| /* Return backtrace of current program state. 64 bit S/390 version. |
| Copyright (C) 2001-2018 Free Software Foundation, Inc. |
| Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>. |
| This file is part of the GNU C Library. |
| |
| 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 <stddef.h> |
| #include <stdlib.h> |
| #include <unwind.h> |
| |
| |
| /* This is a global variable set at program start time. It marks the |
| highest used stack address. */ |
| extern void *__libc_stack_end; |
| |
| |
| /* This is the stack layout we see for every non-leaf function. |
| size offset |
| %r15 -> +------------------+ |
| 8 | back chain | 0 |
| 8 | end of stack | 8 |
| 32 | scratch | 16 |
| 80 | save area r6-r15 | 48 |
| 16 | save area f4,f6 | 128 |
| 16 | empty | 144 |
| +------------------+ |
| r14 in the save area holds the return address. |
| */ |
| |
| struct layout |
| { |
| long back_chain; |
| long end_of_stack; |
| long scratch[4]; |
| long save_grps[10]; |
| long save_fp[2]; |
| long empty[2]; |
| }; |
| |
| struct trace_arg |
| { |
| void **array; |
| int cnt, size; |
| }; |
| |
| #ifdef SHARED |
| static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *); |
| static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *); |
| |
| static void |
| init (void) |
| { |
| void *handle = __libc_dlopen ("libgcc_s.so.1"); |
| |
| if (handle == NULL) |
| return; |
| |
| unwind_backtrace = __libc_dlsym (handle, "_Unwind_Backtrace"); |
| unwind_getip = __libc_dlsym (handle, "_Unwind_GetIP"); |
| if (unwind_getip == NULL) |
| unwind_backtrace = NULL; |
| } |
| |
| static int |
| __backchain_backtrace (void **array, int size) |
| { |
| /* We assume that all the code is generated with frame pointers set. */ |
| struct layout *stack; |
| int cnt = 0; |
| |
| __asm__ ("LGR %0,%%r15" : "=d" (stack) ); |
| /* We skip the call to this function, it makes no sense to record it. */ |
| stack = (struct layout *) stack->back_chain; |
| while (cnt < size) |
| { |
| if (stack == NULL || (void *) stack > __libc_stack_end) |
| /* This means the address is out of range. Note that for the |
| toplevel we see a frame pointer with value NULL which clearly is |
| out of range. */ |
| break; |
| |
| array[cnt++] = (void *) stack->save_grps[8]; |
| |
| stack = (struct layout *) stack->back_chain; |
| } |
| |
| return cnt; |
| } |
| #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 __backchain_backtrace (array, size); |
| #endif |
| |
| unwind_backtrace (backtrace_helper, &arg); |
| |
| return arg.cnt != -1 ? arg.cnt : 0; |
| } |
| |
| weak_alias (__backtrace, backtrace) |
| libc_hidden_def (__backtrace) |