/*

 * 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 "jvm.h"

#include "classfile/classLoader.hpp"

#include "classfile/javaClasses.hpp"

#include "classfile/moduleEntry.hpp"

#include "classfile/systemDictionary.hpp"

#include "classfile/vmSymbols.hpp"

#include "code/codeCache.hpp"

#include "code/icBuffer.hpp"

#include "code/vtableStubs.hpp"

#include "gc/shared/gcVMOperations.hpp"

#include "logging/log.hpp"

#include "interpreter/interpreter.hpp"

#include "logging/log.hpp"

#include "logging/logStream.hpp"

#include "memory/allocation.inline.hpp"

#ifdef ASSERT

#include "memory/guardedMemory.hpp"

#endif

#include "memory/resourceArea.hpp"

#include "oops/oop.inline.hpp"

#include "prims/jvm_misc.hpp"

#include "runtime/arguments.hpp"

#include "runtime/atomic.hpp"

#include "runtime/frame.inline.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/interfaceSupport.inline.hpp"

#include "runtime/java.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/os.inline.hpp"

#include "runtime/sharedRuntime.hpp"

#include "runtime/stubRoutines.hpp"

#include "runtime/thread.inline.hpp"

#include "runtime/threadSMR.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/align.hpp"

#include "utilities/defaultStream.hpp"

#include "utilities/events.hpp"

# include <signal.h>

# include <errno.h>

OSThread*         os::_starting_thread    = NULL;

address           os::_polling_page       = NULL;

volatile unsigned int os::_rand_seed      = 1;

int               os::_processor_count    = 0;

int               os::_initial_active_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 size_t cur_malloc_words = 0;  // current size for MallocMaxTestWords

DEBUG_ONLY(bool os::_mutex_init_done = false;)

void os_init_globals() {

  // Called from init_globals().

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

  os::init_globals();

}

static time_t get_timezone(const struct tm* time_struct) {

#if defined(_ALLBSD_SOURCE)

  return time_struct->tm_gmtoff;

#elif defined(_WINDOWS)

  long zone;

  _get_timezone(&zone);

  return static_cast<time_t>(zone);

#else

  return timezone;

#endif

}

int os::snprintf(char* buf, size_t len, const char* fmt, ...) {

  va_list args;

  va_start(args, fmt);

  int result = os::vsnprintf(buf, len, fmt, args);

  va_end(args);

  return result;

}

// 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, bool utc) {

  // 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 (utc) {

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

      assert(false, "Failed gmtime_pd");

      return NULL;

    }

  } else {

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

      assert(false, "Failed localtime_pd");

      return NULL;

    }

  }

  const time_t zone = get_timezone(&time_struct);

  // 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;

  }

  // No offset when dealing with UTC

  if (utc) {

    UTC_to_local = 0;

  }

  // 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) {

  debug_only(Thread::check_for_dangling_thread_pointer(thread);)

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

      (p == CriticalPriority && thread->is_ConcurrentGC_thread())) {

    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;

}

bool os::dll_build_name(char* buffer, size_t size, const char* fname) {

  int n = jio_snprintf(buffer, size, "%s%s%s", JNI_LIB_PREFIX, fname, JNI_LIB_SUFFIX);

  return (n != -1);

}

#if !defined(LINUX) && !defined(_WINDOWS)

bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {

  committed_start = start;

  committed_size = size;

  return true;

}

#endif

// Helper for dll_locate_lib.

// Pass buffer and printbuffer as we already printed the path to buffer

// when we called get_current_directory. This way we avoid another buffer

// of size MAX_PATH.

static bool conc_path_file_and_check(char *buffer, char *printbuffer, size_t printbuflen,

                                     const char* pname, char lastchar, const char* fname) {

  // Concatenate path and file name, but don't print double path separators.

  const char *filesep = (WINDOWS_ONLY(lastchar == ':' ||) lastchar == os::file_separator()[0]) ?

                        "" : os::file_separator();

  int ret = jio_snprintf(printbuffer, printbuflen, "%s%s%s", pname, filesep, fname);

  // Check whether file exists.

  if (ret != -1) {

    struct stat statbuf;

    return os::stat(buffer, &statbuf) == 0;

  }

  return false;

}

bool os::dll_locate_lib(char *buffer, size_t buflen,

                        const char* pname, const char* fname) {

  bool retval = false;

  size_t fullfnamelen = strlen(JNI_LIB_PREFIX) + strlen(fname) + strlen(JNI_LIB_SUFFIX);

  char* fullfname = (char*)NEW_C_HEAP_ARRAY(char, fullfnamelen + 1, mtInternal);

  if (dll_build_name(fullfname, fullfnamelen + 1, fname)) {

    const size_t pnamelen = pname ? strlen(pname) : 0;

    if (pnamelen == 0) {

      // If no path given, use current working directory.

      const char* p = get_current_directory(buffer, buflen);

      if (p != NULL) {

        const size_t plen = strlen(buffer);

        const char lastchar = buffer[plen - 1];

        retval = conc_path_file_and_check(buffer, &buffer[plen], buflen - plen,

                                          "", lastchar, fullfname);

      }

    } else if (strchr(pname, *os::path_separator()) != NULL) {

      // A list of paths. Search for the path that contains the library.

      int n;

      char** pelements = split_path(pname, &n);

      if (pelements != NULL) {

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

          char* path = pelements[i];

          // Really shouldn't be NULL, but check can't hurt.

          size_t plen = (path == NULL) ? 0 : strlen(path);

          if (plen == 0) {

            continue; // Skip the empty path values.

          }

          const char lastchar = path[plen - 1];

          retval = conc_path_file_and_check(buffer, buffer, buflen, path, lastchar, fullfname);

          if (retval) break;

        }

        // Release the storage allocated by split_path.

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

          if (pelements[i] != NULL) {

            FREE_C_HEAP_ARRAY(char, pelements[i]);

          }

        }

        FREE_C_HEAP_ARRAY(char*, pelements);

      }

    } else {

      // A definite path.

      const char lastchar = pname[pnamelen-1];

      retval = conc_path_file_and_check(buffer, buffer, buflen, pname, lastchar, fullfname);

    }

  }

  FREE_C_HEAP_ARRAY(char*, fullfname);

  return retval;

}

// --------------------- 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* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_misc_Signal(), THREAD);

        if (klass != 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() {

  initialize_initial_active_processor_count();

  // 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();

  // We need to adapt the configured number of stack protection pages given

  // in 4K pages to the actual os page size. We must do this before setting

  // up minimal stack sizes etc. in os::init_2().

  JavaThread::set_stack_red_zone_size     (align_up(StackRedPages      * 4 * K, vm_page_size()));

  JavaThread::set_stack_yellow_zone_size  (align_up(StackYellowPages   * 4 * K, vm_page_size()));

  JavaThread::set_stack_reserved_zone_size(align_up(StackReservedPages * 4 * K, vm_page_size()));

  JavaThread::set_stack_shadow_zone_size  (align_up(StackShadowPages   * 4 * K, vm_page_size()));

  // VM version initialization identifies some characteristics of the

  // platform that are used during ergonomic decisions.

  VM_Version::init_before_ergo();

}

void os::initialize_jdk_signal_support(TRAPS) {

  if (!ReduceSignalUsage) {

    // Setup JavaThread for processing signals

    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());

    Handle thread_oop = JavaCalls::construct_new_instance(SystemDictionary::Thread_klass(),

                           vmSymbols::threadgroup_string_void_signature(),

                           thread_group,

                           string,

                           CHECK);

    Klass* group = SystemDictionary::ThreadGroup_klass();

    JavaValue result(T_VOID);

    JavaCalls::call_special(&result,

                            thread_group,

                            group,

                            vmSymbols::add_method_name(),

                            vmSymbols::thread_void_signature(),

                            thread_oop,

                            CHECK);

    { 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 ---------------------