/*

 * Copyright (c) 2003, 2013, 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

 * questions.

 *

 */

#include "precompiled.hpp"

#include "classfile/classLoader.hpp"

#include "classfile/symbolTable.hpp"

#include "classfile/altHashing.hpp"

#include "memory/filemap.hpp"

#include "runtime/arguments.hpp"

#include "runtime/java.hpp"

#include "runtime/os.hpp"

#include "services/memTracker.hpp"

#include "utilities/defaultStream.hpp"

# include <sys/stat.h>

# include <errno.h>

#ifndef O_BINARY       // if defined (Win32) use binary files.

#define O_BINARY 0     // otherwise do nothing.

#endif

extern address JVM_FunctionAtStart();

extern address JVM_FunctionAtEnd();

// Complain and stop. All error conditions occurring during the writing of

// an archive file should stop the process.  Unrecoverable errors during

// the reading of the archive file should stop the process.

static void fail(const char *msg, va_list ap) {

  // This occurs very early during initialization: tty is not initialized.

  jio_fprintf(defaultStream::error_stream(),

              "An error has occurred while processing the"

              " shared archive file.\n");

  jio_vfprintf(defaultStream::error_stream(), msg, ap);

  jio_fprintf(defaultStream::error_stream(), "\n");

  // Do not change the text of the below message because some tests check for it.

  vm_exit_during_initialization("Unable to use shared archive.", NULL);

}

void FileMapInfo::fail_stop(const char *msg, ...) {

        va_list ap;

  va_start(ap, msg);

  fail(msg, ap);        // Never returns.

  va_end(ap);           // for completeness.

}

// Complain and continue.  Recoverable errors during the reading of the

// archive file may continue (with sharing disabled).

//

// If we continue, then disable shared spaces and close the file.

void FileMapInfo::fail_continue(const char *msg, ...) {

  va_list ap;

  va_start(ap, msg);

  if (RequireSharedSpaces) {

    fail(msg, ap);

  }

  va_end(ap);

  UseSharedSpaces = false;

  close();

}

// Fill in the fileMapInfo structure with data about this VM instance.

// This method copies the vm version info into header_version.  If the version is too

// long then a truncated version, which has a hash code appended to it, is copied.

//

// Using a template enables this method to verify that header_version is an array of

// length JVM_IDENT_MAX.  This ensures that the code that writes to the CDS file and

// the code that reads the CDS file will both use the same size buffer.  Hence, will

// use identical truncation.  This is necessary for matching of truncated versions.

template <int N> static void get_header_version(char (&header_version) [N]) {

  assert(N == JVM_IDENT_MAX, "Bad header_version size");

  const char *vm_version = VM_Version::internal_vm_info_string();

  const int version_len = (int)strlen(vm_version);

  if (version_len < (JVM_IDENT_MAX-1)) {

    strcpy(header_version, vm_version);

  } else {

    // Get the hash value.  Use a static seed because the hash needs to return the same

    // value over multiple jvm invocations.

    unsigned int hash = AltHashing::murmur3_32(8191, (const jbyte*)vm_version, version_len);

    // Truncate the ident, saving room for the 8 hex character hash value.

    strncpy(header_version, vm_version, JVM_IDENT_MAX-9);

    // Append the hash code as eight hex digits.

    sprintf(&header_version[JVM_IDENT_MAX-9], "%08x", hash);

    header_version[JVM_IDENT_MAX-1] = 0;  // Null terminate.

  }

}

void FileMapInfo::populate_header(size_t alignment) {

  _header._magic = 0xf00baba2;

  _header._version = _current_version;

  _header._alignment = alignment;

  _header._obj_alignment = ObjectAlignmentInBytes;

  // The following fields are for sanity checks for whether this archive

  // will function correctly with this JVM and the bootclasspath it's

  // invoked with.

  // JVM version string ... changes on each build.

  get_header_version(_header._jvm_ident);

  // Build checks on classpath and jar files

  _header._num_jars = 0;

  ClassPathEntry *cpe = ClassLoader::classpath_entry(0);

  for ( ; cpe != NULL; cpe = cpe->next()) {

    if (cpe->is_jar_file()) {

      if (_header._num_jars >= JVM_SHARED_JARS_MAX) {

        fail_stop("Too many jar files to share.", NULL);

      }

      // Jar file - record timestamp and file size.

      struct stat st;

      const char *path = cpe->name();

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

        // If we can't access a jar file in the boot path, then we can't

        // make assumptions about where classes get loaded from.

        fail_stop("Unable to open jar file %s.", path);

      }

      _header._jar[_header._num_jars]._timestamp = st.st_mtime;

      _header._jar[_header._num_jars]._filesize = st.st_size;

      _header._num_jars++;

    } else {

      // If directories appear in boot classpath, they must be empty to

      // avoid having to verify each individual class file.

      const char* name = ((ClassPathDirEntry*)cpe)->name();

      if (!os::dir_is_empty(name)) {

        fail_stop("Boot classpath directory %s is not empty.", name);

      }

    }

  }

}

// Read the FileMapInfo information from the file.

bool FileMapInfo::init_from_file(int fd) {

  size_t n = read(fd, &_header, sizeof(struct FileMapHeader));

  if (n != sizeof(struct FileMapHeader)) {

    fail_continue("Unable to read the file header.");

    return false;

  }

  if (_header._version != current_version()) {

    fail_continue("The shared archive file has the wrong version.");

    return false;

  }

  _file_offset = (long)n;

  return true;

}

// Read the FileMapInfo information from the file.

bool FileMapInfo::open_for_read() {

  _full_path = Arguments::GetSharedArchivePath();

  int fd = open(_full_path, O_RDONLY | O_BINARY, 0);

  if (fd < 0) {

    if (errno == ENOENT) {

      // Not locating the shared archive is ok.

      fail_continue("Specified shared archive not found.");

    } else {

      fail_continue("Failed to open shared archive file (%s).",

                    strerror(errno));

    }

    return false;

  }

  _fd = fd;

  _file_open = true;

  return true;

}

// Write the FileMapInfo information to the file.

void FileMapInfo::open_for_write() {

 _full_path = Arguments::GetSharedArchivePath();

  if (PrintSharedSpaces) {

    tty->print_cr("Dumping shared data to file: ");

    tty->print_cr("   %s", _full_path);

  }

#ifdef _WINDOWS  // On Windows, need WRITE permission to remove the file.

  chmod(_full_path, _S_IREAD | _S_IWRITE);

#endif

  // Use remove() to delete the existing file because, on Unix, this will

  // allow processes that have it open continued access to the file.

  remove(_full_path);

  int fd = open(_full_path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0444);

  if (fd < 0) {

    fail_stop("Unable to create shared archive file %s.", _full_path);

  }

  _fd = fd;

  _file_offset = 0;

  _file_open = true;

}

// Write the header to the file, seek to the next allocation boundary.

void FileMapInfo::write_header() {

  write_bytes_aligned(&_header, sizeof(FileMapHeader));

}

// Dump shared spaces to file.

void FileMapInfo::write_space(int i, Metaspace* space, bool read_only) {

  align_file_position();

  size_t used = space->used_bytes_slow(Metaspace::NonClassType);

  size_t capacity = space->capacity_bytes_slow(Metaspace::NonClassType);

  struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];

  write_region(i, (char*)space->bottom(), used, capacity, read_only, false);

}

// Dump region to file.

void FileMapInfo::write_region(int region, char* base, size_t size,

                               size_t capacity, bool read_only,

                               bool allow_exec) {

  struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[region];

  if (_file_open) {

    guarantee(si->_file_offset == _file_offset, "file offset mismatch.");

    if (PrintSharedSpaces) {

      tty->print_cr("Shared file region %d: 0x%6x bytes, addr " INTPTR_FORMAT

                    " file offset 0x%6x", region, size, base, _file_offset);

    }

  } else {

    si->_file_offset = _file_offset;

  }

  si->_base = base;

  si->_used = size;

  si->_capacity = capacity;

  si->_read_only = read_only;

  si->_allow_exec = allow_exec;

  write_bytes_aligned(base, (int)size);

}

// Dump bytes to file -- at the current file position.

void FileMapInfo::write_bytes(const void* buffer, int nbytes) {

  if (_file_open) {

    int n = ::write(_fd, buffer, nbytes);

    if (n != nbytes) {

      // It is dangerous to leave the corrupted shared archive file around,

      // close and remove the file. See bug 6372906.

      close();

      remove(_full_path);

      fail_stop("Unable to write to shared archive file.", NULL);

    }

  }

  _file_offset += nbytes;

}

// Align file position to an allocation unit boundary.

void FileMapInfo::align_file_position() {

  long new_file_offset = align_size_up(_file_offset, os::vm_allocation_granularity());

  if (new_file_offset != _file_offset) {

    _file_offset = new_file_offset;

    if (_file_open) {

      // Seek one byte back from the target and write a byte to insure

      // that the written file is the correct length.

      _file_offset -= 1;

      if (lseek(_fd, _file_offset, SEEK_SET) < 0) {

        fail_stop("Unable to seek.", NULL);

      }

      char zero = 0;

      write_bytes(&zero, 1);

    }

  }

}

// Dump bytes to file -- at the current file position.

void FileMapInfo::write_bytes_aligned(const void* buffer, int nbytes) {

  align_file_position();

  write_bytes(buffer, nbytes);

  align_file_position();

}

// Close the shared archive file.  This does NOT unmap mapped regions.

void FileMapInfo::close() {

  if (_file_open) {

    if (::close(_fd) < 0) {

      fail_stop("Unable to close the shared archive file.");

    }

    _file_open = false;

    _fd = -1;

  }

}

// JVM/TI RedefineClasses() support:

// Remap the shared readonly space to shared readwrite, private.

bool FileMapInfo::remap_shared_readonly_as_readwrite() {

  struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0];

  if (!si->_read_only) {

    // the space is already readwrite so we are done

    return true;

  }

  size_t used = si->_used;

  size_t size = align_size_up(used, os::vm_allocation_granularity());

  if (!open_for_read()) {

    return false;

  }

  char *base = os::remap_memory(_fd, _full_path, si->_file_offset,

                                si->_base, size, false /* !read_only */,

                                si->_allow_exec);

  close();

  if (base == NULL) {

    fail_continue("Unable to remap shared readonly space (errno=%d).", errno);

    return false;

  }

  if (base != si->_base) {

    fail_continue("Unable to remap shared readonly space at required address.");

    return false;

  }

  si->_read_only = false;

  return true;

}

// Map the whole region at once, assumed to be allocated contiguously.

ReservedSpace FileMapInfo::reserve_shared_memory() {

  struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[0];

  char* requested_addr = si->_base;

  size_t size = FileMapInfo::shared_spaces_size();

  // Reserve the space first, then map otherwise map will go right over some

  // other reserved memory (like the code cache).

  ReservedSpace rs(size, os::vm_allocation_granularity(), false, requested_addr);

  if (!rs.is_reserved()) {

    fail_continue(err_msg("Unable to reserve shared space at required address " INTPTR_FORMAT, requested_addr));

    return rs;

  }

  // the reserved virtual memory is for mapping class data sharing archive

  MemTracker::record_virtual_memory_type((address)rs.base(), mtClassShared);

  return rs;

}

// Memory map a region in the address space.

static const char* shared_region_name[] = { "ReadOnly", "ReadWrite", "MiscData", "MiscCode"};

char* FileMapInfo::map_region(int i) {

  struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];

  size_t used = si->_used;

  size_t alignment = os::vm_allocation_granularity();

  size_t size = align_size_up(used, alignment);

  char *requested_addr = si->_base;

  // map the contents of the CDS archive in this memory

  char *base = os::map_memory(_fd, _full_path, si->_file_offset,

                              requested_addr, size, si->_read_only,

                              si->_allow_exec);

  if (base == NULL || base != si->_base) {

    fail_continue(err_msg("Unable to map %s shared space at required address.", shared_region_name[i]));

    return NULL;

  }

#ifdef _WINDOWS

  // This call is Windows-only because the memory_type gets recorded for the other platforms

  // in method FileMapInfo::reserve_shared_memory(), which is not called on Windows.

  MemTracker::record_virtual_memory_type((address)base, mtClassShared);

#endif

  return base;

}

// Unmap a memory region in the address space.

void FileMapInfo::unmap_region(int i) {

  struct FileMapInfo::FileMapHeader::space_info* si = &_header._space[i];

  size_t used = si->_used;

  size_t size = align_size_up(used, os::vm_allocation_granularity());

  if (!os::unmap_memory(si->_base, size)) {

    fail_stop("Unable to unmap shared space.");

  }

}

void FileMapInfo::assert_mark(bool check) {

  if (!check) {

    fail_stop("Mark mismatch while restoring from shared file.", NULL);

  }

}

FileMapInfo* FileMapInfo::_current_info = NULL;

// Open the shared archive file, read and validate the header

// information (version, boot classpath, etc.).  If initialization

// fails, shared spaces are disabled and the file is closed. [See

// fail_continue.]

bool FileMapInfo::initialize() {

  assert(UseSharedSpaces, "UseSharedSpaces expected.");

  if (JvmtiExport::can_modify_any_class() || JvmtiExport::can_walk_any_space()) {

    fail_continue("Tool agent requires sharing to be disabled.");

    return false;

  }

  if (!open_for_read()) {

    return false;

  }

  init_from_file(_fd);

  if (!validate()) {

    return false;

  }

  SharedReadOnlySize =  _header._space[0]._capacity;

  SharedReadWriteSize = _header._space[1]._capacity;

  SharedMiscDataSize =  _header._space[2]._capacity;

  SharedMiscCodeSize =  _header._space[3]._capacity;

  return true;

}

bool FileMapInfo::validate() {

  if (_header._version != current_version()) {

    fail_continue("The shared archive file is the wrong version.");

    return false;

  }

  if (_header._magic != (int)0xf00baba2) {

    fail_continue("The shared archive file has a bad magic number.");

    return false;

  }

  char header_version[JVM_IDENT_MAX];

  get_header_version(header_version);

  if (strncmp(_header._jvm_ident, header_version, JVM_IDENT_MAX-1) != 0) {

    fail_continue("The shared archive file was created by a different"

                  " version or build of HotSpot.");

    return false;

  }

  if (_header._obj_alignment != ObjectAlignmentInBytes) {

    fail_continue("The shared archive file's ObjectAlignmentInBytes of %d"

                  " does not equal the current ObjectAlignmentInBytes of %d.",

                  _header._obj_alignment, ObjectAlignmentInBytes);

    return false;

  }

  // Cannot verify interpreter yet, as it can only be created after the GC

  // heap has been initialized.

  if (_header._num_jars >= JVM_SHARED_JARS_MAX) {

    fail_continue("Too many jar files to share.");

    return false;

  }

  // Build checks on classpath and jar files

  int num_jars_now = 0;

  ClassPathEntry *cpe = ClassLoader::classpath_entry(0);

  for ( ; cpe != NULL; cpe = cpe->next()) {

    if (cpe->is_jar_file()) {

      if (num_jars_now < _header._num_jars) {

        // Jar file - verify timestamp and file size.

        struct stat st;

        const char *path = cpe->name();

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

          fail_continue("Unable to open jar file %s.", path);

          return false;

        }

        if (_header._jar[num_jars_now]._timestamp != st.st_mtime ||

            _header._jar[num_jars_now]._filesize != st.st_size) {

          fail_continue("A jar file is not the one used while building"

                        " the shared archive file.");

          return false;

        }

      }

      ++num_jars_now;