1 /*
2 * Copyright (c) 1999, 2016, 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
31 static const char* file_separator() { return "/"; }
32 static const char* line_separator() { return "\n"; }
33 static const char* path_separator() { return ":"; }
34
35 class Posix {
36 friend class os;
37
38 protected:
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
45 // Minimum stack size a thread can be created with (allowing
46 // the VM to completely create the thread and enter user code).
47 // The initial values exclude any guard pages (by HotSpot or libc).
48 // set_minimum_stack_sizes() will add the size required for
49 // HotSpot guard pages depending on page size and flag settings.
50 // Libc guard pages are never considered by these values.
51 static size_t _compiler_thread_min_stack_allowed;
52 static size_t _java_thread_min_stack_allowed;
53 static size_t _vm_internal_thread_min_stack_allowed;
54
55 public:
56 // Return default stack size for the specified thread type
57 static size_t default_stack_size(os::ThreadType thr_type);
58 // Check and sets minimum stack sizes
59 static jint set_minimum_stack_sizes();
60 static size_t get_initial_stack_size(ThreadType thr_type, size_t req_stack_size);
61
62 // Returns true if signal is valid.
63 static bool is_valid_signal(int sig);
64
65 // Helper function, returns a string (e.g. "SIGILL") for a signal.
66 // Returned string is a constant. For unknown signals "UNKNOWN" is returned.
67 static const char* get_signal_name(int sig, char* out, size_t outlen);
68
69 // Helper function, returns a signal number for a given signal name, e.g. 11
70 // for "SIGSEGV". Name can be given with or without "SIG" prefix, so both
71 // "SEGV" or "SIGSEGV" work. Name must be uppercase.
72 // Returns -1 for an unknown signal name.
73 static int get_signal_number(const char* signal_name);
74
75 // Returns one-line short description of a signal set in a user provided buffer.
76 static const char* describe_signal_set_short(const sigset_t* set, char* buffer, size_t size);
77
78 // Prints a short one-line description of a signal set.
79 static void print_signal_set_short(outputStream* st, const sigset_t* set);
80
81 // unblocks the signal masks for current thread
82 static int unblock_thread_signal_mask(const sigset_t *set);
83
84 // Writes a one-line description of a combination of sigaction.sa_flags
85 // into a user provided buffer. Returns that buffer.
86 static const char* describe_sa_flags(int flags, char* buffer, size_t size);
87
88 // Prints a one-line description of a combination of sigaction.sa_flags.
89 static void print_sa_flags(outputStream* st, int flags);
90
91 static address ucontext_get_pc(const ucontext_t* ctx);
92 // Set PC into context. Needed for continuation after signal.
93 static void ucontext_set_pc(ucontext_t* ctx, address pc);
94
95 // Helper function; describes pthread attributes as short string. String is written
96 // to buf with len buflen; buf is returned.
97 static char* describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr);
98
99 };
100
101 /*
102 * Crash protection for the watcher thread. Wrap the callback
103 * with a sigsetjmp and in case of a SIGSEGV/SIGBUS we siglongjmp
104 * back.
105 * To be able to use this - don't take locks, don't rely on destructors,
106 * don't make OS library calls, don't allocate memory, don't print,
107 * don't call code that could leave the heap / memory in an inconsistent state,
108 * or anything else where we are not in control if we suddenly jump out.
109 */
110 class WatcherThreadCrashProtection : public StackObj {
111 public:
112 WatcherThreadCrashProtection();
113 bool call(os::CrashProtectionCallback& cb);
114
115 static void check_crash_protection(int signal, Thread* thread);
116 private:
117 void restore();
118 sigjmp_buf _jmpbuf;
119 };
120
121 #endif // OS_POSIX_VM_OS_POSIX_HPP