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 /*

  * Copyright (c) 2014, 2015, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

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 #ifndef SHARE_VM_CLASSFILE_SHAREDPATHSMISCINFO_HPP

 #define SHARE_VM_CLASSFILE_SHAREDPATHSMISCINFO_HPP

 #include "runtime/os.hpp"

 // During dumping time, when processing class paths, we build up the dump-time

 // classpath. The JAR files that exist are stored in the list ClassLoader::_first_entry.

 // However, we need to store other "misc" information for run-time checking, such as

 //

 // + The values of Arguments::get_sysclasspath() used during dumping.

 //

 // + The meta-index file(s) used during dumping (incl modification time and size)

 //

 // + The class path elements specified during dumping but did not exist --

 //   these elements must also be specified at run time, and they also must not

 //   exist at run time.

 //

 // These misc items are stored in a linear buffer in SharedPathsMiscInfo.

 // The storage format is stream oriented to minimize its size.

 //

 // When writing the information to the archive file, SharedPathsMiscInfo is stored in

 // the archive file header. At run-time, this information is used only during initialization

 // (accessed using read() instead of mmap()), and is deallocated afterwards to save space.

 //

 // The SharedPathsMiscInfo class is used for both creating the the information (during

 // dumping time) and validation (at run time). Different constructors are used in the

 // two situations. See below.

 class SharedPathsMiscInfo : public CHeapObj<mtClass> {

 protected:

   char* _buf_start;

   char* _cur_ptr;

   char* _end_ptr;

   int   _buf_size;

   bool  _allocated;   // was _buf_start allocated by me?

   void ensure_size(size_t needed_bytes);

   void add_path(const char* path, int type);

   void write(const void* ptr, size_t size);

   bool read(void* ptr, size_t size);

   static void trace_class_path(const char* msg, const char* name = NULL) {

     ClassLoader::trace_class_path(tty, msg, name);

   }

 protected:

   static bool fail(const char* msg, const char* name = NULL);

   virtual bool check(jint type, const char* path);

 public:

   enum {

     INITIAL_BUF_SIZE = 128

   };

   // This constructor is used when creating the misc information (during dump)

   SharedPathsMiscInfo() {

     _buf_size = INITIAL_BUF_SIZE;

     _cur_ptr = _buf_start = NEW_C_HEAP_ARRAY(char, _buf_size, mtClass);

     _allocated = true;

   }

   // This constructor is used when validating the misc info (during run time)

   SharedPathsMiscInfo(char *buff, int size) {

     _cur_ptr = _buf_start = buff;

     _end_ptr = _buf_start + size;

     _buf_size = size;

     _allocated = false;

   }

   ~SharedPathsMiscInfo() {

     if (_allocated) {

       FREE_C_HEAP_ARRAY(char, _buf_start, mtClass);

     }

   }

   int get_used_bytes() {

     return _cur_ptr - _buf_start;

   }

   void* buffer() {

     return _buf_start;

   }

   // writing --

   // The path must not exist at run-time

   void add_nonexist_path(const char* path) {

     add_path(path, NON_EXIST);

   }

   // The path must exist and have required size and modification time

   void add_required_file(const char* path) {

     add_path(path, REQUIRED);

     struct stat st;

     if (os::stat(path, &st) != 0) {

       assert(0, "sanity");

       ClassLoader::exit_with_path_failure("failed to os::stat(%s)", path); // should not happen

     }

     write_time(st.st_mtime);

     write_long(st.st_size);

   }

   // The path must exist, and must contain exactly <num_entries> files/dirs

   void add_boot_classpath(const char* path) {

     add_path(path, BOOT);

   }

   int write_jint(jint num) {

     write(&num, sizeof(num));

     return 0;

   }

   void write_time(time_t t) {

     write(&t, sizeof(t));

   }

   void write_long(long l) {

     write(&l, sizeof(l));

   }

   bool dump_to_file(int fd) {

     int n = get_used_bytes();

     return (os::write(fd, _buf_start, n) == (size_t)n);

   }

   // reading --

   enum {

     BOOT      = 1,

     NON_EXIST = 2,

     REQUIRED  = 3

   };

   virtual const char* type_name(int type) {

     switch (type) {

     case BOOT:      return "BOOT";

     case NON_EXIST: return "NON_EXIST";

     case REQUIRED:  return "REQUIRED";

     default:        ShouldNotReachHere(); return "?";

     }

   }

   virtual void print_path(outputStream* out, int type, const char* path) {

     switch (type) {

     case BOOT:

       out->print("Expecting -Dsun.boot.class.path=%s", path);

       break;

     case NON_EXIST:

       out->print("Expecting that %s does not exist", path);

       break;

     case REQUIRED:

       out->print("Expecting that file %s must exist and is not altered", path);

       break;

     default:

       ShouldNotReachHere();

     }

   }

   bool check();

   bool read_jint(jint *ptr) {

     return read(ptr, sizeof(jint));

   }

   bool read_long(long *ptr) {

     return read(ptr, sizeof(long));

   }

   bool read_time(time_t *ptr) {

     return read(ptr, sizeof(time_t));

   }

 };

 #endif // SHARE_VM_CLASSFILE_SHAREDPATHSMISCINFO_HPP