/*

 * Copyright 1997-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

# include "incls/_precompiled.incl"

# include "incls/_os.cpp.incl"

# 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;

volatile jlong    os::_global_time        = 0;

volatile int      os::_global_time_lock   = 0;

bool              os::_use_global_time    = false;

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

#ifndef PRODUCT

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

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

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

#endif

// Atomic read of a jlong is assured by a seqlock; see update_global_time()

jlong os::read_global_time() {

#ifdef _LP64

  return _global_time;

#else

  volatile int lock;

  volatile jlong current_time;

  int ctr = 0;

  for (;;) {

    lock = _global_time_lock;

    // spin while locked

    while ((lock & 0x1) != 0) {

      ++ctr;

      if ((ctr & 0xFFF) == 0) {

        // Guarantee writer progress.  Can't use yield; yield is advisory

        // and has almost no effect on some platforms.  Don't need a state

        // transition - the park call will return promptly.

        assert(Thread::current() != NULL, "TLS not initialized");

        assert(Thread::current()->_ParkEvent != NULL, "sync not initialized");

        Thread::current()->_ParkEvent->park(1);

      }

      lock = _global_time_lock;

    }

    OrderAccess::loadload();

    current_time = _global_time;

    OrderAccess::loadload();

    // ratify seqlock value

    if (lock == _global_time_lock) {

      return current_time;

    }

  }

#endif

}

//

// NOTE - Assumes only one writer thread!

//

// We use a seqlock to guarantee that jlong _global_time is updated

// atomically on 32-bit platforms.  A locked value is indicated by

// the lock variable LSB == 1.  Readers will initially read the lock

// value, spinning until the LSB == 0.  They then speculatively read

// the global time value, then re-read the lock value to ensure that

// it hasn't changed.  If the lock value has changed, the entire read

// sequence is retried.

//

// Writers simply set the LSB = 1 (i.e. increment the variable),

// update the global time, then release the lock and bump the version

// number (i.e. increment the variable again.)  In this case we don't

// even need a CAS since we ensure there's only one writer.

//

void os::update_global_time() {

#ifdef _LP64

  _global_time = timeofday();

#else

  assert((_global_time_lock & 0x1) == 0, "multiple writers?");

  jlong current_time = timeofday();

  _global_time_lock++; // lock

  OrderAccess::storestore();

  _global_time = current_time;

  OrderAccess::storestore();

  _global_time_lock++; // unlock

#endif

}

// 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 = timeofday();

  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

  const struct tm *time_struct_temp = localtime(&seconds_since_19700101);

  if (time_struct_temp == NULL) {

    assert(false, "Failed localtime");

    return NULL;

  }

  // Save the results of localtime

  const struct tm time_struct = *time_struct_temp;

  const time_t zone = timezone;

  // 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(3C) 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(3C) 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;

  }

}

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;

  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 */);

          VMThread::execute(&op1);

        }

        if (JvmtiExport::should_post_data_dump()) {

          JvmtiExport::post_data_dump();

        }

        break;

      }

      default: {

        // Dispatch the signal to java

        HandleMark hm(THREAD);

        klassOop k = SystemDictionary::resolve_or_null(vmSymbolHandles::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,

            vmSymbolHandles::dispatch_name(),

            vmSymbolHandles::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;

    klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::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,

                           vmSymbolHandles::object_initializer_name(),

                           vmSymbolHandles::threadgroup_string_void_signature(),

                           thread_group,

                           string,

                           CHECK);

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

    JavaCalls::call_special(&result,

                            thread_group,

                            group,

                            vmSymbolHandles::add_method_name(),

                            vmSymbolHandles::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.

    hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "verify");

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

    // Load java dll

    hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), "java");

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

    if (_native_java_library == NULL) {

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

    }

    // 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, hpi::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);

      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) {

  size_t size = strlen(str);

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

  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 )

    fatal2("free: size field of object #%p was overwritten (%lu)", 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;

  if (size <= 0 ) {

    // start is bad; mayhave been confused by OS data inbetween objects

    // search one more backwards

    start_of_prev_block = find_cushion_backwards(start_of_prev_block);

    size = *size_addr_from_base(start_of_prev_block);

    obj = start_of_prev_block + space_before;

  }

  if (start_of_prev_block + space_before + size + space_after == start_of_this_block) {

    tty->print_cr("### previous object: %p (%ld bytes)", obj, size);

  } else {

    tty->print_cr("### previous object (not sure if correct): %p (%ld bytes)", obj, size);

  }

  // now find successor block

  u_char* start_of_next_block = (u_char*)ptr + *size_addr_from_obj(ptr) + space_after;

  start_of_next_block = find_cushion_forwards(start_of_next_block);

  u_char* next_obj = start_of_next_block + space_before;

  ptrdiff_t next_size = *size_addr_from_base(start_of_next_block);

  if (start_of_next_block[0] == badResourceValue &&