Index: jruby/ext/posix/Timeval.java
===================================================================
--- jruby/ext/posix/Timeval.java	(revision 0)
+++ jruby/ext/posix/Timeval.java	(revision 0)
@@ -0,0 +1,5 @@
+package org.jruby.ext.posix;
+
+public interface Timeval {
+    public void setMicroseconds(long time);
+}
Index: jruby/ext/posix/POSIX.java
===================================================================
--- jruby/ext/posix/POSIX.java	(revision 213)
+++ jruby/ext/posix/POSIX.java	(working copy)
@@ -54,6 +54,7 @@
     public FileStat stat(String path);
     public int symlink(String oldpath,String newpath);
     public int umask(int mask);
+    public int utimes(String path, long atime, long mtime);
     public int waitpid(int pid, int[] status, int flags);
     public int wait(int[] status);
 }
Index: jruby/ext/posix/BaseNativePOSIX.java
===================================================================
--- jruby/ext/posix/BaseNativePOSIX.java	(revision 213)
+++ jruby/ext/posix/BaseNativePOSIX.java	(working copy)
@@ -204,6 +204,13 @@
     public int umask(int mask) {
         return libc.umask(mask);
     }
+
+    public int utimes(String path, long atime, long mtime) {
+	Timeval[] times = ((Timeval[])new DefaultNativeTimeval().toArray(2));
+	times[0].setMicroseconds(atime);
+	times[1].setMicroseconds(mtime);
+	return libc.utimes(path, times);
+    }
     
     public int fork() {
         return libc.fork();
Index: jruby/ext/posix/JavaPOSIX.java
===================================================================
--- jruby/ext/posix/JavaPOSIX.java	(revision 213)
+++ jruby/ext/posix/JavaPOSIX.java	(working copy)
@@ -211,6 +211,11 @@
         // libc methods.  
         return 0;
     }
+
+    public int utimes(String path, long atime, long mtime) {
+	new java.io.File(path).setLastModified(mtime);
+	return 0;
+    }
     
     public int wait(int[] status) {
         return unimplementedInt("wait");
Index: jruby/ext/posix/NativeTimeval.java
===================================================================
--- jruby/ext/posix/NativeTimeval.java	(revision 0)
+++ jruby/ext/posix/NativeTimeval.java	(revision 0)
@@ -0,0 +1,6 @@
+package org.jruby.ext.posix;
+
+import com.sun.jna.Structure;
+
+public abstract class NativeTimeval extends Structure implements Timeval {
+}
Index: jruby/ext/posix/LibC.java
===================================================================
--- jruby/ext/posix/LibC.java	(revision 213)
+++ jruby/ext/posix/LibC.java	(working copy)
@@ -76,6 +76,7 @@
     public int symlink(String oldpath,String newpath);
     public int readlink(String oldpath,ByteBuffer buffer,int len);
     public int umask(int mask);
+    public int utimes(String path, Timeval[] times);
     public int fork();
     public int waitpid(int pid, int[] status, int options);
     public int wait(int[] status);
Index: jruby/ext/posix/DefaultNativeTimeval.java
===================================================================
--- jruby/ext/posix/DefaultNativeTimeval.java	(revision 0)
+++ jruby/ext/posix/DefaultNativeTimeval.java	(revision 0)
@@ -0,0 +1,14 @@
+package org.jruby.ext.posix;
+
+public final class DefaultNativeTimeval extends NativeTimeval {
+    public int tv_sec;
+    public int tv_usec;
+
+    public DefaultNativeTimeval() {}
+
+    public void setMicroseconds(long time) {
+	tv_sec = (int)(time / 1000);
+	tv_usec = (int)(time % 1000);
+    }
+    
+}