*** old/src/hotspot/os/windows/os_windows.cpp	Wed Oct 25 11:01:40 2017
--- new/src/hotspot/os/windows/os_windows.cpp	Wed Oct 25 11:01:39 2017

*** 4058,4076 ****
--- 4058,4146 ----
                        PAGE_READONLY, &old_status)) {
      fatal("Could not enable polling page");
    }
  }
  
+ // combine the high and low DWORD into a ULONGLONG
+ static ULONGLONG eval_find_data(DWORD high_word, DWORD low_word) {
+   ULONGLONG value = high_word;
+   value <<= sizeof(high_word) * 8;
+   value |= low_word;
+   return value;
+ }
+ 
+ // setup the struct stat using the data from WIN32_FIND_DATAW structure
+ static void setup_stat(struct stat* sbuf, WIN32_FIND_DATAW find_data) {
+   sbuf->st_size = (_off_t)eval_find_data(find_data.nFileSizeHigh, find_data.nFileSizeLow);
+   sbuf->st_mtime = eval_find_data(find_data.ftLastWriteTime.dwHighDateTime,
+                                   find_data.ftLastWriteTime.dwLowDateTime);
+   sbuf->st_ctime = eval_find_data(find_data.ftCreationTime.dwHighDateTime,
+                                   find_data.ftCreationTime.dwLowDateTime);
+   sbuf->st_atime = eval_find_data(find_data.ftLastAccessTime.dwHighDateTime,
+                                   find_data.ftLastAccessTime.dwLowDateTime);
+   if (find_data.dwFileAttributes == FILE_ATTRIBUTE_DIRECTORY) {
+     sbuf->st_mode |= S_IFDIR;
+   }
+   if (find_data.dwFileAttributes == FILE_ATTRIBUTE_NORMAL) {
+     sbuf->st_mode |= S_IFREG;
+   }
+ }
+ 
+ // The following function is adapted from java.base/windows/native/libjava/canonicalize_md.c
+ // copy \\?\ or \\?\UNC\ to the front of path
+ static void prefixed_path(WCHAR* wpath, size_t pathlen) {
+   if (wpath[0] == L'\\' && wpath[1] == L'\\') {
+     /* if it already has a \\?\ don't do the prefix */
+     if (!(wpath[2] == L'?' && wpath[3] == L'\\')) {
+       /* only UNC pathname includes double slashes here */
+       ::wmemmove(wpath + 7, wpath + 1, pathlen - 1);
+       ::wmemcpy_s(wpath, pathlen, L"\\\\?\\UNC", 7);
+       wpath[pathlen + 6] = L'\0';
+     }
+   }
+   else {
+     ::wmemmove(wpath + 4, wpath, pathlen);
+     ::wmemcpy_s(wpath, pathlen, L"\\\\?\\", 4);
+     wpath[pathlen + 4] = L'\0';
+   }
+ }
  
  int os::stat(const char *path, struct stat *sbuf) {
!   char pathbuf[MAX_PATH];
    if (strlen(path) > MAX_PATH - 1) {
      errno = ENAMETOOLONG;
!   size_t path_len = strlen(path) + 1;
+   char* pathbuf = (char*)os::malloc(path_len * sizeof(char), mtInternal);
+   if (pathbuf == NULL) {
+     errno = ENOMEM;
      return -1;
    }
    os::native_path(strcpy(pathbuf, path));
-   int ret = ::stat(pathbuf, sbuf);
+   if (strlen(path) < MAX_PATH) {
+     ret = ::stat(pathbuf, sbuf);
+   } else {
+     WCHAR* wpathbuf = (WCHAR*)os::malloc((path_len + 10) * sizeof (WCHAR), mtInternal);
+     if (wpathbuf == NULL) {
+       os::free(pathbuf);
+       errno = ENOMEM;
+       return -1;
+     }
+     size_t converted_chars = 0;
+     ::mbstowcs_s(&converted_chars, wpathbuf, path_len + 10, pathbuf, strlen(path));
+     prefixed_path(wpathbuf, strlen(path));
+     WIN32_FIND_DATAW find_data;
+     HANDLE h_find;
+     h_find = ::FindFirstFileW(wpathbuf, &find_data);
+     if (h_find == INVALID_HANDLE_VALUE) {
+       errno = ::GetLastError();
+       os::free(wpathbuf);
+       ret = -1;
+     } else {
+       setup_stat(sbuf, find_data);
+       ret = 0;
+       ::FindClose(h_find);
+     }
+     os::free(wpathbuf);
+   }
    if (sbuf != NULL && UseUTCFileTimestamp) {
      // Fix for 6539723.  st_mtime returned from stat() is dependent on
      // the system timezone and so can return different values for the
      // same file if/when daylight savings time changes.  This adjustment
      // makes sure the same timestamp is returned regardless of the TZ.

*** 4093,4102 ****
--- 4163,4173 ----
      DWORD tzid = GetTimeZoneInformation(&tz);
      int daylightBias =
        (tzid == TIME_ZONE_ID_DAYLIGHT) ? tz.DaylightBias : tz.StandardBias;
      sbuf->st_mtime += (tz.Bias + daylightBias) * 60;
    }
+   os::free(pathbuf);
    return ret;
  }
  
  
  #define FT2INT64(ft) \

*** 4205,4222 ****
--- 4276,4313 ----
  
  // This method is a slightly reworked copy of JDK's sysOpen
  // from src/windows/hpi/src/sys_api_md.c
  
  int os::open(const char *path, int oflag, int mode) {
!   char pathbuf[MAX_PATH];
  
!   if (strlen(path) > MAX_PATH - 1) {
!     errno = ENAMETOOLONG;
!   size_t path_len = strlen(path) + 1;
+   char* pathbuf = (char*)os::malloc(path_len * sizeof(char), mtInternal);
!   if (pathbuf == NULL) {
!     errno = ENOMEM;
      return -1;
    }
    os::native_path(strcpy(pathbuf, path));
!   return ::open(pathbuf, oflag | O_BINARY | O_NOINHERIT, mode);
!   int ret;
+   if (strlen(path) < MAX_PATH) {
+     ret = ::open(pathbuf, oflag | O_BINARY | O_NOINHERIT, mode);
+   } else {
+     WCHAR* wpathbuf = (WCHAR*)os::malloc((path_len + 10) * sizeof (WCHAR), mtInternal);
+     if (wpathbuf == NULL) {
+       os::free(pathbuf);
+       errno = ENOMEM;
+       return -1;
+     }
+     size_t converted_chars = 0;
+     ::mbstowcs_s(&converted_chars, wpathbuf, path_len + 10, pathbuf, strlen(path));
+     prefixed_path(wpathbuf, strlen(path));
+     ret = ::_wopen(wpathbuf, oflag | O_BINARY | O_NOINHERIT, mode);
+     if (ret == -1) {
+       errno = ::GetLastError();
+     }
+     os::free(wpathbuf);
+   }
+   os::free(pathbuf);
+   return ret;
  }
  
  FILE* os::open(int fd, const char* mode) {
    return ::_fdopen(fd, mode);
  }