1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_CLASSFILE_CLASSLOADER_HPP
  26 #define SHARE_VM_CLASSFILE_CLASSLOADER_HPP
  27 
  28 #include "classfile/classFileParser.hpp"
  29 #include "runtime/perfData.hpp"
  30 
  31 // The VM class loader.
  32 #include <sys/stat.h>
  33 
  34 
  35 // Meta-index (optional, to be able to skip opening boot classpath jar files)
  36 class MetaIndex: public CHeapObj<mtClass> {
  37  private:
  38   char** _meta_package_names;
  39   int    _num_meta_package_names;
  40  public:
  41   MetaIndex(char** meta_package_names, int num_meta_package_names);
  42   ~MetaIndex();
  43   bool may_contain(const char* class_name);
  44 };
  45 
  46 
  47 // Class path entry (directory or zip file)
  48 
  49 class ClassPathEntry: public CHeapObj<mtClass> {
  50  private:
  51   ClassPathEntry* _next;
  52  public:
  53   // Next entry in class path
  54   ClassPathEntry* next()              { return _next; }
  55   void set_next(ClassPathEntry* next) {
  56     // may have unlocked readers, so write atomically.
  57     OrderAccess::release_store_ptr(&_next, next);
  58   }
  59   virtual bool is_jar_file() = 0;
  60   virtual const char* name() = 0;
  61   virtual bool is_lazy();
  62   // Constructor
  63   ClassPathEntry();
  64   // Attempt to locate file_name through this class path entry.
  65   // Returns a class file parsing stream if successfull.
  66   virtual ClassFileStream* open_stream(const char* name, TRAPS) = 0;
  67   // Debugging
  68   NOT_PRODUCT(virtual void compile_the_world(Handle loader, TRAPS) = 0;)
  69   NOT_PRODUCT(virtual bool is_rt_jar() = 0;)
  70 };
  71 
  72 
  73 class ClassPathDirEntry: public ClassPathEntry {
  74  private:
  75   const char* _dir;           // Name of directory
  76  public:
  77   bool is_jar_file()  { return false;  }
  78   const char* name()  { return _dir; }
  79   ClassPathDirEntry(const char* dir);
  80   ClassFileStream* open_stream(const char* name, TRAPS);
  81   // Debugging
  82   NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
  83   NOT_PRODUCT(bool is_rt_jar();)
  84 };
  85 
  86 
  87 // Type definitions for zip file and zip file entry
  88 typedef void* jzfile;
  89 typedef struct {
  90   char *name;                   /* entry name */
  91   jlong time;                   /* modification time */
  92   jlong size;                   /* size of uncompressed data */
  93   jlong csize;                  /* size of compressed data (zero if uncompressed) */
  94   jint crc;                     /* crc of uncompressed data */
  95   char *comment;                /* optional zip file comment */
  96   jbyte *extra;                 /* optional extra data */
  97   jlong pos;                    /* position of LOC header (if negative) or data */
  98 } jzentry;
  99 
 100 
 101 class ClassPathZipEntry: public ClassPathEntry {
 102  private:
 103   jzfile* _zip;              // The zip archive
 104   const char*   _zip_name;   // Name of zip archive
 105  public:
 106   bool is_jar_file()  { return true;  }
 107   const char* name()  { return _zip_name; }
 108   ClassPathZipEntry(jzfile* zip, const char* zip_name);
 109   ~ClassPathZipEntry();
 110   u1* open_entry(const char* name, jint* filesize, bool nul_terminate, TRAPS);
 111   ClassFileStream* open_stream(const char* name, TRAPS);
 112   void contents_do(void f(const char* name, void* context), void* context);
 113   // Debugging
 114   NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
 115   NOT_PRODUCT(void compile_the_world12(Handle loader, TRAPS);) // JDK 1.2 version
 116   NOT_PRODUCT(void compile_the_world13(Handle loader, TRAPS);) // JDK 1.3 version
 117   NOT_PRODUCT(bool is_rt_jar();)
 118   NOT_PRODUCT(bool is_rt_jar12();)
 119   NOT_PRODUCT(bool is_rt_jar13();)
 120 };
 121 
 122 
 123 // For lazier loading of boot class path entries
 124 class LazyClassPathEntry: public ClassPathEntry {
 125  private:
 126   const char* _path; // dir or file
 127   struct stat _st;
 128   MetaIndex* _meta_index;
 129   bool _has_error;
 130   bool _throw_exception;
 131   volatile ClassPathEntry* _resolved_entry;
 132  public:
 133   ClassPathEntry* resolve_entry(TRAPS);
 134   bool is_jar_file();
 135   const char* name()  { return _path; }
 136   LazyClassPathEntry(const char* path, const struct stat* st, bool throw_exception);
 137   u1* open_entry(const char* name, jint* filesize, bool nul_terminate, TRAPS);
 138   ClassFileStream* open_stream(const char* name, TRAPS);
 139   void set_meta_index(MetaIndex* meta_index) { _meta_index = meta_index; }
 140   virtual bool is_lazy();
 141   // Debugging
 142   NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)
 143   NOT_PRODUCT(bool is_rt_jar();)
 144 };
 145 
 146 class PackageHashtable;
 147 class PackageInfo;
 148 class SharedPathsMiscInfo;
 149 template <MEMFLAGS F> class HashtableBucket;
 150 
 151 class ClassLoader: AllStatic {
 152  public:
 153   enum SomeConstants {
 154     package_hash_table_size = 31  // Number of buckets
 155   };
 156  protected:
 157   friend class LazyClassPathEntry;
 158 
 159   // Performance counters
 160   static PerfCounter* _perf_accumulated_time;
 161   static PerfCounter* _perf_classes_inited;
 162   static PerfCounter* _perf_class_init_time;
 163   static PerfCounter* _perf_class_init_selftime;
 164   static PerfCounter* _perf_classes_verified;
 165   static PerfCounter* _perf_class_verify_time;
 166   static PerfCounter* _perf_class_verify_selftime;
 167   static PerfCounter* _perf_classes_linked;
 168   static PerfCounter* _perf_class_link_time;
 169   static PerfCounter* _perf_class_link_selftime;
 170   static PerfCounter* _perf_class_parse_time;
 171   static PerfCounter* _perf_class_parse_selftime;
 172   static PerfCounter* _perf_sys_class_lookup_time;
 173   static PerfCounter* _perf_shared_classload_time;
 174   static PerfCounter* _perf_sys_classload_time;
 175   static PerfCounter* _perf_app_classload_time;
 176   static PerfCounter* _perf_app_classload_selftime;
 177   static PerfCounter* _perf_app_classload_count;
 178   static PerfCounter* _perf_define_appclasses;
 179   static PerfCounter* _perf_define_appclass_time;
 180   static PerfCounter* _perf_define_appclass_selftime;
 181   static PerfCounter* _perf_app_classfile_bytes_read;
 182   static PerfCounter* _perf_sys_classfile_bytes_read;
 183 
 184   static PerfCounter* _sync_systemLoaderLockContentionRate;
 185   static PerfCounter* _sync_nonSystemLoaderLockContentionRate;
 186   static PerfCounter* _sync_JVMFindLoadedClassLockFreeCounter;
 187   static PerfCounter* _sync_JVMDefineClassLockFreeCounter;
 188   static PerfCounter* _sync_JNIDefineClassLockFreeCounter;
 189 
 190   static PerfCounter* _unsafe_defineClassCallCounter;
 191   static PerfCounter* _isUnsyncloadClass;
 192   static PerfCounter* _load_instance_class_failCounter;
 193 
 194   // First entry in linked list of ClassPathEntry instances
 195   static ClassPathEntry* _first_entry;
 196   // Last entry in linked list of ClassPathEntry instances
 197   static ClassPathEntry* _last_entry;
 198   static int _num_entries;
 199 
 200   // Hash table used to keep track of loaded packages
 201   static PackageHashtable* _package_hash_table;
 202   static const char* _shared_archive;
 203 
 204   // Info used by CDS
 205   CDS_ONLY(static SharedPathsMiscInfo * _shared_paths_misc_info;)
 206 
 207   // Hash function
 208   static unsigned int hash(const char *s, int n);
 209   // Returns the package file name corresponding to the specified package
 210   // or class name, or null if not found.
 211   static PackageInfo* lookup_package(const char *pkgname);
 212   // Adds a new package entry for the specified class or package name and
 213   // corresponding directory or jar file name.
 214   static bool add_package(const char *pkgname, int classpath_index, TRAPS);
 215 
 216   // Initialization
 217   static void setup_bootstrap_meta_index();
 218   static void setup_meta_index(const char* meta_index_path, const char* meta_index_dir,
 219                                int start_index);
 220   static void setup_bootstrap_search_path();
 221   static void setup_search_path(const char *class_path, bool canonicalize=false);
 222 
 223   static void load_zip_library();
 224   static ClassPathEntry* create_class_path_entry(const char *path, const struct stat* st,
 225                                                  bool lazy, bool throw_exception, TRAPS);
 226 
 227   // Canonicalizes path names, so strcmp will work properly. This is mainly
 228   // to avoid confusing the zip library
 229   static bool get_canonical_path(const char* orig, char* out, int len);
 230  public:
 231   static int crc32(int crc, const char* buf, int len);
 232   static bool update_class_path_entry_list(const char *path,
 233                                            bool check_for_duplicates,
 234                                            bool throw_exception=true);
 235   static void print_bootclasspath();
 236 
 237   // Timing
 238   static PerfCounter* perf_accumulated_time()         { return _perf_accumulated_time; }
 239   static PerfCounter* perf_classes_inited()           { return _perf_classes_inited; }
 240   static PerfCounter* perf_class_init_time()          { return _perf_class_init_time; }
 241   static PerfCounter* perf_class_init_selftime()      { return _perf_class_init_selftime; }
 242   static PerfCounter* perf_classes_verified()         { return _perf_classes_verified; }
 243   static PerfCounter* perf_class_verify_time()        { return _perf_class_verify_time; }
 244   static PerfCounter* perf_class_verify_selftime()    { return _perf_class_verify_selftime; }
 245   static PerfCounter* perf_classes_linked()           { return _perf_classes_linked; }
 246   static PerfCounter* perf_class_link_time()          { return _perf_class_link_time; }
 247   static PerfCounter* perf_class_link_selftime()      { return _perf_class_link_selftime; }
 248   static PerfCounter* perf_class_parse_time()         { return _perf_class_parse_time; }
 249   static PerfCounter* perf_class_parse_selftime()     { return _perf_class_parse_selftime; }
 250   static PerfCounter* perf_sys_class_lookup_time()    { return _perf_sys_class_lookup_time; }
 251   static PerfCounter* perf_shared_classload_time()    { return _perf_shared_classload_time; }
 252   static PerfCounter* perf_sys_classload_time()       { return _perf_sys_classload_time; }
 253   static PerfCounter* perf_app_classload_time()       { return _perf_app_classload_time; }
 254   static PerfCounter* perf_app_classload_selftime()   { return _perf_app_classload_selftime; }
 255   static PerfCounter* perf_app_classload_count()      { return _perf_app_classload_count; }
 256   static PerfCounter* perf_define_appclasses()        { return _perf_define_appclasses; }
 257   static PerfCounter* perf_define_appclass_time()     { return _perf_define_appclass_time; }
 258   static PerfCounter* perf_define_appclass_selftime() { return _perf_define_appclass_selftime; }
 259   static PerfCounter* perf_app_classfile_bytes_read() { return _perf_app_classfile_bytes_read; }
 260   static PerfCounter* perf_sys_classfile_bytes_read() { return _perf_sys_classfile_bytes_read; }
 261 
 262   // Record how often system loader lock object is contended
 263   static PerfCounter* sync_systemLoaderLockContentionRate() {
 264     return _sync_systemLoaderLockContentionRate;
 265   }
 266 
 267   // Record how often non system loader lock object is contended
 268   static PerfCounter* sync_nonSystemLoaderLockContentionRate() {
 269     return _sync_nonSystemLoaderLockContentionRate;
 270   }
 271 
 272   // Record how many calls to JVM_FindLoadedClass w/o holding a lock
 273   static PerfCounter* sync_JVMFindLoadedClassLockFreeCounter() {
 274     return _sync_JVMFindLoadedClassLockFreeCounter;
 275   }
 276 
 277   // Record how many calls to JVM_DefineClass w/o holding a lock
 278   static PerfCounter* sync_JVMDefineClassLockFreeCounter() {
 279     return _sync_JVMDefineClassLockFreeCounter;
 280   }
 281 
 282   // Record how many calls to jni_DefineClass w/o holding a lock
 283   static PerfCounter* sync_JNIDefineClassLockFreeCounter() {
 284     return _sync_JNIDefineClassLockFreeCounter;
 285   }
 286 
 287   // Record how many calls to Unsafe_DefineClass
 288   static PerfCounter* unsafe_defineClassCallCounter() {
 289     return _unsafe_defineClassCallCounter;
 290   }
 291 
 292   // Record how many times SystemDictionary::load_instance_class call
 293   // fails with linkageError when Unsyncloadclass flag is set.
 294   static PerfCounter* load_instance_class_failCounter() {
 295     return _load_instance_class_failCounter;
 296   }
 297 
 298   // Load individual .class file
 299   static instanceKlassHandle load_classfile(Symbol* h_name, TRAPS);
 300 
 301   // If the specified package has been loaded by the system, then returns
 302   // the name of the directory or ZIP file that the package was loaded from.
 303   // Returns null if the package was not loaded.
 304   // Note: The specified name can either be the name of a class or package.
 305   // If a package name is specified, then it must be "/"-separator and also
 306   // end with a trailing "/".
 307   static oop get_system_package(const char* name, TRAPS);
 308 
 309   // Returns an array of Java strings representing all of the currently
 310   // loaded system packages.
 311   // Note: The package names returned are "/"-separated and end with a
 312   // trailing "/".
 313   static objArrayOop get_system_packages(TRAPS);
 314 
 315   // Initialization
 316   static void initialize();
 317   CDS_ONLY(static void initialize_shared_path();)
 318   static void create_package_info_table();
 319   static void create_package_info_table(HashtableBucket<mtClass> *t, int length,
 320                                         int number_of_entries);
 321   static int compute_Object_vtable();
 322 
 323   static ClassPathEntry* classpath_entry(int n) {
 324     ClassPathEntry* e = ClassLoader::_first_entry;
 325     while (--n >= 0) {
 326       assert(e != NULL, "Not that many classpath entries.");
 327       e = e->next();
 328     }
 329     return e;
 330   }
 331 
 332   static int num_classpath_entries() {
 333     return _num_entries;
 334   }
 335 
 336 #if INCLUDE_CDS
 337   // Sharing dump and restore
 338   static void copy_package_info_buckets(char** top, char* end);
 339   static void copy_package_info_table(char** top, char* end);
 340 
 341   static void  check_shared_classpath(const char *path);
 342   static void  finalize_shared_paths_misc_info();
 343   static int   get_shared_paths_misc_info_size();
 344   static void* get_shared_paths_misc_info();
 345   static bool  check_shared_paths_misc_info(void* info, int size);
 346   static void  exit_with_path_failure(const char* error, const char* message);
 347 #endif
 348 
 349   static void  trace_class_path(const char* msg, const char* name = NULL);
 350 
 351   // VM monitoring and management support
 352   static jlong classloader_time_ms();
 353   static jlong class_method_total_size();
 354   static jlong class_init_count();
 355   static jlong class_init_time_ms();
 356   static jlong class_verify_time_ms();
 357   static jlong class_link_count();
 358   static jlong class_link_time_ms();
 359 
 360   // indicates if class path already contains a entry (exact match by name)
 361   static bool contains_entry(ClassPathEntry* entry);
 362 
 363   // adds a class path list
 364   static void add_to_list(ClassPathEntry* new_entry);
 365 
 366   // creates a class path zip entry (returns NULL if JAR file cannot be opened)
 367   static ClassPathZipEntry* create_class_path_zip_entry(const char *apath);
 368 
 369   // Debugging
 370   static void verify()              PRODUCT_RETURN;
 371 
 372   // Force compilation of all methods in all classes in bootstrap class path (stress test)
 373 #ifndef PRODUCT
 374  protected:
 375   static int _compile_the_world_class_counter;
 376   static int _compile_the_world_method_counter;
 377  public:
 378   static void compile_the_world();
 379   static void compile_the_world_in(char* name, Handle loader, TRAPS);
 380   static int  compile_the_world_counter() { return _compile_the_world_class_counter; }
 381 #endif //PRODUCT
 382 };
 383 
 384 // PerfClassTraceTime is used to measure time for class loading related events.
 385 // This class tracks cumulative time and exclusive time for specific event types.
 386 // During the execution of one event, other event types (e.g. class loading and
 387 // resolution) as well as recursive calls of the same event type could happen.
 388 // Only one elapsed timer (cumulative) and one thread-local self timer (exclusive)
 389 // (i.e. only one event type) are active at a time even multiple PerfClassTraceTime
 390 // instances have been created as multiple events are happening.
 391 class PerfClassTraceTime {
 392  public:
 393   enum {
 394     CLASS_LOAD   = 0,
 395     PARSE_CLASS  = 1,
 396     CLASS_LINK   = 2,
 397     CLASS_VERIFY = 3,
 398     CLASS_CLINIT = 4,
 399     DEFINE_CLASS = 5,
 400     EVENT_TYPE_COUNT = 6
 401   };
 402  protected:
 403   // _t tracks time from initialization to destruction of this timer instance
 404   // including time for all other event types, and recursive calls of this type.
 405   // When a timer is called recursively, the elapsedTimer _t would not be used.
 406   elapsedTimer     _t;
 407   PerfLongCounter* _timep;
 408   PerfLongCounter* _selftimep;
 409   PerfLongCounter* _eventp;
 410   // pointer to thread-local recursion counter and timer array
 411   // The thread_local timers track cumulative time for specific event types
 412   // exclusive of time for other event types, but including recursive calls
 413   // of the same type.
 414   int*             _recursion_counters;
 415   elapsedTimer*    _timers;
 416   int              _event_type;
 417   int              _prev_active_event;
 418 
 419  public:
 420 
 421   inline PerfClassTraceTime(PerfLongCounter* timep,     /* counter incremented with inclusive time */
 422                             PerfLongCounter* selftimep, /* counter incremented with exclusive time */
 423                             PerfLongCounter* eventp,    /* event counter */
 424                             int* recursion_counters,    /* thread-local recursion counter array */
 425                             elapsedTimer* timers,       /* thread-local timer array */
 426                             int type                    /* event type */ ) :
 427       _timep(timep), _selftimep(selftimep), _eventp(eventp), _recursion_counters(recursion_counters), _timers(timers), _event_type(type) {
 428     initialize();
 429   }
 430 
 431   inline PerfClassTraceTime(PerfLongCounter* timep,     /* counter incremented with inclusive time */
 432                             elapsedTimer* timers,       /* thread-local timer array */
 433                             int type                    /* event type */ ) :
 434       _timep(timep), _selftimep(NULL), _eventp(NULL), _recursion_counters(NULL), _timers(timers), _event_type(type) {
 435     initialize();
 436   }
 437 
 438   inline void suspend() { _t.stop(); _timers[_event_type].stop(); }
 439   inline void resume()  { _t.start(); _timers[_event_type].start(); }
 440 
 441   ~PerfClassTraceTime();
 442   void initialize();
 443 };
 444 
 445 #endif // SHARE_VM_CLASSFILE_CLASSLOADER_HPP