1  /* Copyright (C) 2005-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library.  If not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <link.h>
      19  #include <unwind.h>
      20  
      21  struct unw_eh_callback_data
      22  {
      23    _Unwind_Ptr pc;
      24    _Unwind_Ptr exidx_start;
      25    int exidx_len;
      26  };
      27  
      28  
      29  /* Callback to determines if the PC lies within an object, and remember the
      30     location of the exception index table if it does.  */
      31  
      32  static int
      33  find_exidx_callback (struct dl_phdr_info * info, size_t size, void * ptr)
      34  {
      35    struct unw_eh_callback_data * data;
      36    const ElfW(Phdr) *phdr;
      37    int i;
      38    int match;
      39    _Unwind_Ptr load_base;
      40  
      41    data = (struct unw_eh_callback_data *) ptr;
      42    load_base = info->dlpi_addr;
      43    phdr = info->dlpi_phdr;
      44  
      45    match = 0;
      46    for (i = info->dlpi_phnum; i > 0; i--, phdr++)
      47      {
      48        if (phdr->p_type == PT_LOAD)
      49          {
      50            _Unwind_Ptr vaddr = phdr->p_vaddr + load_base;
      51            if (data->pc >= vaddr && data->pc < vaddr + phdr->p_memsz)
      52              match = 1;
      53          }
      54        else if (phdr->p_type == PT_ARM_EXIDX)
      55  	{
      56  	  data->exidx_start = (_Unwind_Ptr) (phdr->p_vaddr + load_base);
      57  	  data->exidx_len = phdr->p_memsz;
      58  	}
      59      }
      60  
      61    return match;
      62  }
      63  
      64  
      65  /* Find the exception index table containing PC.  */
      66  
      67  _Unwind_Ptr
      68  __gnu_Unwind_Find_exidx (_Unwind_Ptr pc, int * pcount)
      69  {
      70    struct unw_eh_callback_data data;
      71  
      72    data.pc = pc;
      73    data.exidx_start = 0;
      74    if (__dl_iterate_phdr (find_exidx_callback, &data) <= 0)
      75      return 0;
      76  
      77    *pcount = data.exidx_len / 8;
      78    return data.exidx_start;
      79  }