| /* Return backtrace of current program state. |
| Copyright (C) 2008-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Kazu Hirata <kazu@codesourcery.com>, 2008. |
| |
| 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. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <libc-lock.h> |
| #include <dlfcn.h> |
| #include <execinfo.h> |
| #include <stdlib.h> |
| #include <unwind.h> |
| |
| struct trace_arg |
| { |
| void **array; |
| int cnt, size; |
| }; |
| |
| #ifdef SHARED |
| static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *); |
| static _Unwind_VRS_Result (*unwind_vrs_get) (_Unwind_Context *, |
| _Unwind_VRS_RegClass, |
| _uw, |
| _Unwind_VRS_DataRepresentation, |
| void *); |
| |
| static void *libgcc_handle; |
| |
| static void |
| init (void) |
| { |
| libgcc_handle = __libc_dlopen ("libgcc_s.so.1"); |
| |
| if (libgcc_handle == NULL) |
| return; |
| |
| unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace"); |
| unwind_vrs_get = __libc_dlsym (libgcc_handle, "_Unwind_VRS_Get"); |
| if (unwind_vrs_get == NULL) |
| unwind_backtrace = NULL; |
| } |
| |
| /* This function is identical to "_Unwind_GetGR", except that it uses |
| "unwind_vrs_get" instead of "_Unwind_VRS_Get". */ |
| static inline _Unwind_Word |
| unwind_getgr (_Unwind_Context *context, int regno) |
| { |
| _uw val; |
| unwind_vrs_get (context, _UVRSC_CORE, regno, _UVRSD_UINT32, &val); |
| return val; |
| } |
| |
| /* This macro is identical to the _Unwind_GetIP macro, except that it |
| uses "unwind_getgr" instead of "_Unwind_GetGR". */ |
| # define unwind_getip(context) \ |
| (unwind_getgr (context, 15) & ~(_Unwind_Word)1) |
| #else |
| # define unwind_backtrace _Unwind_Backtrace |
| # define unwind_getip _Unwind_GetIP |
| #endif |
| |
| static _Unwind_Reason_Code |
| backtrace_helper (struct _Unwind_Context *ctx, void *a) |
| { |
| struct trace_arg *arg = a; |
| |
| /* We are first called with address in the __backtrace function. |
| Skip it. */ |
| if (arg->cnt != -1) |
| arg->array[arg->cnt] = (void *) unwind_getip (ctx); |
| if (++arg->cnt == arg->size) |
| return _URC_END_OF_STACK; |
| return _URC_NO_REASON; |
| } |
| |
| int |
| __backtrace (void **array, int size) |
| { |
| struct trace_arg arg = { .array = array, .size = size, .cnt = -1 }; |
| |
| if (size <= 0) |
| return 0; |
| |
| #ifdef SHARED |
| __libc_once_define (static, once); |
| |
| __libc_once (once, init); |
| if (unwind_backtrace == NULL) |
| return 0; |
| #endif |
| |
| unwind_backtrace (backtrace_helper, &arg); |
| |
| if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL) |
| --arg.cnt; |
| return arg.cnt != -1 ? arg.cnt : 0; |
| } |
| weak_alias (__backtrace, backtrace) |
| libc_hidden_def (__backtrace) |
| |
| |
| #ifdef SHARED |
| /* Free all resources if necessary. */ |
| libc_freeres_fn (free_mem) |
| { |
| unwind_backtrace = NULL; |
| if (libgcc_handle != NULL) |
| { |
| __libc_dlclose (libgcc_handle); |
| libgcc_handle = NULL; |
| } |
| } |
| #endif |