/*

 * Copyright (c) 2003, 2010, 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 "runtime/arguments.hpp"

#include "runtime/os.hpp"

#include "runtime/thread.hpp"

#include "utilities/vmError.hpp"

#include <sys/types.h>

#include <sys/wait.h>

#include <sys/syscall.h>

#include <unistd.h>

#include <signal.h>

void VMError::show_message_box(char *buf, int buflen) {

  bool yes;

  do {

    error_string(buf, buflen);

    int len = (int)strlen(buf);

    char *p = &buf[len];

    jio_snprintf(p, buflen - len,

               "\n\n"

               "Do you want to debug the problem?\n\n"

               "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"

               "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"

               "Otherwise, press RETURN to abort...",

               os::current_process_id(), os::current_process_id(),

               os::current_thread_id(), os::current_thread_id());

    yes = os::message_box("Unexpected Error", buf);

    if (yes) {

      // yes, user asked VM to launch debugger

      jio_snprintf(buf, buflen, "gdb /proc/%d/exe %d",

                   os::current_process_id(), os::current_process_id());

      os::fork_and_exec(buf);

      yes = false;

    }

  } while (yes);

}

// 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];

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]);

  }

  pthread_sigmask(SIG_UNBLOCK, &newset, NULL);

  // support safefetch faults in error handling

  ucontext_t* const uc = (ucontext_t*) ucVoid;

  address const pc = uc ? os::Linux::ucontext_get_pc(uc) : NULL;

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

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

    return;

  }

}

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]);

  }

  pthread_sigmask(SIG_UNBLOCK, &newset, NULL);

}