--- a/hotspot/src/os/linux/vm/os_linux.cpp	Thu Dec 16 12:56:51 2010 -0800
+++ b/hotspot/src/os/linux/vm/os_linux.cpp	Thu Dec 16 20:57:03 2010 -0500
@@ -115,6 +115,7 @@
 # include <link.h>
 # include <stdint.h>
 # include <inttypes.h>
+# include <sys/ioctl.h>
 
 #define MAX_PATH    (2 * K)
 
@@ -4433,6 +4434,15 @@
   return 1;
 }
 
+int os::socket_available(int fd, jint *pbytes) {
+  // Linux doc says EINTR not returned, unlike Solaris
+  int ret = ::ioctl(fd, FIONREAD, pbytes);
+
+  //%% note ioctl can return 0 when successful, JVM_SocketAvailable
+  // is expected to return 0 on failure and 1 on success to the jdk.
+  return (ret < 0) ? 0 : 1;
+}
+
 // Map a block of memory.
 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
                      char *addr, size_t bytes, bool read_only,