] args) throws IOException {
      FileInputStream fis = new FileInputStream("/etc/hosts");
      System.out.println(fis.available()); // Works fine

      fis = new FileInputStream("/proc/cpuinfo");
      System.out.println(fis.available()); // Throws IOException

      }
      }

      ---------- END SOURCE ----------

            dxu Dan Xu (Inactive)
            webbuggrp Webbug Group
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              Created:
              Updated:
              Resolved:
              Imported:
              Indexed: