*** old/src/share/vm/runtime/arguments.cpp	Wed Sep  4 19:27:24 2013
--- new/src/share/vm/runtime/arguments.cpp	Wed Sep  4 19:27:24 2013

*** 1848,1858 ****
--- 1848,1858 ----
    if (UseGCLogFileRotation) {
      if ((Arguments::gc_log_filename() == NULL) ||
          (NumberOfGCLogFiles == 0)  ||
          (GCLogFileSize == 0)) {
        jio_fprintf(defaultStream::output_stream(),
!                   "To enable GC log rotation, use -Xloggc:<filename> -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=<num_of_files> -XX:GCLogFileSize=<num_of_size>[k|K|m|M|g|G]\n"
                    "where num_of_file > 0 and num_of_size > 0\n"
                    "GC log rotation is turned off\n");
        UseGCLogFileRotation = false;
      }
    }

*** 1862,1871 ****
--- 1862,1907 ----
          jio_fprintf(defaultStream::output_stream(),
                      "GCLogFileSize changed to minimum 8K\n");
    }
  }
  
+ // This function is called for -Xloggc:<filename>, it can be used 
+ // to check if a given file name(or string) conforms to the following
+ // specification: 
+ // A valid string only contains "[A-Z][a-z][0-9].-_%[p|t]"
+ // %p and %t only allowed once.
+ bool is_filename_valid(const char *file_name) {
+   const char* p = file_name;
+   int count_p = 0;
+   int count_t = 0;
+   while (*p != '\0') {
+     if ((*p >= '0' && *p <= '9') ||
+         (*p >= 'A' && *p <= 'Z') ||
+         (*p >= 'a' && *p <= 'z') ||
+          *p == '-'               ||
+          *p == '_'               ||
+          *p == '.') {
+        p++;
+        continue;
+     }
+     if (*p == '%') {
+       if(*(p + 1) == 'p') {
+         p += 2;
+         count_p ++;
+         continue;
+       }
+       if (*(p + 1) == 't') {
+         p += 2;
+         count_t ++;
+         continue;
+       }
+     }
+     return false;
+   }
+   return count_p < 2 && count_t < 2;
+ }
+ 
  // Check consistency of GC selection
  bool Arguments::check_gc_consistency() {
    check_gclog_consistency();
    bool status = true;
    // Ensure that the user has not selected conflicting sets

*** 2815,2824 ****
--- 2851,2866 ----
      } else if (match_option(option, "-Xloggc:", &tail)) {
        // Redirect GC output to the file. -Xloggc:<filename>
        // ostream_init_log(), when called will use this filename
        // to initialize a fileStream.
        _gc_log_filename = strdup(tail);
+      if (!is_filename_valid(_gc_log_filename)) {
+        jio_fprintf(defaultStream::output_stream(),
+                   "Filename can only cantain [A-Z][a-z][0-9]-_.%%[p|t]\n"
+                   "%%p and %%t can only show up once\n" );
+         return JNI_EINVAL;
+       }
        FLAG_SET_CMDLINE(bool, PrintGC, true);
        FLAG_SET_CMDLINE(bool, PrintGCTimeStamps, true);
  
      // JNI hooks
      } else if (match_option(option, "-Xcheck", &tail)) {