/*

 * Copyright (c) 2003, 2018, 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 "memory/metaspaceShared.hpp"

#include "runtime/arguments.hpp"

#include "runtime/os.hpp"

#include "runtime/thread.hpp"

#include "utilities/vmError.hpp"

#include <sys/types.h>

#include <sys/wait.h>

#include <signal.h>

#ifdef LINUX

#include <sys/syscall.h>

#include <unistd.h>

#endif

#ifdef SOLARIS

#include <thread.h>

#endif

#ifdef AIX

#include <unistd.h>

#endif

#ifdef BSD

#include <sys/syscall.h>

#include <unistd.h>

#endif

// handle all synchronous program error signals which may happen during error

// reporting. They must be unblocked, caught, handled.

static const int SIGNALS[] = { SIGSEGV, SIGBUS, SIGILL, SIGFPE, SIGTRAP }; // add more if needed

static const int NUM_SIGNALS = sizeof(SIGNALS) / sizeof(int);

// Space for our "saved" signal flags and handlers

static int resettedSigflags[NUM_SIGNALS];

static address resettedSighandler[NUM_SIGNALS];

// Needed for cancelable steps.

static volatile pthread_t reporter_thread_id;

void VMError::reporting_started() {

  // record pthread id of reporter thread.

  reporter_thread_id = ::pthread_self();

}

void VMError::interrupt_reporting_thread() {

  // We misuse SIGILL here, but it does not really matter. We need

  //  a signal which is handled by crash_handler and not likely to

  //  occurr during error reporting itself.

  ::pthread_kill(reporter_thread_id, SIGILL);

}

static void save_signal(int idx, int sig)

{

  struct sigaction sa;

  sigaction(sig, NULL, &sa);

  resettedSigflags[idx]   = sa.sa_flags;

  resettedSighandler[idx] = (sa.sa_flags & SA_SIGINFO)

                              ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)

                              : CAST_FROM_FN_PTR(address, sa.sa_handler);

}

int VMError::get_resetted_sigflags(int sig) {

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

    if (SIGNALS[i] == sig) {

      return resettedSigflags[i];

    }

  }

  return -1;

}

address VMError::get_resetted_sighandler(int sig) {

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

    if (SIGNALS[i] == sig) {

      return resettedSighandler[i];

    }

  }

  return NULL;

}

static void crash_handler(int sig, siginfo_t* info, void* ucVoid) {

  // unmask current signal

  sigset_t newset;

  sigemptyset(&newset);

  sigaddset(&newset, sig);

  // also unmask other synchronous signals

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

    sigaddset(&newset, SIGNALS[i]);

  }

  os::Posix::unblock_thread_signal_mask(&newset);

  // support safefetch faults in error handling

  ucontext_t* const uc = (ucontext_t*) ucVoid;

  address pc = (uc != NULL) ? os::Posix::ucontext_get_pc(uc) : NULL;

  // Correct pc for SIGILL, SIGFPE (see JDK-8176872)

  if (sig == SIGILL || sig == SIGFPE) {

    pc = (address) info->si_addr;

  }

  if (uc && pc && StubRoutines::is_safefetch_fault(pc)) {

    os::Posix::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));

    return;

  }

  VMError::report_and_die(NULL, sig, pc, info, ucVoid);

}

void VMError::reset_signal_handlers() {

  // install signal handlers for all synchronous program error signals

  sigset_t newset;

  sigemptyset(&newset);

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

    save_signal(i, SIGNALS[i]);

    os::signal(SIGNALS[i], CAST_FROM_FN_PTR(void *, crash_handler));

    sigaddset(&newset, SIGNALS[i]);

  }

  os::Posix::unblock_thread_signal_mask(&newset);

}

// Write a hint to the stream in case siginfo relates to a segv/bus error

// and the offending address points into CDS archive.

void VMError::check_failing_cds_access(outputStream* st, const void* siginfo) {

#if INCLUDE_CDS

  if (siginfo && UseSharedSpaces) {

    const siginfo_t* const si = (siginfo_t*)siginfo;

    if (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) {

      const void* const fault_addr = si->si_addr;

      if (fault_addr != NULL) {

        if (MetaspaceShared::is_in_shared_metaspace(fault_addr)) {

          st->print("Error accessing class data sharing archive. "

            "Mapped file inaccessible during execution, possible disk/network problem.");

        }

      }

    }

  }

#endif

}