sysdeps/ia64/backtrace.c

   1 /* Return backtrace of current program state.
   2    Copyright (C) 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <bits/libc-lock.h>
  22 #include <dlfcn.h>
  23 #include <execinfo.h>
  24 #include <stdlib.h>
  25 #include <unwind.h>
  26
  27 struct trace_arg
  28 {
  29   void **array;
  30   int cnt, size;
  31 };
  32
  33 #ifdef SHARED
  34 static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
  35 static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);
  36 static void *libgcc_handle;
  37
  38 static void
  39 init (void)
  40 {
  41   libgcc_handle = __libc_dlopen ("libgcc_s.so.1");
  42
  43   if (libgcc_handle == NULL)
  44     return;
  45
  46   unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace");
  47   unwind_getip = __libc_dlsym (libgcc_handle, "_Unwind_GetIP");
  48   if (unwind_getip == NULL)
  49     unwind_backtrace = NULL;
  50 }
  51 #else
  52 # define unwind_backtrace _Unwind_Backtrace
  53 # define unwind_getip _Unwind_GetIP
  54 #endif
  55
  56 static _Unwind_Reason_Code
  57 backtrace_helper (struct _Unwind_Context *ctx, void *a)
  58 {
  59   struct trace_arg *arg = a;
  60
  61   /* We are first called with address in the __backtrace function.
  62      Skip it.  */
  63   if (arg->cnt != -1)
  64     arg->array[arg->cnt] = (void *) unwind_getip (ctx);
  65   if (++arg->cnt == arg->size)
  66     return _URC_END_OF_STACK;
  67   return _URC_NO_REASON;
  68 }
  69
  70 int
  71 __backtrace (array, size)
  72      void **array;
  73      int size;
  74 {
  75   struct trace_arg arg = { .array = array, .size = size, .cnt = -1 };
  76 #ifdef SHARED
  77   __libc_once_define (static, once);
  78
  79   __libc_once (once, init);
  80   if (unwind_backtrace == NULL)
  81     return 0;
  82 #endif
  83
  84   if (size >= 1)
  85     unwind_backtrace (backtrace_helper, &arg);
  86
  87   /* _Unwind_Backtrace on IA-64 seems to put NULL address above
  88      _start.  Fix it up here.  */
  89   if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
  90     --arg.cnt;
  91   return arg.cnt != -1 ? arg.cnt : 0;
  92 }
  93 weak_alias (__backtrace, backtrace)
  94 libc_hidden_def (__backtrace)
  95
  96
  97 #ifdef SHARED
  98 /* Free all resources if necessary.  */
  99 libc_freeres_fn (free_mem)
 100 {
 101   unwind_backtrace = NULL;
 102   if (libgcc_handle != NULL)
 103     {
 104       __libc_dlclose (libgcc_handle);
 105       libgcc_handle = NULL;
 106     }
 107 }
 108 #endif