/*

 * Copyright (c) 1999, 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 "utilities/globalDefinitions.hpp"

#include "prims/jvm.h"

#include "semaphore_posix.hpp"

#include "runtime/frame.inline.hpp"

#include "runtime/interfaceSupport.hpp"

#include "runtime/os.hpp"

#include "utilities/vmError.hpp"

#include <signal.h>

#include <unistd.h>

#include <sys/resource.h>

#include <sys/utsname.h>

#include <pthread.h>

#include <semaphore.h>

#include <signal.h>

// Todo: provide a os::get_max_process_id() or similar. Number of processes

// may have been configured, can be read more accurately from proc fs etc.

#ifndef MAX_PID

#define MAX_PID INT_MAX

#endif

#define IS_VALID_PID(p) (p > 0 && p < MAX_PID)

// Check core dump limit and report possible place where core can be found

void os::check_dump_limit(char* buffer, size_t bufferSize) {

  int n;

  struct rlimit rlim;

  bool success;

  char core_path[PATH_MAX];

  n = get_core_path(core_path, PATH_MAX);

  if (n <= 0) {

    jio_snprintf(buffer, bufferSize, "core.%d (may not exist)", current_process_id());

    success = true;

#ifdef LINUX

  } else if (core_path[0] == '"') { // redirect to user process

    jio_snprintf(buffer, bufferSize, "Core dumps may be processed with %s", core_path);

    success = true;

#endif

  } else if (getrlimit(RLIMIT_CORE, &rlim) != 0) {

    jio_snprintf(buffer, bufferSize, "%s (may not exist)", core_path);

    success = true;

  } else {

    switch(rlim.rlim_cur) {

      case RLIM_INFINITY:

        jio_snprintf(buffer, bufferSize, "%s", core_path);

        success = true;

        break;

      case 0:

        jio_snprintf(buffer, bufferSize, "Core dumps have been disabled. To enable core dumping, try \"ulimit -c unlimited\" before starting Java again");

        success = false;

        break;

      default:

        jio_snprintf(buffer, bufferSize, "%s (max size %lu kB). To ensure a full core dump, try \"ulimit -c unlimited\" before starting Java again", core_path, (unsigned long)(rlim.rlim_cur >> 10));

        success = true;

        break;

    }

  }

  VMError::record_coredump_status(buffer, success);

}

int os::get_native_stack(address* stack, int frames, int toSkip) {

#ifdef _NMT_NOINLINE_

  toSkip++;

#endif

  int frame_idx = 0;

  int num_of_frames;  // number of frames captured

  frame fr = os::current_frame();

  while (fr.pc() && frame_idx < frames) {

    if (toSkip > 0) {

      toSkip --;

    } else {

      stack[frame_idx ++] = fr.pc();

    }

    if (fr.fp() == NULL || fr.cb() != NULL ||

        fr.sender_pc() == NULL || os::is_first_C_frame(&fr)) break;

    if (fr.sender_pc() && !os::is_first_C_frame(&fr)) {

      fr = os::get_sender_for_C_frame(&fr);

    } else {

      break;

    }

  }

  num_of_frames = frame_idx;

  for (; frame_idx < frames; frame_idx ++) {

    stack[frame_idx] = NULL;

  }

  return num_of_frames;

}

bool os::unsetenv(const char* name) {

  assert(name != NULL, "Null pointer");

  return (::unsetenv(name) == 0);

}

int os::get_last_error() {

  return errno;

}

bool os::is_debugger_attached() {

  // not implemented

  return false;

}

void os::wait_for_keypress_at_exit(void) {

  // don't do anything on posix platforms

  return;

}

// Multiple threads can race in this code, and can remap over each other with MAP_FIXED,

// so on posix, unmap the section at the start and at the end of the chunk that we mapped

// rather than unmapping and remapping the whole chunk to get requested alignment.

char* os::reserve_memory_aligned(size_t size, size_t alignment) {

  assert((alignment & (os::vm_allocation_granularity() - 1)) == 0,

      "Alignment must be a multiple of allocation granularity (page size)");

  assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned");

  size_t extra_size = size + alignment;

  assert(extra_size >= size, "overflow, size is too large to allow alignment");

  char* extra_base = os::reserve_memory(extra_size, NULL, alignment);

  if (extra_base == NULL) {

    return NULL;

  }

  // Do manual alignment

  char* aligned_base = (char*) align_size_up((uintptr_t) extra_base, alignment);

  // [  |                                       |  ]

  // ^ extra_base

  //    ^ extra_base + begin_offset == aligned_base

  //     extra_base + begin_offset + size       ^

  //                       extra_base + extra_size ^

  // |<>| == begin_offset

  //                              end_offset == |<>|

  size_t begin_offset = aligned_base - extra_base;

  size_t end_offset = (extra_base + extra_size) - (aligned_base + size);

  if (begin_offset > 0) {

      os::release_memory(extra_base, begin_offset);

  }

  if (end_offset > 0) {

      os::release_memory(extra_base + begin_offset + size, end_offset);

  }

  return aligned_base;

}

void os::Posix::print_load_average(outputStream* st) {

  st->print("load average:");

  double loadavg[3];

  os::loadavg(loadavg, 3);

  st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);

  st->cr();

}

void os::Posix::print_rlimit_info(outputStream* st) {

  st->print("rlimit:");

  struct rlimit rlim;

  st->print(" STACK ");

  getrlimit(RLIMIT_STACK, &rlim);

  if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");

  st->print(", CORE ");

  getrlimit(RLIMIT_CORE, &rlim);

  if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");

  // Isn't there on solaris

#if !defined(TARGET_OS_FAMILY_solaris) && !defined(TARGET_OS_FAMILY_aix)

  st->print(", NPROC ");

  getrlimit(RLIMIT_NPROC, &rlim);

  if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");

#endif

  st->print(", NOFILE ");

  getrlimit(RLIMIT_NOFILE, &rlim);

  if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");

  st->print(", AS ");

  getrlimit(RLIMIT_AS, &rlim);

  if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");

  st->cr();

}

void os::Posix::print_uname_info(outputStream* st) {

  // kernel

  st->print("uname:");

  struct utsname name;

  uname(&name);

  st->print("%s ", name.sysname);

#ifdef ASSERT

  st->print("%s ", name.nodename);

#endif

  st->print("%s ", name.release);

  st->print("%s ", name.version);

  st->print("%s", name.machine);

  st->cr();

}

#ifndef PRODUCT

bool os::get_host_name(char* buf, size_t buflen) {

  struct utsname name;

  uname(&name);

  jio_snprintf(buf, buflen, "%s", name.nodename);

  return true;

}

#endif // PRODUCT

bool os::has_allocatable_memory_limit(julong* limit) {

  struct rlimit rlim;

  int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);

  // if there was an error when calling getrlimit, assume that there is no limitation

  // on virtual memory.

  bool result;

  if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {

    result = false;

  } else {

    *limit = (julong)rlim.rlim_cur;

    result = true;

  }

#ifdef _LP64

  return result;

#else

  // arbitrary virtual space limit for 32 bit Unices found by testing. If

  // getrlimit above returned a limit, bound it with this limit. Otherwise

  // directly use it.

  const julong max_virtual_limit = (julong)3800*M;

  if (result) {

    *limit = MIN2(*limit, max_virtual_limit);

  } else {

    *limit = max_virtual_limit;

  }

  // bound by actually allocatable memory. The algorithm uses two bounds, an

  // upper and a lower limit. The upper limit is the current highest amount of

  // memory that could not be allocated, the lower limit is the current highest

  // amount of memory that could be allocated.

  // The algorithm iteratively refines the result by halving the difference

  // between these limits, updating either the upper limit (if that value could

  // not be allocated) or the lower limit (if the that value could be allocated)

  // until the difference between these limits is "small".

  // the minimum amount of memory we care about allocating.

  const julong min_allocation_size = M;

  julong upper_limit = *limit;

  // first check a few trivial cases

  if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {

    *limit = upper_limit;

  } else if (!is_allocatable(min_allocation_size)) {

    // we found that not even min_allocation_size is allocatable. Return it

    // anyway. There is no point to search for a better value any more.

    *limit = min_allocation_size;

  } else {

    // perform the binary search.

    julong lower_limit = min_allocation_size;

    while ((upper_limit - lower_limit) > min_allocation_size) {

      julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;

      temp_limit = align_size_down_(temp_limit, min_allocation_size);

      if (is_allocatable(temp_limit)) {

        lower_limit = temp_limit;

      } else {

        upper_limit = temp_limit;

      }

    }

    *limit = lower_limit;

  }

  return true;

#endif

}

const char* os::get_current_directory(char *buf, size_t buflen) {

  return getcwd(buf, buflen);

}

FILE* os::open(int fd, const char* mode) {

  return ::fdopen(fd, mode);

}

// Builds a platform dependent Agent_OnLoad_<lib_name> function name

// which is used to find statically linked in agents.

// Parameters:

//            sym_name: Symbol in library we are looking for

//            lib_name: Name of library to look in, NULL for shared libs.

//            is_absolute_path == true if lib_name is absolute path to agent

//                                     such as "/a/b/libL.so"

//            == false if only the base name of the library is passed in

//               such as "L"

char* os::build_agent_function_name(const char *sym_name, const char *lib_name,

                                    bool is_absolute_path) {

  char *agent_entry_name;

  size_t len;

  size_t name_len;

  size_t prefix_len = strlen(JNI_LIB_PREFIX);

  size_t suffix_len = strlen(JNI_LIB_SUFFIX);

  const char *start;

  if (lib_name != NULL) {

    len = name_len = strlen(lib_name);

    if (is_absolute_path) {

      // Need to strip path, prefix and suffix

      if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {

        lib_name = ++start;

      }

      if (len <= (prefix_len + suffix_len)) {

        return NULL;

      }

      lib_name += prefix_len;

      name_len = strlen(lib_name) - suffix_len;

    }

  }

  len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;

  agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);

  if (agent_entry_name == NULL) {

    return NULL;

  }

  strcpy(agent_entry_name, sym_name);

  if (lib_name != NULL) {

    strcat(agent_entry_name, "_");

    strncat(agent_entry_name, lib_name, name_len);

  }

  return agent_entry_name;

}

int os::sleep(Thread* thread, jlong millis, bool interruptible) {

  assert(thread == Thread::current(),  "thread consistency check");

  ParkEvent * const slp = thread->_SleepEvent ;

  slp->reset() ;

  OrderAccess::fence() ;

  if (interruptible) {

    jlong prevtime = javaTimeNanos();

    for (;;) {

      if (os::is_interrupted(thread, true)) {

        return OS_INTRPT;

      }

      jlong newtime = javaTimeNanos();

      if (newtime - prevtime < 0) {

        // time moving backwards, should only happen if no monotonic clock

        // not a guarantee() because JVM should not abort on kernel/glibc bugs

        assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected in os::sleep(interruptible)");

      } else {

        millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;

      }

      if (millis <= 0) {

        return OS_OK;

      }

      prevtime = newtime;

      {

        assert(thread->is_Java_thread(), "sanity check");

        JavaThread *jt = (JavaThread *) thread;

        ThreadBlockInVM tbivm(jt);

        OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);

        jt->set_suspend_equivalent();

        // cleared by handle_special_suspend_equivalent_condition() or

        // java_suspend_self() via check_and_wait_while_suspended()

        slp->park(millis);

        // were we externally suspended while we were waiting?

        jt->check_and_wait_while_suspended();

      }

    }

  } else {

    OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);

    jlong prevtime = javaTimeNanos();

    for (;;) {

      // It'd be nice to avoid the back-to-back javaTimeNanos() calls on

      // the 1st iteration ...

      jlong newtime = javaTimeNanos();

      if (newtime - prevtime < 0) {

        // time moving backwards, should only happen if no monotonic clock

        // not a guarantee() because JVM should not abort on kernel/glibc bugs

        assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected on os::sleep(!interruptible)");

      } else {

        millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;

      }

      if (millis <= 0) break ;

      prevtime = newtime;

      slp->park(millis);

    }

    return OS_OK ;

  }

}

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

// interrupt support

void os::interrupt(Thread* thread) {

  assert(Thread::current() == thread || Threads_lock->owned_by_self(),

    "possibility of dangling Thread pointer");

  OSThread* osthread = thread->osthread();

  if (!osthread->interrupted()) {

    osthread->set_interrupted(true);

    // More than one thread can get here with the same value of osthread,

    // resulting in multiple notifications.  We do, however, want the store

    // to interrupted() to be visible to other threads before we execute unpark().

    OrderAccess::fence();

    ParkEvent * const slp = thread->_SleepEvent ;

    if (slp != NULL) slp->unpark() ;

  }

  // For JSR166. Unpark even if interrupt status already was set

  if (thread->is_Java_thread())

    ((JavaThread*)thread)->parker()->unpark();

  ParkEvent * ev = thread->_ParkEvent ;

  if (ev != NULL) ev->unpark() ;

}

bool os::is_interrupted(Thread* thread, bool clear_interrupted) {

  assert(Thread::current() == thread || Threads_lock->owned_by_self(),

    "possibility of dangling Thread pointer");

  OSThread* osthread = thread->osthread();

  bool interrupted = osthread->interrupted();

  // NOTE that since there is no "lock" around the interrupt and

  // is_interrupted operations, there is the possibility that the

  // interrupted flag (in osThread) will be "false" but that the

  // low-level events will be in the signaled state. This is

  // intentional. The effect of this is that Object.wait() and

  // LockSupport.park() will appear to have a spurious wakeup, which

  // is allowed and not harmful, and the possibility is so rare that

  // it is not worth the added complexity to add yet another lock.

  // For the sleep event an explicit reset is performed on entry

  // to os::sleep, so there is no early return. It has also been

  // recommended not to put the interrupted flag into the "event"

  // structure because it hides the issue.

  if (interrupted && clear_interrupted) {

    osthread->set_interrupted(false);

    // consider thread->_SleepEvent->reset() ... optional optimization

  }

  return interrupted;

}

// Returned string is a constant. For unknown signals "UNKNOWN" is returned.