/*

 * Copyright (c) 1997, 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

 * questions.

 *

 */

#include "precompiled.hpp"

#include "classfile/classLoader.hpp"

#include "classfile/javaClasses.hpp"

#include "classfile/systemDictionary.hpp"

#include "classfile/vmSymbols.hpp"

#include "code/codeCache.hpp"

#include "code/icBuffer.hpp"

#include "code/vtableStubs.hpp"

#include "gc/shared/vmGCOperations.hpp"

#include "interpreter/interpreter.hpp"

#include "logging/log.hpp"

#include "memory/allocation.inline.hpp"

#ifdef ASSERT

#include "memory/guardedMemory.hpp"

#endif

#include "oops/oop.inline.hpp"

#include "prims/jvm.h"

#include "prims/jvm_misc.hpp"

#include "prims/privilegedStack.hpp"

#include "runtime/arguments.hpp"

#include "runtime/atomic.inline.hpp"

#include "runtime/frame.inline.hpp"

#include "runtime/interfaceSupport.hpp"

#include "runtime/java.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/os.inline.hpp"

#include "runtime/stubRoutines.hpp"

#include "runtime/thread.inline.hpp"

#include "runtime/vm_version.hpp"

#include "services/attachListener.hpp"

#include "services/mallocTracker.hpp"

#include "services/memTracker.hpp"

#include "services/nmtCommon.hpp"

#include "services/threadService.hpp"

#include "utilities/defaultStream.hpp"

#include "utilities/events.hpp"

# include <signal.h>

OSThread*         os::_starting_thread    = NULL;

address           os::_polling_page       = NULL;

volatile int32_t* os::_mem_serialize_page = NULL;

uintptr_t         os::_serialize_page_mask = 0;

long              os::_rand_seed          = 1;

int               os::_processor_count    = 0;

size_t            os::_page_sizes[os::page_sizes_max];

#ifndef PRODUCT

julong os::num_mallocs = 0;         // # of calls to malloc/realloc

julong os::alloc_bytes = 0;         // # of bytes allocated

julong os::num_frees = 0;           // # of calls to free

julong os::free_bytes = 0;          // # of bytes freed

#endif

static juint cur_malloc_words = 0;  // current size for MallocMaxTestWords

void os_init_globals() {

  // Called from init_globals().

  // See Threads::create_vm() in thread.cpp, and init.cpp.

  os::init_globals();

}

// Fill in buffer with current local time as an ISO-8601 string.

// E.g., yyyy-mm-ddThh:mm:ss-zzzz.

// Returns buffer, or NULL if it failed.

// This would mostly be a call to

//     strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)

// except that on Windows the %z behaves badly, so we do it ourselves.

// Also, people wanted milliseconds on there,

// and strftime doesn't do milliseconds.

char* os::iso8601_time(char* buffer, size_t buffer_length) {

  // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"

  //                                      1         2

  //                             12345678901234567890123456789

  // format string: "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d"

  static const size_t needed_buffer = 29;

  // Sanity check the arguments

  if (buffer == NULL) {

    assert(false, "NULL buffer");

    return NULL;

  }

  if (buffer_length < needed_buffer) {

    assert(false, "buffer_length too small");

    return NULL;

  }

  // Get the current time

  jlong milliseconds_since_19700101 = javaTimeMillis();

  const int milliseconds_per_microsecond = 1000;

  const time_t seconds_since_19700101 =

    milliseconds_since_19700101 / milliseconds_per_microsecond;

  const int milliseconds_after_second =

    milliseconds_since_19700101 % milliseconds_per_microsecond;

  // Convert the time value to a tm and timezone variable

  struct tm time_struct;

  if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {

    assert(false, "Failed localtime_pd");

    return NULL;

  }

#if defined(_ALLBSD_SOURCE)

  const time_t zone = (time_t) time_struct.tm_gmtoff;

#else

  const time_t zone = timezone;

#endif

  // If daylight savings time is in effect,

  // we are 1 hour East of our time zone

  const time_t seconds_per_minute = 60;

  const time_t minutes_per_hour = 60;

  const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;

  time_t UTC_to_local = zone;

  if (time_struct.tm_isdst > 0) {

    UTC_to_local = UTC_to_local - seconds_per_hour;

  }

  // Compute the time zone offset.

  //    localtime_pd() sets timezone to the difference (in seconds)

  //    between UTC and and local time.

  //    ISO 8601 says we need the difference between local time and UTC,

  //    we change the sign of the localtime_pd() result.

  const time_t local_to_UTC = -(UTC_to_local);

  // Then we have to figure out if if we are ahead (+) or behind (-) UTC.

  char sign_local_to_UTC = '+';

  time_t abs_local_to_UTC = local_to_UTC;

  if (local_to_UTC < 0) {

    sign_local_to_UTC = '-';

    abs_local_to_UTC = -(abs_local_to_UTC);

  }

  // Convert time zone offset seconds to hours and minutes.

  const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);

  const time_t zone_min =

    ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);

  // Print an ISO 8601 date and time stamp into the buffer

  const int year = 1900 + time_struct.tm_year;

  const int month = 1 + time_struct.tm_mon;

  const int printed = jio_snprintf(buffer, buffer_length,

                                   "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d",

                                   year,

                                   month,

                                   time_struct.tm_mday,

                                   time_struct.tm_hour,

                                   time_struct.tm_min,

                                   time_struct.tm_sec,

                                   milliseconds_after_second,

                                   sign_local_to_UTC,

                                   zone_hours,

                                   zone_min);

  if (printed == 0) {

    assert(false, "Failed jio_printf");

    return NULL;

  }

  return buffer;

}

OSReturn os::set_priority(Thread* thread, ThreadPriority p) {

#ifdef ASSERT

  if (!(!thread->is_Java_thread() ||

         Thread::current() == thread  ||

         Threads_lock->owned_by_self()

         || thread->is_Compiler_thread()

        )) {

    assert(false, "possibility of dangling Thread pointer");

  }

#endif

  if (p >= MinPriority && p <= MaxPriority) {

    int priority = java_to_os_priority[p];

    return set_native_priority(thread, priority);

  } else {

    assert(false, "Should not happen");

    return OS_ERR;

  }

}

// The mapping from OS priority back to Java priority may be inexact because

// Java priorities can map M:1 with native priorities. If you want the definite

// Java priority then use JavaThread::java_priority()

OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {

  int p;

  int os_prio;

  OSReturn ret = get_native_priority(thread, &os_prio);

  if (ret != OS_OK) return ret;

  if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {

    for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;

  } else {

    // niceness values are in reverse order

    for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ;

  }

  priority = (ThreadPriority)p;

  return OS_OK;

}

// --------------------- sun.misc.Signal (optional) ---------------------

// SIGBREAK is sent by the keyboard to query the VM state

#ifndef SIGBREAK

#define SIGBREAK SIGQUIT

#endif

// sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.

static void signal_thread_entry(JavaThread* thread, TRAPS) {

  os::set_priority(thread, NearMaxPriority);

  while (true) {

    int sig;

    {

      // FIXME : Currently we have not decided what should be the status

      //         for this java thread blocked here. Once we decide about

      //         that we should fix this.

      sig = os::signal_wait();

    }

    if (sig == os::sigexitnum_pd()) {

       // Terminate the signal thread

       return;

    }

    switch (sig) {

      case SIGBREAK: {

        // Check if the signal is a trigger to start the Attach Listener - in that

        // case don't print stack traces.

        if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {

          continue;

        }

        // Print stack traces

        // Any SIGBREAK operations added here should make sure to flush

        // the output stream (e.g. tty->flush()) after output.  See 4803766.

        // Each module also prints an extra carriage return after its output.

        VM_PrintThreads op;

        VMThread::execute(&op);

        VM_PrintJNI jni_op;

        VMThread::execute(&jni_op);

        VM_FindDeadlocks op1(tty);

        VMThread::execute(&op1);

        Universe::print_heap_at_SIGBREAK();

        if (PrintClassHistogram) {

          VM_GC_HeapInspection op1(tty, true /* force full GC before heap inspection */);

          VMThread::execute(&op1);

        }

        if (JvmtiExport::should_post_data_dump()) {

          JvmtiExport::post_data_dump();

        }

        break;

      }

      default: {

        // Dispatch the signal to java

        HandleMark hm(THREAD);

        Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_Signal(), THREAD);

        KlassHandle klass (THREAD, k);

        if (klass.not_null()) {

          JavaValue result(T_VOID);

          JavaCallArguments args;

          args.push_int(sig);

          JavaCalls::call_static(

            &result,

            klass,

            vmSymbols::dispatch_name(),

            vmSymbols::int_void_signature(),

            &args,

            THREAD

          );

        }

        if (HAS_PENDING_EXCEPTION) {

          // tty is initialized early so we don't expect it to be null, but

          // if it is we can't risk doing an initialization that might

          // trigger additional out-of-memory conditions

          if (tty != NULL) {

            char klass_name[256];

            char tmp_sig_name[16];

            const char* sig_name = "UNKNOWN";

            InstanceKlass::cast(PENDING_EXCEPTION->klass())->

              name()->as_klass_external_name(klass_name, 256);

            if (os::exception_name(sig, tmp_sig_name, 16) != NULL)

              sig_name = tmp_sig_name;

            warning("Exception %s occurred dispatching signal %s to handler"

                    "- the VM may need to be forcibly terminated",

                    klass_name, sig_name );

          }

          CLEAR_PENDING_EXCEPTION;

        }

      }

    }

  }

}

void os::init_before_ergo() {

  // We need to initialize large page support here because ergonomics takes some

  // decisions depending on large page support and the calculated large page size.

  large_page_init();

  // VM version initialization identifies some characteristics of the

  VM_Version::init_before_ergo();

}

void os::signal_init() {

  if (!ReduceSignalUsage) {

    // Setup JavaThread for processing signals

    EXCEPTION_MARK;

    Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);

    instanceKlassHandle klass (THREAD, k);

    instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);

    const char thread_name[] = "Signal Dispatcher";

    Handle string = java_lang_String::create_from_str(thread_name, CHECK);

    // Initialize thread_oop to put it into the system threadGroup

    Handle thread_group (THREAD, Universe::system_thread_group());

    JavaValue result(T_VOID);

    JavaCalls::call_special(&result, thread_oop,

                           klass,

                           vmSymbols::object_initializer_name(),

                           vmSymbols::threadgroup_string_void_signature(),

                           thread_group,

                           string,

                           CHECK);

    KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());

    JavaCalls::call_special(&result,

                            thread_group,

                            group,

                            vmSymbols::add_method_name(),

                            vmSymbols::thread_void_signature(),

                            thread_oop,         // ARG 1

                            CHECK);

    os::signal_init_pd();

    { MutexLocker mu(Threads_lock);

      JavaThread* signal_thread = new JavaThread(&signal_thread_entry);

      // At this point it may be possible that no osthread was created for the

      // JavaThread due to lack of memory. We would have to throw an exception

      // in that case. However, since this must work and we do not allow

      // exceptions anyway, check and abort if this fails.

      if (signal_thread == NULL || signal_thread->osthread() == NULL) {

        vm_exit_during_initialization("java.lang.OutOfMemoryError",

                                      os::native_thread_creation_failed_msg());

      }

      java_lang_Thread::set_thread(thread_oop(), signal_thread);

      java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);

      java_lang_Thread::set_daemon(thread_oop());

      signal_thread->set_threadObj(thread_oop());

      Threads::add(signal_thread);

      Thread::start(signal_thread);

    }

    // Handle ^BREAK

    os::signal(SIGBREAK, os::user_handler());

  }

}

void os::terminate_signal_thread() {

  if (!ReduceSignalUsage)

    signal_notify(sigexitnum_pd());

}

// --------------------- loading libraries ---------------------

typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);

extern struct JavaVM_ main_vm;

static void* _native_java_library = NULL;

void* os::native_java_library() {

  if (_native_java_library == NULL) {

    char buffer[JVM_MAXPATHLEN];

    char ebuf[1024];

    // Try to load verify dll first. In 1.3 java dll depends on it and is not

    // always able to find it when the loading executable is outside the JDK.

    // In order to keep working with 1.2 we ignore any loading errors.

    if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),

                       "verify")) {

      dll_load(buffer, ebuf, sizeof(ebuf));

    }

    // Load java dll

    if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),

                       "java")) {

      _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));

    }

    if (_native_java_library == NULL) {

      vm_exit_during_initialization("Unable to load native library", ebuf);

    }

#if defined(__OpenBSD__)

    // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so

    // ignore errors

    if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),

                       "net")) {

      dll_load(buffer, ebuf, sizeof(ebuf));

    }

#endif

  }

  return _native_java_library;

}

/*

 * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists.

 * If check_lib == true then we are looking for an

 * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if

 * this library is statically linked into the image.

 * If check_lib == false then we will look for the appropriate symbol in the

 * executable if agent_lib->is_static_lib() == true or in the shared library

 * referenced by 'handle'.

 */

void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib,

                              const char *syms[], size_t syms_len) {

  assert(agent_lib != NULL, "sanity check");

  const char *lib_name;

  void *handle = agent_lib->os_lib();

  void *entryName = NULL;

  char *agent_function_name;

  size_t i;

  // If checking then use the agent name otherwise test is_static_lib() to

  // see how to process this lookup

  lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL);

  for (i = 0; i < syms_len; i++) {

    agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path());

    if (agent_function_name == NULL) {

      break;

    }

    entryName = dll_lookup(handle, agent_function_name);

    FREE_C_HEAP_ARRAY(char, agent_function_name);

    if (entryName != NULL) {

      break;

    }

  }

  return entryName;

}

// See if the passed in agent is statically linked into the VM image.

bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],

                            size_t syms_len) {

  void *ret;

  void *proc_handle;

  void *save_handle;

  assert(agent_lib != NULL, "sanity check");

  if (agent_lib->name() == NULL) {

    return false;

  }

  proc_handle = get_default_process_handle();

  // Check for Agent_OnLoad/Attach_lib_name function

  save_handle = agent_lib->os_lib();

  // We want to look in this process' symbol table.

  agent_lib->set_os_lib(proc_handle);

  ret = find_agent_function(agent_lib, true, syms, syms_len);

  if (ret != NULL) {

    // Found an entry point like Agent_OnLoad_lib_name so we have a static agent

    agent_lib->set_valid();

    agent_lib->set_static_lib(true);

    return true;

  }

  agent_lib->set_os_lib(save_handle);

  return false;

}

// --------------------- heap allocation utilities ---------------------

char *os::strdup(const char *str, MEMFLAGS flags) {

  size_t size = strlen(str);

  char *dup_str = (char *)malloc(size + 1, flags);

  if (dup_str == NULL) return NULL;

  strcpy(dup_str, str);

  return dup_str;

}