/*

 * Copyright (c) 1999, 2014, 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.

 *

 */

// no precompiled headers

#include "classfile/classLoader.hpp"

#include "classfile/systemDictionary.hpp"

#include "classfile/vmSymbols.hpp"

#include "code/icBuffer.hpp"

#include "code/vtableStubs.hpp"

#include "compiler/compileBroker.hpp"

#include "compiler/disassembler.hpp"

#include "interpreter/interpreter.hpp"

#include "jvm_linux.h"

#include "memory/allocation.inline.hpp"

#include "memory/filemap.hpp"

#include "mutex_linux.inline.hpp"

#include "oops/oop.inline.hpp"

#include "os_share_linux.hpp"

#include "prims/jniFastGetField.hpp"

#include "prims/jvm.h"

#include "prims/jvm_misc.hpp"

#include "runtime/arguments.hpp"

#include "runtime/extendedPC.hpp"

#include "runtime/globals.hpp"

#include "runtime/interfaceSupport.hpp"

#include "runtime/init.hpp"

#include "runtime/java.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/objectMonitor.hpp"

#include "runtime/osThread.hpp"

#include "runtime/perfMemory.hpp"

#include "runtime/sharedRuntime.hpp"

#include "runtime/statSampler.hpp"

#include "runtime/stubRoutines.hpp"

#include "runtime/thread.inline.hpp"

#include "runtime/threadCritical.hpp"

#include "runtime/timer.hpp"

#include "services/attachListener.hpp"

#include "services/memTracker.hpp"

#include "services/runtimeService.hpp"

#include "utilities/decoder.hpp"

#include "utilities/defaultStream.hpp"

#include "utilities/events.hpp"

#include "utilities/elfFile.hpp"

#include "utilities/growableArray.hpp"

#include "utilities/vmError.hpp"

// put OS-includes here

# include <sys/types.h>

# include <sys/mman.h>

# include <sys/stat.h>

# include <sys/select.h>

# include <pthread.h>

# include <signal.h>

# include <errno.h>

# include <dlfcn.h>

# include <stdio.h>

# include <unistd.h>

# include <sys/resource.h>

# include <pthread.h>

# include <sys/stat.h>

# include <sys/time.h>

# include <sys/times.h>

# include <sys/utsname.h>

# include <sys/socket.h>

# include <sys/wait.h>

# include <pwd.h>

# include <poll.h>

# include <semaphore.h>

# include <fcntl.h>

# include <string.h>

# include <syscall.h>

# include <sys/sysinfo.h>

# include <gnu/libc-version.h>

# include <sys/ipc.h>

# include <sys/shm.h>

# include <link.h>

# include <stdint.h>

# include <inttypes.h>

# include <sys/ioctl.h>

// if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling

// getrusage() is prepared to handle the associated failure.

#ifndef RUSAGE_THREAD

#define RUSAGE_THREAD   (1)               /* only the calling thread */

#endif

#define MAX_PATH    (2 * K)

#define MAX_SECS 100000000

// for timer info max values which include all bits

#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)

#define LARGEPAGES_BIT (1 << 6)

////////////////////////////////////////////////////////////////////////////////

// global variables

julong os::Linux::_physical_memory = 0;

address   os::Linux::_initial_thread_stack_bottom = NULL;

uintptr_t os::Linux::_initial_thread_stack_size   = 0;

int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;

int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;

Mutex* os::Linux::_createThread_lock = NULL;

pthread_t os::Linux::_main_thread;

int os::Linux::_page_size = -1;

const int os::Linux::_vm_default_page_size = (8 * K);

bool os::Linux::_is_floating_stack = false;

bool os::Linux::_is_NPTL = false;

bool os::Linux::_supports_fast_thread_cpu_time = false;

const char * os::Linux::_glibc_version = NULL;

const char * os::Linux::_libpthread_version = NULL;

pthread_condattr_t os::Linux::_condattr[1];

static jlong initial_time_count=0;

static int clock_tics_per_sec = 100;

// For diagnostics to print a message once. see run_periodic_checks

static sigset_t check_signal_done;

static bool check_signals = true;

static pid_t _initial_pid = 0;

/* Signal number used to suspend/resume a thread */

/* do not use any signal number less than SIGSEGV, see 4355769 */

static int SR_signum = SIGUSR2;

sigset_t SR_sigset;

/* Used to protect dlsym() calls */

static pthread_mutex_t dl_mutex;

// Declarations

static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);

#ifdef JAVASE_EMBEDDED

class MemNotifyThread: public Thread {

  friend class VMStructs;

 public:

  virtual void run();

 private:

  static MemNotifyThread* _memnotify_thread;

  int _fd;

 public:

  // Constructor

  MemNotifyThread(int fd);

  // Tester

  bool is_memnotify_thread() const { return true; }

  // Printing

  char* name() const { return (char*)"Linux MemNotify Thread"; }

  // Returns the single instance of the MemNotifyThread

  static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }

  // Create and start the single instance of MemNotifyThread

  static void start();

};

#endif // JAVASE_EMBEDDED

// utility functions

static int SR_initialize();

julong os::available_memory() {

  return Linux::available_memory();

}

julong os::Linux::available_memory() {

  // values in struct sysinfo are "unsigned long"

  struct sysinfo si;

  sysinfo(&si);

  return (julong)si.freeram * si.mem_unit;

}

julong os::physical_memory() {

  return Linux::physical_memory();

}

////////////////////////////////////////////////////////////////////////////////

// environment support

bool os::getenv(const char* name, char* buf, int len) {

  const char* val = ::getenv(name);

  if (val != NULL && strlen(val) < (size_t)len) {

    strcpy(buf, val);

    return true;

  }

  if (len > 0) buf[0] = 0;  // return a null string

  return false;

}

// Return true if user is running as root.

bool os::have_special_privileges() {

  static bool init = false;

  static bool privileges = false;

  if (!init) {

    privileges = (getuid() != geteuid()) || (getgid() != getegid());

    init = true;

  }

  return privileges;

}

#ifndef SYS_gettid

// i386: 224, ia64: 1105, amd64: 186, sparc 143

#ifdef __ia64__

#define SYS_gettid 1105

#elif __i386__

#define SYS_gettid 224

#elif __amd64__

#define SYS_gettid 186

#elif __sparc__

#define SYS_gettid 143

#else

#error define gettid for the arch

#endif

#endif

// Cpu architecture string

#if   defined(ZERO)

static char cpu_arch[] = ZERO_LIBARCH;

#elif defined(IA64)

static char cpu_arch[] = "ia64";

#elif defined(IA32)

static char cpu_arch[] = "i386";

#elif defined(AMD64)

static char cpu_arch[] = "amd64";

#elif defined(ARM)

static char cpu_arch[] = "arm";

#elif defined(PPC32)

static char cpu_arch[] = "ppc";

#elif defined(PPC64)

static char cpu_arch[] = "ppc64";

#elif defined(SPARC)

#  ifdef _LP64

static char cpu_arch[] = "sparcv9";

#  else

static char cpu_arch[] = "sparc";

#  endif

#else

#error Add appropriate cpu_arch setting

#endif

// pid_t gettid()

//

// Returns the kernel thread id of the currently running thread. Kernel

// thread id is used to access /proc.

//

// (Note that getpid() on LinuxThreads returns kernel thread id too; but

// on NPTL, it returns the same pid for all threads, as required by POSIX.)

//

pid_t os::Linux::gettid() {

  int rslt = syscall(SYS_gettid);

  if (rslt == -1) {

     // old kernel, no NPTL support

     return getpid();

  } else {

     return (pid_t)rslt;

  }

}

// Most versions of linux have a bug where the number of processors are

// determined by looking at the /proc file system.  In a chroot environment,

// the system call returns 1.  This causes the VM to act as if it is

// a single processor and elide locking (see is_MP() call).

static bool unsafe_chroot_detected = false;

static const char *unstable_chroot_error = "/proc file system not found.\n"

                     "Java may be unstable running multithreaded in a chroot "

                     "environment on Linux when /proc filesystem is not mounted.";

void os::Linux::initialize_system_info() {

  set_processor_count(sysconf(_SC_NPROCESSORS_CONF));

  if (processor_count() == 1) {

    pid_t pid = os::Linux::gettid();

    char fname[32];

    jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);

    FILE *fp = fopen(fname, "r");

    if (fp == NULL) {

      unsafe_chroot_detected = true;

    } else {

      fclose(fp);

    }

  }

  _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);

  assert(processor_count() > 0, "linux error");

}

void os::init_system_properties_values() {

  // The next steps are taken in the product version:

  //

  // Obtain the JAVA_HOME value from the location of libjvm.so.

  // This library should be located at:

  // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.

  //

  // If "/jre/lib/" appears at the right place in the path, then we

  // assume libjvm.so is installed in a JDK and we use this path.

  //

  // Otherwise exit with message: "Could not create the Java virtual machine."

  //

  // The following extra steps are taken in the debugging version:

  //

  // If "/jre/lib/" does NOT appear at the right place in the path

  // instead of exit check for $JAVA_HOME environment variable.

  //

  // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,

  // then we append a fake suffix "hotspot/libjvm.so" to this path so

  // it looks like libjvm.so is installed there

  // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.

  //

  // Otherwise exit.

  //

  // Important note: if the location of libjvm.so changes this

  // code needs to be changed accordingly.

#if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))

#define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"

#else

#define DEFAULT_LIBPATH "/lib:/usr/lib"

#endif

#define EXTENSIONS_DIR  "/lib/ext"

#define ENDORSED_DIR    "/lib/endorsed"

  {

        pslash = strrchr(buf, '/');

        if (pslash != NULL) {

        }

    }

#undef EXTENSIONS_DIR

#undef ENDORSED_DIR

}

////////////////////////////////////////////////////////////////////////////////

// breakpoint support

void os::breakpoint() {

  BREAKPOINT;

}

extern "C" void breakpoint() {

  // use debugger to set breakpoint here

}

////////////////////////////////////////////////////////////////////////////////

// signal support

debug_only(static bool signal_sets_initialized = false);

static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;

bool os::Linux::is_sig_ignored(int sig) {

      struct sigaction oact;

      sigaction(sig, (struct sigaction*)NULL, &oact);

      void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*,  oact.sa_sigaction)

                                     : CAST_FROM_FN_PTR(void*,  oact.sa_handler);

      if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))

           return true;

      else

           return false;

}

void os::Linux::signal_sets_init() {

  // Should also have an assertion stating we are still single-threaded.

  assert(!signal_sets_initialized, "Already initialized");

  // Fill in signals that are necessarily unblocked for all threads in

  // the VM. Currently, we unblock the following signals:

  // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden

  //                         by -Xrs (=ReduceSignalUsage));

  // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all

  // other threads. The "ReduceSignalUsage" boolean tells us not to alter

  // the dispositions or masks wrt these signals.

  // Programs embedding the VM that want to use the above signals for their

  // own purposes must, at this time, use the "-Xrs" option to prevent

  // interference with shutdown hooks and BREAK_SIGNAL thread dumping.

  // (See bug 4345157, and other related bugs).

  // In reality, though, unblocking these signals is really a nop, since

  // these signals are not blocked by default.

  sigemptyset(&unblocked_sigs);

  sigemptyset(&allowdebug_blocked_sigs);

  sigaddset(&unblocked_sigs, SIGILL);

  sigaddset(&unblocked_sigs, SIGSEGV);

  sigaddset(&unblocked_sigs, SIGBUS);

  sigaddset(&unblocked_sigs, SIGFPE);

#if defined(PPC64)

  sigaddset(&unblocked_sigs, SIGTRAP);

#endif

  sigaddset(&unblocked_sigs, SR_signum);

  if (!ReduceSignalUsage) {

   if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {

      sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);

      sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);

   }

   if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {

      sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);

      sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);

   }

   if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {