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/* Copyright (C) 2003-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jakub@redhat.com>.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, see <https://www.gnu.org/licenses/>. */
#include <dlfcn.h>
#include <stdio.h>
#include <unwind.h>
#include <pthreadP.h>
#include <sysdep.h>
#include <gnu/lib-names.h>
#include <unwind-resume.h>
static void *libgcc_s_handle;
void (*__libgcc_s_resume) (struct _Unwind_Exception *exc)
attribute_hidden __attribute__ ((noreturn));
static _Unwind_Reason_Code (*libgcc_s_personality) PERSONALITY_PROTO;
static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
(struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
static _Unwind_Word (*libgcc_s_getcfa) (struct _Unwind_Context *);
void
__attribute_noinline__
pthread_cancel_init (void)
{
void *resume;
void *personality;
void *forcedunwind;
void *getcfa;
void *handle;
if (__glibc_likely (libgcc_s_handle != NULL))
{
/* Force gcc to reload all values. */
asm volatile ("" ::: "memory");
return;
}
/* See include/dlfcn.h. Use of __libc_dlopen requires RTLD_NOW. */
handle = __libc_dlopen (LIBGCC_S_SO);
if (handle == NULL
|| (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL
|| (personality = __libc_dlsym (handle, "__gcc_personality_v0")) == NULL
|| (forcedunwind = __libc_dlsym (handle, "_Unwind_ForcedUnwind"))
== NULL
|| (getcfa = __libc_dlsym (handle, "_Unwind_GetCFA")) == NULL
#ifdef ARCH_CANCEL_INIT
|| ARCH_CANCEL_INIT (handle)
#endif
)
__libc_fatal (LIBGCC_S_SO " must be installed for pthread_cancel to work\n");
PTR_MANGLE (resume);
__libgcc_s_resume = resume;
PTR_MANGLE (personality);
libgcc_s_personality = personality;
PTR_MANGLE (forcedunwind);
libgcc_s_forcedunwind = forcedunwind;
PTR_MANGLE (getcfa);
libgcc_s_getcfa = getcfa;
/* Make sure libgcc_s_handle is written last. Otherwise,
pthread_cancel_init might return early even when the pointer the
caller is interested in is not initialized yet. */
atomic_write_barrier ();
libgcc_s_handle = handle;
}
/* Register for cleanup in libpthread.so. */
void
__nptl_unwind_freeres (void)
{
void *handle = libgcc_s_handle;
if (handle != NULL)
{
libgcc_s_handle = NULL;
__libc_dlclose (handle);
}
}
#if !HAVE_ARCH_UNWIND_RESUME
void
_Unwind_Resume (struct _Unwind_Exception *exc)
{
if (__glibc_unlikely (libgcc_s_handle == NULL))
pthread_cancel_init ();
else
atomic_read_barrier ();
void (*resume) (struct _Unwind_Exception *exc) = __libgcc_s_resume;
PTR_DEMANGLE (resume);
resume (exc);
}
#endif
_Unwind_Reason_Code
__gcc_personality_v0 PERSONALITY_PROTO
{
if (__glibc_unlikely (libgcc_s_handle == NULL))
pthread_cancel_init ();
else
atomic_read_barrier ();
__typeof (libgcc_s_personality) personality = libgcc_s_personality;
PTR_DEMANGLE (personality);
return (*personality) PERSONALITY_ARGS;
}
_Unwind_Reason_Code
_Unwind_ForcedUnwind (struct _Unwind_Exception *exc, _Unwind_Stop_Fn stop,
void *stop_argument)
{
if (__glibc_unlikely (libgcc_s_handle == NULL))
pthread_cancel_init ();
else
atomic_read_barrier ();
_Unwind_Reason_Code (*forcedunwind)
(struct _Unwind_Exception *, _Unwind_Stop_Fn, void *)
= libgcc_s_forcedunwind;
PTR_DEMANGLE (forcedunwind);
return forcedunwind (exc, stop, stop_argument);
}
_Unwind_Word
_Unwind_GetCFA (struct _Unwind_Context *context)
{
if (__glibc_unlikely (libgcc_s_handle == NULL))
pthread_cancel_init ();
else
atomic_read_barrier ();
_Unwind_Word (*getcfa) (struct _Unwind_Context *) = libgcc_s_getcfa;
PTR_DEMANGLE (getcfa);
return getcfa (context);
}
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