| /* Copyright (C) 2003-2018 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 <http://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> |
| #include <ldsodefs.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; |
| } |
| |
| handle = __libc_dlopen_mode (LIBGCC_S_SO, RTLD_NOW | __RTLD_DLOPEN); |
| |
| /* Google-local: b/5836136 */ |
| /* This is kind of weird to do, but has proven useful in cases where |
| the unwind support may be statically linked into us; we don't |
| want to pull in a redundant shared libgcc, we just want to use |
| the symbols we already have. */ |
| if (handle == NULL) |
| handle = GL(dl_ns)[LM_ID_BASE]._ns_loaded; |
| |
| 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; |
| } |
| |
| void |
| __libc_freeres_fn_section |
| __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); |
| } |