os_posix.hpp revision 10367:1c53edac6621 
1/*
2 * Copyright (c) 1999, 2014, 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 "runtime/os.hpp"
26
27#ifndef OS_POSIX_VM_OS_POSIX_HPP
28#define OS_POSIX_VM_OS_POSIX_HPP
29
30// File conventions
31static const char* file_separator() { return "/"; }
32static const char* line_separator() { return "\n"; }
33static const char* path_separator() { return ":"; }
34
35class Posix {
36  friend class os;
37
38protected:
39  static void print_distro_info(outputStream* st);
40  static void print_rlimit_info(outputStream* st);
41  static void print_uname_info(outputStream* st);
42  static void print_libversion_info(outputStream* st);
43  static void print_load_average(outputStream* st);
44
45public:
46
47  // Returns true if signal is valid.
48  static bool is_valid_signal(int sig);
49
50  // Helper function, returns a string (e.g. "SIGILL") for a signal.
51  // Returned string is a constant. For unknown signals "UNKNOWN" is returned.
52  static const char* get_signal_name(int sig, char* out, size_t outlen);
53
54  // Helper function, returns a signal number for a given signal name, e.g. 11
55  // for "SIGSEGV". Name can be given with or without "SIG" prefix, so both
56  // "SEGV" or "SIGSEGV" work. Name must be uppercase.
57  // Returns -1 for an unknown signal name.
58  static int get_signal_number(const char* signal_name);
59
60  // Returns one-line short description of a signal set in a user provided buffer.
61  static const char* describe_signal_set_short(const sigset_t* set, char* buffer, size_t size);
62
63  // Prints a short one-line description of a signal set.
64  static void print_signal_set_short(outputStream* st, const sigset_t* set);
65
66  // unblocks the signal masks for current thread
67  static int unblock_thread_signal_mask(const sigset_t *set);
68
69  // Writes a one-line description of a combination of sigaction.sa_flags
70  // into a user provided buffer. Returns that buffer.
71  static const char* describe_sa_flags(int flags, char* buffer, size_t size);
72
73  // Prints a one-line description of a combination of sigaction.sa_flags.
74  static void print_sa_flags(outputStream* st, int flags);
75
76  static address ucontext_get_pc(const ucontext_t* ctx);
77  // Set PC into context. Needed for continuation after signal.
78  static void ucontext_set_pc(ucontext_t* ctx, address pc);
79
80  // Helper function; describes pthread attributes as short string. String is written
81  // to buf with len buflen; buf is returned.
82  static char* describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr);
83
84};
85
86/*
87 * Crash protection for the watcher thread. Wrap the callback
88 * with a sigsetjmp and in case of a SIGSEGV/SIGBUS we siglongjmp
89 * back.
90 * To be able to use this - don't take locks, don't rely on destructors,
91 * don't make OS library calls, don't allocate memory, don't print,
92 * don't call code that could leave the heap / memory in an inconsistent state,
93 * or anything else where we are not in control if we suddenly jump out.
94 */
95class WatcherThreadCrashProtection : public StackObj {
96public:
97  WatcherThreadCrashProtection();
98  bool call(os::CrashProtectionCallback& cb);
99
100  static void check_crash_protection(int signal, Thread* thread);
101private:
102  void restore();
103  sigjmp_buf _jmpbuf;
104};
105
106#endif // OS_POSIX_VM_OS_POSIX_HPP
107