src/hotspot/share/classfile/classLoaderExt.cpp

/*
 * Copyright (c) 2015, 2023, 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 "cds/cds_globals.hpp"
#include "cds/dynamicArchive.hpp"
#include "cds/filemap.hpp"
#include "cds/heapShared.hpp"
#include "classfile/classFileParser.hpp"
#include "classfile/classLoader.inline.hpp"
#include "classfile/classLoaderExt.hpp"
#include "classfile/classLoaderData.inline.hpp"
#include "classfile/classLoadInfo.hpp"
#include "classfile/klassFactory.hpp"
#include "classfile/modules.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmSymbols.hpp"
#include "gc/shared/collectedHeap.hpp"
#include "logging/log.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/resourceArea.hpp"
#include "oops/instanceKlass.hpp"
#include "oops/klass.inline.hpp"
#include "oops/oop.inline.hpp"
#include "oops/symbol.hpp"
#include "runtime/arguments.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/java.hpp"
#include "runtime/os.hpp"
#include "utilities/stringUtils.hpp"

jshort ClassLoaderExt::_app_class_paths_start_index = ClassLoaderExt::max_classpath_index;
jshort ClassLoaderExt::_app_module_paths_start_index = ClassLoaderExt::max_classpath_index;
jshort ClassLoaderExt::_max_used_path_index = 0;
bool ClassLoaderExt::_has_app_classes = false;
bool ClassLoaderExt::_has_platform_classes = false;
bool ClassLoaderExt::_has_non_jar_in_classpath = false;

void ClassLoaderExt::append_boot_classpath(ClassPathEntry* new_entry) {
  if (UseSharedSpaces) {
    warning("Sharing is only supported for boot loader classes because bootstrap classpath has been appended");
    FileMapInfo::current_info()->set_has_platform_or_app_classes(false);
    if (DynamicArchive::is_mapped()) {
      FileMapInfo::dynamic_info()->set_has_platform_or_app_classes(false);
    }
  }
  ClassLoader::add_to_boot_append_entries(new_entry);
}

void ClassLoaderExt::setup_app_search_path(JavaThread* current) {
  Arguments::assert_is_dumping_archive();
  int start_index = ClassLoader::num_boot_classpath_entries();
  _app_class_paths_start_index = checked_cast<jshort>(start_index);
  char* app_class_path = os::strdup_check_oom(Arguments::get_appclasspath(), mtClass);

  if (strcmp(app_class_path, ".") == 0) {
    // This doesn't make any sense, even for AppCDS, so let's skip it. We
    // don't want to throw an error here because -cp "." is usually assigned
    // by the launcher when classpath is not specified.
    trace_class_path("app loader class path (skipped)=", app_class_path);
  } else {
    trace_class_path("app loader class path=", app_class_path);
    ClassLoader::setup_app_search_path(current, app_class_path);
  }

  os::free(app_class_path);
}

void ClassLoaderExt::process_module_table(JavaThread* current, ModuleEntryTable* met) {
  ResourceMark rm(current);
  GrowableArray<char*>* module_paths = new GrowableArray<char*>(5);

  class ModulePathsGatherer : public ModuleClosure {
    JavaThread* _current;
    GrowableArray<char*>* _module_paths;
   public:
    ModulePathsGatherer(JavaThread* current, GrowableArray<char*>* module_paths) :
      _current(current), _module_paths(module_paths) {}
    void do_module(ModuleEntry* m) {
      char* path = m->location()->as_C_string();
      if (strncmp(path, "file:", 5) == 0) {
        path = ClassLoader::skip_uri_protocol(path);
        char* path_copy = NEW_RESOURCE_ARRAY(char, strlen(path) + 1);
        strcpy(path_copy, path);
        _module_paths->append(path_copy);
      }
    }
  };

  ModulePathsGatherer gatherer(current, module_paths);
  {
    MutexLocker ml(Module_lock);
    met->modules_do(&gatherer);
  }

  for (int i = 0; i < module_paths->length(); i++) {
    ClassLoader::setup_module_search_path(current, module_paths->at(i));
  }
}

void ClassLoaderExt::setup_module_paths(JavaThread* current) {
  Arguments::assert_is_dumping_archive();
  int start_index = ClassLoader::num_boot_classpath_entries() +
                    ClassLoader::num_app_classpath_entries();
  _app_module_paths_start_index = checked_cast<jshort>(start_index);
  Handle system_class_loader (current, SystemDictionary::java_system_loader());
  ModuleEntryTable* met = Modules::get_module_entry_table(system_class_loader);
  process_module_table(current, met);
}

char* ClassLoaderExt::read_manifest(JavaThread* current, ClassPathEntry* entry,
                                    jint *manifest_size, bool clean_text) {
  const char* name = "META-INF/MANIFEST.MF";
  char* manifest;
  jint size;

  assert(entry->is_jar_file(), "must be");
  manifest = (char*) ((ClassPathZipEntry*)entry )->open_entry(current, name, &size, true);

  if (manifest == nullptr) { // No Manifest
    *manifest_size = 0;
    return nullptr;
  }


  if (clean_text) {
    // See http://docs.oracle.com/javase/6/docs/technotes/guides/jar/jar.html#JAR%20Manifest
    // (1): replace all CR/LF and CR with LF
    StringUtils::replace_no_expand(manifest, "\r\n", "\n");

    // (2) remove all new-line continuation (remove all "\n " substrings)
    StringUtils::replace_no_expand(manifest, "\n ", "");
  }

  *manifest_size = (jint)strlen(manifest);
  return manifest;
}

char* ClassLoaderExt::get_class_path_attr(const char* jar_path, char* manifest, jint manifest_size) {
  const char* tag = "Class-Path: ";
  const int tag_len = (int)strlen(tag);
  char* found = nullptr;
  char* line_start = manifest;
  char* end = manifest + manifest_size;

  assert(*end == 0, "must be nul-terminated");

  while (line_start < end) {
    char* line_end = strchr(line_start, '\n');
    if (line_end == nullptr) {
      // JAR spec require the manifest file to be terminated by a new line.
      break;
    }
    if (strncmp(tag, line_start, tag_len) == 0) {
      if (found != nullptr) {
        // Same behavior as jdk/src/share/classes/java/util/jar/Attributes.java
        // If duplicated entries are found, the last one is used.
        log_warning(cds)("Warning: Duplicate name in Manifest: %s.\n"
                      "Ensure that the manifest does not have duplicate entries, and\n"
                      "that blank lines separate individual sections in both your\n"
                      "manifest and in the META-INF/MANIFEST.MF entry in the jar file:\n%s\n", tag, jar_path);
      }
      found = line_start + tag_len;
      assert(found <= line_end, "sanity");
      *line_end = '\0';
    }
    line_start = line_end + 1;
  }
  return found;
}

void ClassLoaderExt::process_jar_manifest(JavaThread* current, ClassPathEntry* entry) {
  ResourceMark rm(current);
  jint manifest_size;
  char* manifest = read_manifest(current, entry, &manifest_size);

  if (manifest == nullptr) {
    return;
  }

  if (strstr(manifest, "Extension-List:") != nullptr) {
    vm_exit_during_cds_dumping(err_msg("-Xshare:dump does not support Extension-List in JAR manifest: %s", entry->name()));
  }

  char* cp_attr = get_class_path_attr(entry->name(), manifest, manifest_size);

  if (cp_attr != nullptr && strlen(cp_attr) > 0) {
    trace_class_path("found Class-Path: ", cp_attr);

    char sep = os::file_separator()[0];
    const char* dir_name = entry->name();
    const char* dir_tail = strrchr(dir_name, sep);
    int dir_len;
    if (dir_tail == nullptr) {
      dir_len = 0;
    } else {
      dir_len = dir_tail - dir_name + 1;
    }

    // Split the cp_attr by spaces, and add each file
    char* file_start = cp_attr;
    char* end = file_start + strlen(file_start);

    while (file_start < end) {
      char* file_end = strchr(file_start, ' ');
      if (file_end != nullptr) {
        *file_end = 0;
        file_end += 1;
      } else {
        file_end = end;
      }

      size_t name_len = strlen(file_start);
      if (name_len > 0) {
        ResourceMark rm(current);
        size_t libname_len = dir_len + name_len;
        char* libname = NEW_RESOURCE_ARRAY(char, libname_len + 1);
        int n = os::snprintf(libname, libname_len + 1, "%.*s%s", dir_len, dir_name, file_start);
        assert((size_t)n == libname_len, "Unexpected number of characters in string");
        if (ClassLoader::update_class_path_entry_list(current, libname, true, false, true /* from_class_path_attr */)) {
          trace_class_path("library = ", libname);
        } else {
          trace_class_path("library (non-existent) = ", libname);
          FileMapInfo::record_non_existent_class_path_entry(libname);
        }
      }

      file_start = file_end;
    }
  }
}

void ClassLoaderExt::setup_search_paths(JavaThread* current) {
  ClassLoaderExt::setup_app_search_path(current);
}

void ClassLoaderExt::record_result(const s2 classpath_index, InstanceKlass* result, bool redefined) {
  Arguments::assert_is_dumping_archive();

  // We need to remember where the class comes from during dumping.
  oop loader = result->class_loader();
  s2 classloader_type = ClassLoader::BOOT_LOADER;
  if (SystemDictionary::is_system_class_loader(loader)) {
    classloader_type = ClassLoader::APP_LOADER;
    ClassLoaderExt::set_has_app_classes();
  } else if (SystemDictionary::is_platform_class_loader(loader)) {
    classloader_type = ClassLoader::PLATFORM_LOADER;
    ClassLoaderExt::set_has_platform_classes();
  }
  if (classpath_index > ClassLoaderExt::max_used_path_index()) {
    ClassLoaderExt::set_max_used_path_index(classpath_index);
  }
  result->set_shared_classpath_index(classpath_index);
  result->set_shared_class_loader_type(classloader_type);
#if INCLUDE_CDS_JAVA_HEAP
  if (DumpSharedSpaces && AllowArchivingWithJavaAgent && classloader_type == ClassLoader::BOOT_LOADER &&
      classpath_index < 0 && HeapShared::can_write() && redefined) {
    // During static dump, classes for the built-in loaders are always loaded from
    // known locations (jimage, classpath or modulepath), so classpath_index should
    // always be >= 0.
    // The only exception is when a java agent is used during dump time (for testing
    // purposes only). If a class is transformed by the agent, the CodeSource of
    // this class may point to an unknown location. This may break heap object archiving,
    // which requires all the boot classes to be from known locations. This is an
    // uncommon scenario (even in test cases). Let's simply disable heap object archiving.
    ResourceMark rm;
    log_warning(cds)("CDS heap objects cannot be written because class %s maybe modified by ClassFileLoadHook.",
                     result->external_name());
    HeapShared::disable_writing();
  }
#endif // INCLUDE_CDS_JAVA_HEAP
}