rev 7758 : 8065895 Synchronous signals during error reporting may terminate or hang VM process
Reviewed-by: dholmes,gziemski
Contributed-by: stuefe

   1 /*
   2  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "runtime/arguments.hpp"
  27 #include "runtime/os.hpp"
  28 #include "runtime/thread.hpp"
  29 #include "utilities/vmError.hpp"
  30 
  31 #include <sys/types.h>
  32 #include <sys/wait.h>

  33 #include <signal.h>
  34 
  35 void VMError::show_message_box(char *buf, int buflen) {
  36   bool yes;
  37   do {
  38     error_string(buf, buflen);
  39     int len = (int)strlen(buf);
  40     char *p = &buf[len];
  41 
  42     jio_snprintf(p, buflen - len,
  43                "\n\n"
  44                "Do you want to debug the problem?\n\n"
  45                "To debug, run 'dbx - %d'; then switch to thread " INTX_FORMAT "\n"
  46                "Enter 'yes' to launch dbx automatically (PATH must include dbx)\n"
  47                "Otherwise, press RETURN to abort...",
  48                os::current_process_id(), os::current_thread_id());
  49 
  50     yes = os::message_box("Unexpected Error", buf);
  51 
  52     if (yes) {
  53       // yes, user asked VM to launch debugger
  54       jio_snprintf(buf, buflen, "dbx - %d", os::current_process_id());
  55 
  56       os::fork_and_exec(buf);
  57       yes = false;
  58     }
  59   } while (yes);
  60 }
  61 






  62 // Space for our "saved" signal flags and handlers
  63 static int resettedSigflags[2];
  64 static address resettedSighandler[2];
  65 
  66 static void save_signal(int idx, int sig)
  67 {
  68   struct sigaction sa;
  69   sigaction(sig, NULL, &sa);
  70   resettedSigflags[idx]   = sa.sa_flags;
  71   resettedSighandler[idx] = (sa.sa_flags & SA_SIGINFO)
  72                               ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
  73                               : CAST_FROM_FN_PTR(address, sa.sa_handler);
  74 }
  75 
  76 int VMError::get_resetted_sigflags(int sig) {
  77   if(SIGSEGV == sig) {
  78     return resettedSigflags[0];
  79   } else if(SIGBUS == sig) {
  80     return resettedSigflags[1];
  81   }
  82   return -1;
  83 }
  84 
  85 address VMError::get_resetted_sighandler(int sig) {
  86   if(SIGSEGV == sig) {
  87     return resettedSighandler[0];
  88   } else if(SIGBUS == sig) {
  89     return resettedSighandler[1];
  90   }
  91   return NULL;
  92 }
  93 
  94 static void crash_handler(int sig, siginfo_t* info, void* ucVoid) {
  95   // unmask current signal
  96   sigset_t newset;
  97   sigemptyset(&newset);
  98   sigaddset(&newset, sig);
  99   sigprocmask(SIG_UNBLOCK, &newset, NULL);




 100 
 101   VMError err(NULL, sig, NULL, info, ucVoid);
 102   err.report_and_die();
 103 }
 104 
 105 void VMError::reset_signal_handlers() {
 106   // Save sigflags for resetted signals
 107   save_signal(0, SIGSEGV);
 108   save_signal(1, SIGBUS);
 109   os::signal(SIGSEGV, CAST_FROM_FN_PTR(void *, crash_handler));
 110   os::signal(SIGBUS, CAST_FROM_FN_PTR(void *, crash_handler));





 111 }
--- EOF ---