libexec/ld.elf_so/arch/arm/find_exidx.c

   1 /*-
   2  * Copyright (c) 2013 The NetBSD Foundation, Inc.
   3  * All rights reserved.
   4  *
   5  * This code is derived from software contributed to The NetBSD Foundation
   6  * by Matt Thomas of 3am Software Foundry.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  19  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  20  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  21  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  27  * POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #include <sys/cdefs.h>
  31 #ifndef lint
  32 __RCSID("$NetBSD: find_exidx.c,v 1.4 2014/08/10 23:35:27 matt Exp $");
  33 #endif /* not lint */
  34
  35 #include "debug.h"
  36 #include "rtld.h"
  37
  38 #if defined(__ARM_EABI__) && !defined(__ARM_DWARF_EH__)
  39
  40 _Unwind_Ptr
  41 __gnu_Unwind_Find_exidx(_Unwind_Ptr pc, int * pcount)
  42 {
  43         const Obj_Entry *obj;
  44         _Unwind_Ptr start = NULL;
  45         int count = 0;
  46
  47         dbg(("__gnu_Unwind_Find_exidx"));
  48
  49         _rtld_shared_enter();
  50
  51         vaddr_t va = (vaddr_t)pc;
  52         for (obj = _rtld_objlist; obj != NULL; obj = obj->next) {
  53                 /*
  54                  * If the address we are looking for is inside this object,
  55                  * we've found the object to inspect.
  56                  */
  57                 if ((vaddr_t)obj->mapbase <= va
  58                     && va < (vaddr_t)obj->mapbase + obj->mapsize)
  59                         break;
  60         }
  61
  62         /*
  63          * If we found an object and it has some exception data, we
  64          * need to see if the address matches a PT_LOAD section.
  65          */
  66         if (obj != NULL && obj->exidx_start != NULL) {
  67                 va -= (vaddr_t)obj->relocbase;
  68                 const Elf_Phdr *ph = obj->phdr;
  69                 const Elf_Phdr * const phlimit = ph + obj->phsize / sizeof(*ph);
  70                 for (; ph < phlimit; ph++) {
  71                         if (ph->p_type == PT_LOAD
  72                             && ph->p_vaddr <= va
  73                             && va < ph->p_vaddr + ph->p_memsz) {
  74                                 count = obj->exidx_sz / 8;
  75                                 start = obj->exidx_start;
  76                                 break;
  77                         }
  78                 }
  79         }
  80
  81         _rtld_shared_exit();
  82
  83         /*
  84          * deal with the return values.
  85          */
  86         *pcount = count;
  87         return start;
  88 }
  89
  90 #endif