1 /*
   2  * Copyright (c) 1999, 2013, 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 #ifndef OS_POSIX_VM_OS_POSIX_HPP
  26 #define OS_POSIX_VM_OS_POSIX_HPP
  27 class Posix {
  28   friend class os;
  29 
  30 protected:
  31   static void print_distro_info(outputStream* st);
  32   static void print_rlimit_info(outputStream* st);
  33   static void print_uname_info(outputStream* st);
  34   static void print_libversion_info(outputStream* st);
  35   static void print_load_average(outputStream* st);
  36 
  37 public:
  38 
  39   // Returns true if signal is valid.
  40   static bool is_valid_signal(int sig);
  41 
  42   // Helper function, returns a string (e.g. "SIGILL") for a signal.
  43   // Returned string is a constant. For unknown signals "UNKNOWN" is returned.
  44   static const char* get_signal_name(int sig, char* out, size_t outlen);
  45 
  46   // Returns one-line short description of a signal set in a user provided buffer.
  47   static const char* describe_signal_set_short(const sigset_t* set, char* buffer, size_t size);
  48 
  49   // Prints a short one-line description of a signal set.
  50   static void print_signal_set_short(outputStream* st, const sigset_t* set);
  51 
  52   // Writes a one-line description of a combination of sigaction.sa_flags
  53   // into a user provided buffer. Returns that buffer.
  54   static const char* describe_sa_flags(int flags, char* buffer, size_t size);
  55 
  56   // Prints a one-line description of a combination of sigaction.sa_flags.
  57   static void print_sa_flags(outputStream* st, int flags);
  58 
  59   // A POSIX conform, platform-independend siginfo print routine.
  60   static void print_siginfo_brief(outputStream* os, const siginfo_t* si);
  61 
  62 };
  63 
  64 /*
  65  * Crash protection utility used by JFR. Wrap the callback
  66  * with a sigsetjmp and in case of a SIGSEGV/SIGBUS we siglongjmp
  67  * back.
  68  * To be able to use this - don't take locks, don't rely on destructors,
  69  * don't make OS library calls, don't allocate memory, don't print,
  70  * don't call code that could leave the heap / memory in an inconsistent state,
  71  * or anything else where we are not in control if we suddenly jump out.
  72  */
  73 class ThreadCrashProtection : public StackObj {
  74 public:
  75   static bool is_crash_protected(Thread* thr) {
  76     return _crash_protection != NULL && _protected_thread == thr;
  77   }
  78 
  79   ThreadCrashProtection();
  80   bool call(os::CrashProtectionCallback& cb);
  81 
  82   static void check_crash_protection(int signal, Thread* thread);
  83 private:
  84   static Thread* _protected_thread;
  85   static ThreadCrashProtection* _crash_protection;
  86   static volatile intptr_t _crash_mux;
  87   void restore();
  88   sigjmp_buf _jmpbuf;
  89 };
  90 
  91 #endif // OS_POSIX_VM_OS_POSIX_HPP