1 files changed, 34 insertions, 0 deletions
diff --git a/libjava/java/io/natFileDescriptorPosix.cc b/libjava/java/io/natFileDescriptorPosix.cc
index bfe00093f40..fb11d6262d1 100644
--- a/libjava/java/io/natFileDescriptorPosix.cc
+++ b/libjava/java/io/natFileDescriptorPosix.cc
@@ -17,6 +17,8 @@ details.  */
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/param.h>
+#include <sys/socket.h>
+#include <fcntl.h>
 
 #ifdef HAVE_SYS_IOCTL_H
 #define BSD_COMP /* Get FIONREAD on Solaris2. */
@@ -189,6 +191,38 @@ java::io::FileDescriptor::close (void)
     throw new IOException (JvNewStringLatin1 (strerror (errno)));
 }
 
+void
+java::io::FileDescriptor::setLength (jlong pos)
+{
+  struct stat sb;
+  off_t orig;
+
+  if (::fstat (fd, &sb))
+    throw new IOException (JvNewStringLatin1 (strerror (errno)));
+
+  if ((jlong) sb.st_size == pos) 
+    return;
+
+  orig = ::lseek (fd, (off_t) 0, SEEK_CUR);
+  if (orig == -1)
+    throw new IOException (JvNewStringLatin1 (strerror (errno)));
+
+  // If the file is too short, we extend it.  We can't rely on
+  // ftruncate() extending the file.  So we lseek() to 1 byte less
+  // than we want, and then we write a single byte at the end.
+  if ((jlong) sb.st_size < pos)
+    {
+      if (::lseek (fd, (off_t) (pos - 1), SEEK_SET) == -1)
+	throw new IOException (JvNewStringLatin1 (strerror (errno)));
+      char out = '\0';
+      int r = ::write (fd, &out, 1);
+      if (r <= 0 || ::lseek (fd, orig, SEEK_SET) == -1)
+	throw new IOException (JvNewStringLatin1 (strerror (errno)));
+    }
+  else if (::ftruncate (fd, (off_t) pos))
+    throw new IOException (JvNewStringLatin1 (strerror (errno)));
+}
+
 jint
 java::io::FileDescriptor::seek (jlong pos, jint whence, jboolean eof_trunc)
 {