1/* Copyright (C) 2003-2017 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Jakub Jelinek <jakub@redhat.com>.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If
17 not, see <http://www.gnu.org/licenses/>. */
18
19#include <dlfcn.h>
20#include <stdio.h>
21#include <unwind.h>
22#include <pthreadP.h>
23#include <sysdep.h>
24#include <gnu/lib-names.h>
25#include <unwind-resume.h>
26
27static void *libgcc_s_handle;
28void (*__libgcc_s_resume) (struct _Unwind_Exception *exc)
29 attribute_hidden __attribute__ ((noreturn));
30static _Unwind_Reason_Code (*libgcc_s_personality) PERSONALITY_PROTO;
31static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
32 (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
33static _Unwind_Word (*libgcc_s_getcfa) (struct _Unwind_Context *);
34
35void
36__attribute_noinline__
37pthread_cancel_init (void)
38{
39 void *resume;
40 void *personality;
41 void *forcedunwind;
42 void *getcfa;
43 void *handle;
44
45 if (__glibc_likely (libgcc_s_handle != NULL))
46 {
47 /* Force gcc to reload all values. */
48 asm volatile ("" ::: "memory");
49 return;
50 }
51
52 handle = __libc_dlopen (LIBGCC_S_SO);
53
54 if (handle == NULL
55 || (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL
56 || (personality = __libc_dlsym (handle, "__gcc_personality_v0")) == NULL
57 || (forcedunwind = __libc_dlsym (handle, "_Unwind_ForcedUnwind"))
58 == NULL
59 || (getcfa = __libc_dlsym (handle, "_Unwind_GetCFA")) == NULL
60#ifdef ARCH_CANCEL_INIT
61 || ARCH_CANCEL_INIT (handle)
62#endif
63 )
64 __libc_fatal (LIBGCC_S_SO " must be installed for pthread_cancel to work\n");
65
66 PTR_MANGLE (resume);
67 __libgcc_s_resume = resume;
68 PTR_MANGLE (personality);
69 libgcc_s_personality = personality;
70 PTR_MANGLE (forcedunwind);
71 libgcc_s_forcedunwind = forcedunwind;
72 PTR_MANGLE (getcfa);
73 libgcc_s_getcfa = getcfa;
74 /* Make sure libgcc_s_handle is written last. Otherwise,
75 pthread_cancel_init might return early even when the pointer the
76 caller is interested in is not initialized yet. */
77 atomic_write_barrier ();
78 libgcc_s_handle = handle;
79}
80
81void
82__libc_freeres_fn_section
83__unwind_freeres (void)
84{
85 void *handle = libgcc_s_handle;
86 if (handle != NULL)
87 {
88 libgcc_s_handle = NULL;
89 __libc_dlclose (handle);
90 }
91}
92
93#if !HAVE_ARCH_UNWIND_RESUME
94void
95_Unwind_Resume (struct _Unwind_Exception *exc)
96{
97 if (__glibc_unlikely (libgcc_s_handle == NULL))
98 pthread_cancel_init ();
99 else
100 atomic_read_barrier ();
101
102 void (*resume) (struct _Unwind_Exception *exc) = __libgcc_s_resume;
103 PTR_DEMANGLE (resume);
104 resume (exc);
105}
106#endif
107
108_Unwind_Reason_Code
109__gcc_personality_v0 PERSONALITY_PROTO
110{
111 if (__glibc_unlikely (libgcc_s_handle == NULL))
112 pthread_cancel_init ();
113 else
114 atomic_read_barrier ();
115
116 __typeof (libgcc_s_personality) personality = libgcc_s_personality;
117 PTR_DEMANGLE (personality);
118 return (*personality) PERSONALITY_ARGS;
119}
120
121_Unwind_Reason_Code
122_Unwind_ForcedUnwind (struct _Unwind_Exception *exc, _Unwind_Stop_Fn stop,
123 void *stop_argument)
124{
125 if (__glibc_unlikely (libgcc_s_handle == NULL))
126 pthread_cancel_init ();
127 else
128 atomic_read_barrier ();
129
130 _Unwind_Reason_Code (*forcedunwind)
131 (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *)
132 = libgcc_s_forcedunwind;
133 PTR_DEMANGLE (forcedunwind);
134 return forcedunwind (exc, stop, stop_argument);
135}
136
137_Unwind_Word
138_Unwind_GetCFA (struct _Unwind_Context *context)
139{
140 if (__glibc_unlikely (libgcc_s_handle == NULL))
141 pthread_cancel_init ();
142 else
143 atomic_read_barrier ();
144
145 _Unwind_Word (*getcfa) (struct _Unwind_Context *) = libgcc_s_getcfa;
146 PTR_DEMANGLE (getcfa);
147 return getcfa (context);
148}
149