able to write named attributes to a read only file (Solaris)

[Rajendra Gutupalli]

Hi Alan,

It is surprising that I am able to add named attributes to a file with 
read only permissions in Solaris where as it throws FSE:Permission 
denied in Linux for the read only file.
Please see the following series of events I did in Solaris machine.

1) created a file "testfile1" set permissions to 777 and added a named 
attribute attr.2
2) changed the file "testfile1" permissions to 400 and tried adding 
attribute attr.3. it went successfully and used 'runat' command tool to 
see what are the attributes in files namespace.
3) changed  file  permissions of a attribute attr.3 and  tried to 
replace the attribute  now I got  FSE: Permission denied exception.
4) Again I added one more attribute attr.4 . it is successfully added to 
the same file "testfile1" with .
5) finally checked file  permissions.

Here the file "testfile1" lies in NFSV4 mounted volume. I tried in local 
file system in Solaris and the behavior was same.
 


<machine details>
bash-3.00$ uname -a
SunOS m/c name 5.10 Generic_120012-14 i86pc i386 i86pc
</machine details>

<begin>
1)
bash-3.00$ touch testfile1
bash-3.00$ chmod 777 testfile1
bash-3.00$ ls -l testfile1
-rwxrwxrwx   1 rg157576 staff          0 Jun 10 14:55 testfile1
bash-3.00$ $jdk/java NamedTest testfile1
new value hello

2)
bash-3.00$ chmod 400 testfile1
bash-3.00$ ls -l testfile1
-r--------   1 rg157576 staff          0 Jun 10 14:56 testfile1

bash-3.00$ $jdk/java NamedTest testfile1
new value hello
bash-3.00$ runat testfile1 /bin/sh
$ ls -l
total 4
-rwxrwxrwx   1 rg157576 staff          5 Jun 10 14:56 attr.2
-rwxrwxrwx   1 rg157576 staff          5 Jun 10 14:58 attr.3
3)
$ chmod 400 attr.3
$ exit
bash-3.00$ $jdk/java NamedTest testfile1
Exception in thread "main" java.nio.file.FileSystemException: testfile1: 
Unable to get write extended attribute 'attr.3': Permission denied
        at 
sun.nio.fs.SolarisNamedAttributeView.write(SolarisNamedAttributeView.java:204)
        at NamedTest.main(NamedTest.java:13)
bash-3.00$ $jdk/java NamedTest testfile1
new value hello
bash-3.00$ runat testfile1 /bin/sh
$ ls -l
total 6
-rwxrwxrwx   1 rg157576 staff          5 Jun 10 14:56 attr.2
-r--------   1 rg157576 staff          5 Jun 10 14:58 attr.3
-rwxrwxrwx   1 rg157576 staff          5 Jun 10 15:00 attr.4

bash-3.00$ ls -l testfile1
-r--------   1 rg157576 staff          0 Jun 10 14:56 testfile1

<end>
<code>
bash-3.00$ cat NamedTest.java
import java.nio.ByteBuffer;
import java.nio.file.*;
import java.nio.file.attribute.*;

public class NamedTest {
    public static void main(String... args) throws Exception {
       Path path = Path.get(args[0]);
       ByteBuffer bb =ByteBuffer.allocate(20);
      NamedAttributeView nav = 
path.newFileAttributeView(NamedAttributeView.class,true);  
      ByteBuffer bb1 = ByteBuffer.wrap("hello".getBytes());
      nav.write("attr.4",bb1);
      ByteBuffer bb2 = ByteBuffer.allocate(20);
      nav.read("attr.4",bb2);
     System.out.println("new value " + new String(bb2.array()));
   }
}
</code>

Thanks
Rajendra.