/*

* Copyright (c) 1999, 2013, 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 "prims/jvm.h"

#include "runtime/frame.inline.hpp"

#include "runtime/os.hpp"

#include "utilities/vmError.hpp"

#include <unistd.h>

#include <sys/resource.h>

#include <sys/utsname.h>

#include <pthread.h>

#include <signal.h>

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

void os::check_or_create_dump(void* exceptionRecord, void* contextRecord, char* buffer, size_t bufferSize) {

  int n;

  struct rlimit rlim;

  bool success;

  n = get_core_path(buffer, bufferSize);

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

    jio_snprintf(buffer + n, bufferSize - n, "/core or core.%d (may not exist)", current_process_id());

    success = true;

  } else {

    switch(rlim.rlim_cur) {

      case RLIM_INFINITY:

        jio_snprintf(buffer + n, bufferSize - n, "/core or core.%d", current_process_id());

        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 + n, bufferSize - n, "/core or core.%d (max size %lu kB). To ensure a full core dump, try \"ulimit -c unlimited\" before starting Java again", current_process_id(), (unsigned long)(rlim.rlim_cur >> 10));

        success = true;

        break;

    }

  }

  VMError::report_coredump_status(buffer, success);

}

address os::get_caller_pc(int n) {

#ifdef _NMT_NOINLINE_

  n ++;

#endif

  frame fr = os::current_frame();

  while (n > 0 && fr.pc() &&

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

    fr = os::get_sender_for_C_frame(&fr);

    n --;

  }

  if (n == 0) {

    return fr.pc();

  } else {

    return NULL;

  }

}

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");

  else st->print("%uk", rlim.rlim_cur >> 10);

  st->print(", CORE ");

  getrlimit(RLIMIT_CORE, &rlim);

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

  else st->print("%uk", rlim.rlim_cur >> 10);

  //Isn't there on solaris

#ifndef TARGET_OS_FAMILY_solaris

  st->print(", NPROC ");

  getrlimit(RLIMIT_NPROC, &rlim);

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

  else st->print("%d", rlim.rlim_cur);

#endif

  st->print(", NOFILE ");

  getrlimit(RLIMIT_NOFILE, &rlim);

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

  else st->print("%d", rlim.rlim_cur);

  st->print(", AS ");

  getrlimit(RLIMIT_AS, &rlim);

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

  else st->print("%uk", rlim.rlim_cur >> 10);

  st->cr();

}

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

  // kernel

  st->print("uname:");

  struct utsname name;

  uname(&name);

  st->print(name.sysname); st->print(" ");

  st->print(name.release); st->print(" ");

  st->print(name.version); st->print(" ");

  st->print(name.machine);

  st->cr();

}

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;

}

os::WatcherThreadCrashProtection::WatcherThreadCrashProtection() {

  assert(Thread::current()->is_Watcher_thread(), "Must be WatcherThread");

}

/*

 * See the caveats for this class in os_posix.hpp

 * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this

 * method and returns false. If none of the signals are raised, returns true.

 * The callback is supposed to provide the method that should be protected.

 */

bool os::WatcherThreadCrashProtection::call(os::CrashProtectionCallback& cb) {

  sigset_t saved_sig_mask;

  assert(Thread::current()->is_Watcher_thread(), "Only for WatcherThread");

  assert(!WatcherThread::watcher_thread()->has_crash_protection(),

      "crash_protection already set?");

  // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask

  // since on at least some systems (OS X) siglongjmp will restore the mask

  // for the process, not the thread

  pthread_sigmask(0, NULL, &saved_sig_mask);

  if (sigsetjmp(_jmpbuf, 0) == 0) {

    // make sure we can see in the signal handler that we have crash protection

    // installed

    WatcherThread::watcher_thread()->set_crash_protection(this);

    cb.call();

    // and clear the crash protection

    WatcherThread::watcher_thread()->set_crash_protection(NULL);

    return true;

  }

  // this happens when we siglongjmp() back

  pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL);

  WatcherThread::watcher_thread()->set_crash_protection(NULL);

  return false;

}

void os::WatcherThreadCrashProtection::restore() {

  assert(WatcherThread::watcher_thread()->has_crash_protection(),

      "must have crash protection");

  siglongjmp(_jmpbuf, 1);

}

void os::WatcherThreadCrashProtection::check_crash_protection(int sig,

    Thread* thread) {

  if (thread != NULL &&

      thread->is_Watcher_thread() &&

      WatcherThread::watcher_thread()->has_crash_protection()) {

    if (sig == SIGSEGV || sig == SIGBUS) {

      WatcherThread::watcher_thread()->crash_protection()->restore();

    }

  }

}