/*

 * Copyright (c) 1997, 2012, 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/icBuffer.hpp"

#include "code/vtableStubs.hpp"

#include "gc_implementation/shared/vmGCOperations.hpp"

#include "interpreter/interpreter.hpp"

#include "memory/allocation.inline.hpp"

#include "oops/oop.inline.hpp"

#include "prims/jvm.h"

#include "prims/jvm_misc.hpp"

#include "prims/privilegedStack.hpp"

#include "runtime/arguments.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.hpp"

#include "runtime/stubRoutines.hpp"

#include "runtime/thread.inline.hpp"

#include "services/attachListener.hpp"

#include "services/memTracker.hpp"

#include "services/threadService.hpp"

#include "utilities/defaultStream.hpp"

#include "utilities/events.hpp"

#ifdef TARGET_OS_FAMILY_linux

# include "os_linux.inline.hpp"

#endif

#ifdef TARGET_OS_FAMILY_solaris

# include "os_solaris.inline.hpp"

#endif

#ifdef TARGET_OS_FAMILY_windows

# include "os_windows.inline.hpp"

#endif

#ifdef TARGET_OS_FAMILY_bsd

# include "os_bsd.inline.hpp"

#endif

# 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

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

  static const char* iso8601_format =

    "%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, iso8601_format,

                                   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 decieded 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(gclog_or_tty, true /* force full GC before heap inspection */,

                                   true /* need_prologue */);

          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::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",

                                      "unable to create new native thread");

      }

      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

  }

  static jboolean onLoaded = JNI_FALSE;

  if (onLoaded) {

    // We may have to wait to fire OnLoad until TLS is initialized.

    if (ThreadLocalStorage::is_initialized()) {

      // The JNI_OnLoad handling is normally done by method load in

      // java.lang.ClassLoader$NativeLibrary, but the VM loads the base library

      // explicitly so we have to check for JNI_OnLoad as well

      const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS;

      JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR(

          JNI_OnLoad_t, dll_lookup(_native_java_library, onLoadSymbols[0]));

      if (JNI_OnLoad != NULL) {

        JavaThread* thread = JavaThread::current();

        ThreadToNativeFromVM ttn(thread);

        HandleMark hm(thread);

        jint ver = (*JNI_OnLoad)(&main_vm, NULL);

        onLoaded = JNI_TRUE;

        if (!Threads::is_supported_jni_version_including_1_1(ver)) {

          vm_exit_during_initialization("Unsupported JNI version");

        }

      }

    }

  }

  return _native_java_library;

}

// --------------------- 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;

}

#ifdef ASSERT

#define space_before             (MallocCushion + sizeof(double))

#define space_after              MallocCushion

#define size_addr_from_base(p)   (size_t*)(p + space_before - sizeof(size_t))

#define size_addr_from_obj(p)    ((size_t*)p - 1)

// MallocCushion: size of extra cushion allocated around objects with +UseMallocOnly

// NB: cannot be debug variable, because these aren't set from the command line until

// *after* the first few allocs already happened

#define MallocCushion            16

#else

#define space_before             0

#define space_after              0

#define size_addr_from_base(p)   should not use w/o ASSERT

#define size_addr_from_obj(p)    should not use w/o ASSERT

#define MallocCushion            0

#endif

#define paranoid                 0  /* only set to 1 if you suspect checking code has bug */

#ifdef ASSERT

inline size_t get_size(void* obj) {

  size_t size = *size_addr_from_obj(obj);

  if (size < 0) {

    fatal(err_msg("free: size field of object #" PTR_FORMAT " was overwritten ("

                  SIZE_FORMAT ")", obj, size));

  }

  return size;

}

u_char* find_cushion_backwards(u_char* start) {

  u_char* p = start;

  while (p[ 0] != badResourceValue || p[-1] != badResourceValue ||

         p[-2] != badResourceValue || p[-3] != badResourceValue) p--;

  // ok, we have four consecutive marker bytes; find start

  u_char* q = p - 4;

  while (*q == badResourceValue) q--;

  return q + 1;

}

u_char* find_cushion_forwards(u_char* start) {

  u_char* p = start;

  while (p[0] != badResourceValue || p[1] != badResourceValue ||

         p[2] != badResourceValue || p[3] != badResourceValue) p++;

  // ok, we have four consecutive marker bytes; find end of cushion

  u_char* q = p + 4;

  while (*q == badResourceValue) q++;

  return q - MallocCushion;

}

void print_neighbor_blocks(void* ptr) {

  // find block allocated before ptr (not entirely crash-proof)

  if (MallocCushion < 4) {

    tty->print_cr("### cannot find previous block (MallocCushion < 4)");

    return;

  }

  u_char* start_of_this_block = (u_char*)ptr - space_before;

  u_char* end_of_prev_block_data = start_of_this_block - space_after -1;

  // look for cushion in front of prev. block

  u_char* start_of_prev_block = find_cushion_backwards(end_of_prev_block_data);

  ptrdiff_t size = *size_addr_from_base(start_of_prev_block);

  u_char* obj = start_of_prev_block + space_before;