/*

 * Copyright (c) 1997, 2019, 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/javaClasses.hpp"

#include "classfile/symbolTable.hpp"

#include "classfile/systemDictionary.hpp"

#include "classfile/vmSymbols.hpp"

#include "logging/log.hpp"

#include "logging/logTag.hpp"

#include "memory/oopFactory.hpp"

#include "memory/resourceArea.hpp"

#include "oops/instanceKlass.hpp"

#include "oops/method.hpp"

#include "oops/oop.inline.hpp"

#include "oops/symbol.hpp"

#include "prims/jvm_misc.hpp"

#include "prims/nativeLookup.hpp"

#include "prims/unsafe.hpp"

#include "runtime/arguments.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/interfaceSupport.inline.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/os.inline.hpp"

#include "runtime/sharedRuntime.hpp"

#include "runtime/signature.hpp"

#include "utilities/macros.hpp"

#include "utilities/utf8.hpp"

#if INCLUDE_JFR

#include "jfr/jfr.hpp"

#endif

static void mangle_name_on(outputStream* st, Symbol* name, int begin, int end) {

  char* bytes = (char*)name->bytes() + begin;

  char* end_bytes = (char*)name->bytes() + end;

  while (bytes < end_bytes) {

    jchar c;

    bytes = UTF8::next(bytes, &c);

    if (c <= 0x7f && isalnum(c)) {

      st->put((char) c);

    } else {

           if (c == '_') st->print("_1");

      else if (c == '/') st->print("_");

      else if (c == ';') st->print("_2");

      else if (c == '[') st->print("_3");

      else               st->print("_%.5x", c);

    }

  }

}

static void mangle_name_on(outputStream* st, Symbol* name) {

  mangle_name_on(st, name, 0, name->utf8_length());

}

char* NativeLookup::pure_jni_name(const methodHandle& method) {

  stringStream st;

  // Prefix

  st.print("Java_");

  // Klass name

  mangle_name_on(&st, method->klass_name());

  st.print("_");

  // Method name

  mangle_name_on(&st, method->name());

  return st.as_string();

}

char* NativeLookup::critical_jni_name(const methodHandle& method) {

  stringStream st;

  // Prefix

  st.print("JavaCritical_");

  // Klass name

  mangle_name_on(&st, method->klass_name());

  st.print("_");

  // Method name

  mangle_name_on(&st, method->name());

  return st.as_string();

}

char* NativeLookup::long_jni_name(const methodHandle& method) {

  // Signature ignore the wrapping parenteses and the trailing return type

  stringStream st;

  Symbol* signature = method->signature();

  st.print("__");

  // find ')'

  int end;

  for (end = 0; end < signature->utf8_length() && signature->char_at(end) != JVM_SIGNATURE_ENDFUNC; end++);

  // skip first '('

  mangle_name_on(&st, signature, 1, end);

  return st.as_string();

}

extern "C" {

  void JNICALL JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass unsafecls);

  void JNICALL JVM_RegisterPerfMethods(JNIEnv *env, jclass perfclass);

  void JNICALL JVM_RegisterWhiteBoxMethods(JNIEnv *env, jclass wbclass);

#if INCLUDE_JVMCI

  jobject  JNICALL JVM_GetJVMCIRuntime(JNIEnv *env, jclass c);

  void     JNICALL JVM_RegisterJVMCINatives(JNIEnv *env, jclass compilerToVMClass);

#endif

}

#define CC (char*)  /* cast a literal from (const char*) */

#define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)

static JNINativeMethod lookup_special_native_methods[] = {

  { CC"Java_jdk_internal_misc_Unsafe_registerNatives",             NULL, FN_PTR(JVM_RegisterJDKInternalMiscUnsafeMethods) },

  { CC"Java_java_lang_invoke_MethodHandleNatives_registerNatives", NULL, FN_PTR(JVM_RegisterMethodHandleMethods) },

  { CC"Java_jdk_internal_perf_Perf_registerNatives",               NULL, FN_PTR(JVM_RegisterPerfMethods)         },

  { CC"Java_sun_hotspot_WhiteBox_registerNatives",                 NULL, FN_PTR(JVM_RegisterWhiteBoxMethods)     },

#if INCLUDE_JVMCI

  { CC"Java_jdk_vm_ci_runtime_JVMCI_initializeRuntime",            NULL, FN_PTR(JVM_GetJVMCIRuntime)             },

  { CC"Java_jdk_vm_ci_hotspot_CompilerToVM_registerNatives",       NULL, FN_PTR(JVM_RegisterJVMCINatives)        },

#endif

#if INCLUDE_JFR

  { CC"Java_jdk_jfr_internal_JVM_registerNatives",                 NULL, FN_PTR(jfr_register_natives)            },

#endif

};

static address lookup_special_native(const char* jni_name) {

  int count = sizeof(lookup_special_native_methods) / sizeof(JNINativeMethod);

  for (int i = 0; i < count; i++) {

    // NB: To ignore the jni prefix and jni postfix strstr is used matching.

    if (strstr(jni_name, lookup_special_native_methods[i].name) != NULL) {

      return CAST_FROM_FN_PTR(address, lookup_special_native_methods[i].fnPtr);

    }

  }

  return NULL;

}

address NativeLookup::lookup_style(const methodHandle& method, char* pure_name, const char* long_name, int args_size, bool os_style, bool& in_base_library, TRAPS) {

  address entry;

  const char* jni_name = compute_complete_jni_name(pure_name, long_name, args_size, os_style);

  // If the loader is null we have a system class, so we attempt a lookup in

  // the native Java library. This takes care of any bootstrapping problems.

  // Note: It is critical for bootstrapping that Java_java_lang_ClassLoader_00024NativeLibrary_find

  // gets found the first time around - otherwise an infinite loop can occure. This is

  // another VM/library dependency

  Handle loader(THREAD, method->method_holder()->class_loader());

  if (loader.is_null()) {

    entry = lookup_special_native(jni_name);

    if (entry == NULL) {

       entry = (address) os::dll_lookup(os::native_java_library(), jni_name);

    }

    if (entry != NULL) {

      in_base_library = true;

      return entry;

    }

  }

  // Otherwise call static method findNative in ClassLoader

  Klass*   klass = SystemDictionary::ClassLoader_klass();

  Handle name_arg = java_lang_String::create_from_str(jni_name, CHECK_NULL);

  JavaValue result(T_LONG);

  JavaCalls::call_static(&result,

                         klass,

                         vmSymbols::findNative_name(),

                         vmSymbols::classloader_string_long_signature(),

                         // Arguments

                         loader,

                         name_arg,

                         CHECK_NULL);

  entry = (address) (intptr_t) result.get_jlong();

  if (entry == NULL) {

    // findNative didn't find it, if there are any agent libraries look in them

    AgentLibrary* agent;

    for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {

      entry = (address) os::dll_lookup(agent->os_lib(), jni_name);

      if (entry != NULL) {

        return entry;

      }

    }

  }

  return entry;

}

const char* NativeLookup::compute_complete_jni_name(const char* pure_name, const char* long_name, int args_size, bool os_style) {

  stringStream st;

  if (os_style) {

    os::print_jni_name_prefix_on(&st, args_size);

  }

  st.print_raw(pure_name);

  st.print_raw(long_name);

  if (os_style) {

    os::print_jni_name_suffix_on(&st, args_size);

  }

  return st.as_string();

}

address NativeLookup::lookup_critical_style(void* dll, const char* pure_name, const char* long_name, int args_size, bool os_style) {

  const char* jni_name = compute_complete_jni_name(pure_name, long_name, args_size, os_style);

  assert(dll != NULL, "dll must be loaded");

  return (address)os::dll_lookup(dll, jni_name);

}

// Check all the formats of native implementation name to see if there is one

// for the specified method.

address NativeLookup::lookup_entry(const methodHandle& method, bool& in_base_library, TRAPS) {

  address entry = NULL;

  in_base_library = false;

  // Compute pure name

  char* pure_name = pure_jni_name(method);

  // Compute argument size

  int args_size = 1                             // JNIEnv

                + (method->is_static() ? 1 : 0) // class for static methods

                + method->size_of_parameters(); // actual parameters

  // 1) Try JNI short style

  entry = lookup_style(method, pure_name, "",        args_size, true,  in_base_library, CHECK_NULL);

  if (entry != NULL) return entry;

  // Compute long name

  char* long_name = long_jni_name(method);

  // 2) Try JNI long style

  entry = lookup_style(method, pure_name, long_name, args_size, true,  in_base_library, CHECK_NULL);

  if (entry != NULL) return entry;

  // 3) Try JNI short style without os prefix/suffix

  entry = lookup_style(method, pure_name, "",        args_size, false, in_base_library, CHECK_NULL);

  if (entry != NULL) return entry;

  // 4) Try JNI long style without os prefix/suffix

  entry = lookup_style(method, pure_name, long_name, args_size, false, in_base_library, CHECK_NULL);

  return entry; // NULL indicates not found

}

// Check all the formats of native implementation name to see if there is one

// for the specified method.

address NativeLookup::lookup_critical_entry(const methodHandle& method) {

  assert(CriticalJNINatives, "or should not be here");

  if (method->is_synchronized() ||

      !method->is_static()) {

    // Only static non-synchronized methods are allowed

    return NULL;

  }

  ResourceMark rm;

  Symbol* signature = method->signature();

  for (int end = 0; end < signature->utf8_length(); end++) {

    if (signature->char_at(end) == 'L') {

      // Don't allow object types

      return NULL;

    }

  }

  // Compute argument size

  int args_size = method->size_of_parameters();

  for (SignatureStream ss(signature); !ss.at_return_type(); ss.next()) {

    if (ss.is_array()) {

      args_size += T_INT_size; // array length parameter

    }

  }

  // dll handling requires I/O. Don't do that while in _thread_in_vm (safepoint may get requested).

  ThreadToNativeFromVM thread_in_native(JavaThread::current());

  void* dll = dll_load(method);

  address entry = NULL;

  if (dll != NULL) {

    entry = lookup_critical_style(dll, method, args_size);

    // Close the handle to avoid keeping the library alive if the native method holder is unloaded.

    // This is fine because the library is still kept alive by JNI (see JVM_LoadLibrary). As soon

    // as the holder class and the library are unloaded (see JVM_UnloadLibrary), the native wrapper

    // that calls 'critical_entry' becomes unreachable and is unloaded as well.

    os::dll_unload(dll);

  }

  return entry; // NULL indicates not found

}

void* NativeLookup::dll_load(const methodHandle& method) {

  if (method->has_native_function()) {

    address current_entry = method->native_function();

    char dll_name[JVM_MAXPATHLEN];

    int offset;

    if (os::dll_address_to_library_name(current_entry, dll_name, sizeof(dll_name), &offset)) {

      char ebuf[32];

      return os::dll_load(dll_name, ebuf, sizeof(ebuf));

    }

  }

  return NULL;

}

address NativeLookup::lookup_critical_style(void* dll, const methodHandle& method, int args_size) {

  address entry = NULL;

  const char* critical_name = critical_jni_name(method);

  // 1) Try JNI short style

  entry = lookup_critical_style(dll, critical_name, "",        args_size, true);

  if (entry != NULL) {

    return entry;

  }

  const char* long_name = long_jni_name(method);

  // 2) Try JNI long style

  entry = lookup_critical_style(dll, critical_name, long_name, args_size, true);

  if (entry != NULL) {

    return entry;

  }

  // 3) Try JNI short style without os prefix/suffix

  entry = lookup_critical_style(dll, critical_name, "",        args_size, false);

  if (entry != NULL) {

    return entry;

  }

  // 4) Try JNI long style without os prefix/suffix

  return lookup_critical_style(dll, critical_name, long_name, args_size, false);

}

// Check if there are any JVM TI prefixes which have been applied to the native method name.

// If any are found, remove them before attemping the look up of the

// native implementation again.

// See SetNativeMethodPrefix in the JVM TI Spec for more details.

address NativeLookup::lookup_entry_prefixed(const methodHandle& method, bool& in_base_library, TRAPS) {

#if INCLUDE_JVMTI

  ResourceMark rm(THREAD);

  int prefix_count;

  char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);

  char* in_name = method->name()->as_C_string();

  char* wrapper_name = in_name;

  // last applied prefix will be first -- go backwards

  for (int i = prefix_count-1; i >= 0; i--) {

    char* prefix = prefixes[i];

    size_t prefix_len = strlen(prefix);

    if (strncmp(prefix, wrapper_name, prefix_len) == 0) {

      // has this prefix remove it

      wrapper_name += prefix_len;

    }

  }

  if (wrapper_name != in_name) {

    // we have a name for a wrapping method

    int wrapper_name_len = (int)strlen(wrapper_name);

    TempNewSymbol wrapper_symbol = SymbolTable::probe(wrapper_name, wrapper_name_len);

    if (wrapper_symbol != NULL) {

      Klass* k = method->method_holder();

      Method* wrapper_method = k->lookup_method(wrapper_symbol, method->signature());

      if (wrapper_method != NULL && !wrapper_method->is_native()) {

        // we found a wrapper method, use its native entry

        method->set_is_prefixed_native();

      }

    }

  }

#endif // INCLUDE_JVMTI

  return NULL;

}

address NativeLookup::lookup_base(const methodHandle& method, bool& in_base_library, TRAPS) {

  address entry = NULL;

  ResourceMark rm(THREAD);

  entry = lookup_entry(method, in_base_library, THREAD);

  if (entry != NULL) return entry;

  // standard native method resolution has failed.  Check if there are any

  // JVM TI prefixes which have been applied to the native method name.

  entry = lookup_entry_prefixed(method, in_base_library, THREAD);

  if (entry != NULL) return entry;

  // Native function not found, throw UnsatisfiedLinkError

  stringStream ss;

  ss.print("'");

  method->print_external_name(&ss);

  ss.print("'");

  THROW_MSG_0(vmSymbols::java_lang_UnsatisfiedLinkError(), ss.as_string());

}

address NativeLookup::lookup(const methodHandle& method, bool& in_base_library, TRAPS) {

  if (!method->has_native_function()) {

    address entry = lookup_base(method, in_base_library, CHECK_NULL);

    method->set_native_function(entry,

      Method::native_bind_event_is_interesting);

    // -verbose:jni printing

    if (log_is_enabled(Debug, jni, resolve)) {

      ResourceMark rm(THREAD);

      log_debug(jni, resolve)("[Dynamic-linking native method %s.%s ... JNI]",

                              method->method_holder()->external_name(),

                              method->name()->as_C_string());

    }

  }

  return method->native_function();

}

address NativeLookup::base_library_lookup(const char* class_name, const char* method_name, const char* signature) {

  EXCEPTION_MARK;

  bool in_base_library = true;  // SharedRuntime inits some math methods.

  TempNewSymbol c_name = SymbolTable::new_symbol(class_name);

  TempNewSymbol m_name = SymbolTable::new_symbol(method_name);

  TempNewSymbol s_name = SymbolTable::new_symbol(signature);

  // Find the class

  Klass* k = SystemDictionary::resolve_or_fail(c_name, true, CATCH);

  InstanceKlass* klass  = InstanceKlass::cast(k);

  // Find method and invoke standard lookup

  methodHandle method (THREAD,

                       klass->uncached_lookup_method(m_name, s_name, Klass::find_overpass));

  address result = lookup(method, in_base_library, CATCH);

  assert(in_base_library, "must be in basic library");

  guarantee(result != NULL, "must be non NULL");

  return result;

}