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      1 /* Return list address ranges.
      2    Copyright (C) 2000-2010 Red Hat, Inc.
      3    This file is part of Red Hat elfutils.
      4    Written by Ulrich Drepper <drepper (at) redhat.com>, 2000.
      5 
      6    Red Hat elfutils is free software; you can redistribute it and/or modify
      7    it under the terms of the GNU General Public License as published by the
      8    Free Software Foundation; version 2 of the License.
      9 
     10    Red Hat elfutils is distributed in the hope that it will be useful, but
     11    WITHOUT ANY WARRANTY; without even the implied warranty of
     12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13    General Public License for more details.
     14 
     15    You should have received a copy of the GNU General Public License along
     16    with Red Hat elfutils; if not, write to the Free Software Foundation,
     17    Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
     18 
     19    In addition, as a special exception, Red Hat, Inc. gives You the
     20    additional right to link the code of Red Hat elfutils with code licensed
     21    under any Open Source Initiative certified open source license
     22    (http://www.opensource.org/licenses/index.php) which requires the
     23    distribution of source code with any binary distribution and to
     24    distribute linked combinations of the two.  Non-GPL Code permitted under
     25    this exception must only link to the code of Red Hat elfutils through
     26    those well defined interfaces identified in the file named EXCEPTION
     27    found in the source code files (the "Approved Interfaces").  The files
     28    of Non-GPL Code may instantiate templates or use macros or inline
     29    functions from the Approved Interfaces without causing the resulting
     30    work to be covered by the GNU General Public License.  Only Red Hat,
     31    Inc. may make changes or additions to the list of Approved Interfaces.
     32    Red Hat's grant of this exception is conditioned upon your not adding
     33    any new exceptions.  If you wish to add a new Approved Interface or
     34    exception, please contact Red Hat.  You must obey the GNU General Public
     35    License in all respects for all of the Red Hat elfutils code and other
     36    code used in conjunction with Red Hat elfutils except the Non-GPL Code
     37    covered by this exception.  If you modify this file, you may extend this
     38    exception to your version of the file, but you are not obligated to do
     39    so.  If you do not wish to provide this exception without modification,
     40    you must delete this exception statement from your version and license
     41    this file solely under the GPL without exception.
     42 
     43    Red Hat elfutils is an included package of the Open Invention Network.
     44    An included package of the Open Invention Network is a package for which
     45    Open Invention Network licensees cross-license their patents.  No patent
     46    license is granted, either expressly or impliedly, by designation as an
     47    included package.  Should you wish to participate in the Open Invention
     48    Network licensing program, please visit www.openinventionnetwork.com
     49    <http://www.openinventionnetwork.com>.  */
     50 
     51 #ifdef HAVE_CONFIG_H
     52 # include <config.h>
     53 #endif
     54 
     55 #include <stdlib.h>
     56 #include <assert.h>
     57 #include "libdwP.h"
     58 #include <dwarf.h>
     59 
     60 struct arangelist
     61 {
     62   Dwarf_Arange arange;
     63   struct arangelist *next;
     64 };
     65 
     66 /* Compare by Dwarf_Arange.addr, given pointers into an array of pointeers.  */
     67 static int
     68 compare_aranges (const void *a, const void *b)
     69 {
     70   struct arangelist *const *p1 = a, *const *p2 = b;
     71   struct arangelist *l1 = *p1, *l2 = *p2;
     72   return l1->arange.addr - l2->arange.addr;
     73 }
     74 
     75 int
     76 dwarf_getaranges (dbg, aranges, naranges)
     77      Dwarf *dbg;
     78      Dwarf_Aranges **aranges;
     79      size_t *naranges;
     80 {
     81   if (dbg == NULL)
     82     return -1;
     83 
     84   if (dbg->aranges != NULL)
     85     {
     86       *aranges = dbg->aranges;
     87       if (naranges != NULL)
     88 	*naranges = dbg->aranges->naranges;
     89       return 0;
     90     }
     91 
     92   if (dbg->sectiondata[IDX_debug_aranges] == NULL)
     93     {
     94       /* No such section.  */
     95       *aranges = NULL;
     96       if (naranges != NULL)
     97 	*naranges = 0;
     98       return 0;
     99     }
    100 
    101   if (dbg->sectiondata[IDX_debug_aranges]->d_buf == NULL)
    102     return -1;
    103 
    104   struct arangelist *arangelist = NULL;
    105   unsigned int narangelist = 0;
    106 
    107   const unsigned char *readp = dbg->sectiondata[IDX_debug_aranges]->d_buf;
    108   const unsigned char *readendp
    109     = readp + dbg->sectiondata[IDX_debug_aranges]->d_size;
    110 
    111   while (readp < readendp)
    112     {
    113       const unsigned char *hdrstart = readp;
    114 
    115       /* Each entry starts with a header:
    116 
    117 	 1. A 4-byte or 12-byte length containing the length of the
    118 	 set of entries for this compilation unit, not including the
    119 	 length field itself. [...]
    120 
    121 	 2. A 2-byte version identifier containing the value 2 for
    122 	 DWARF Version 2.1.
    123 
    124 	 3. A 4-byte or 8-byte offset into the .debug_info section. [...]
    125 
    126 	 4. A 1-byte unsigned integer containing the size in bytes of
    127 	 an address (or the offset portion of an address for segmented
    128 	 addressing) on the target system.
    129 
    130 	 5. A 1-byte unsigned integer containing the size in bytes of
    131 	 a segment descriptor on the target system.  */
    132       Dwarf_Word length = read_4ubyte_unaligned_inc (dbg, readp);
    133       unsigned int length_bytes = 4;
    134       if (length == DWARF3_LENGTH_64_BIT)
    135 	{
    136 	  length = read_8ubyte_unaligned_inc (dbg, readp);
    137 	  length_bytes = 8;
    138 	}
    139       else if (unlikely (length >= DWARF3_LENGTH_MIN_ESCAPE_CODE
    140 			 && length <= DWARF3_LENGTH_MAX_ESCAPE_CODE))
    141 	goto invalid;
    142 
    143       unsigned int version = read_2ubyte_unaligned_inc (dbg, readp);
    144       if (version != 2)
    145 	{
    146 	invalid:
    147 	  __libdw_seterrno (DWARF_E_INVALID_DWARF);
    148 	fail:
    149 	  while (arangelist != NULL)
    150 	    {
    151 	      struct arangelist *next = arangelist->next;
    152 	      free (arangelist);
    153 	      arangelist = next;
    154 	    }
    155 	  return -1;
    156 	}
    157 
    158       Dwarf_Word offset;
    159       if (__libdw_read_offset_inc (dbg,
    160 				   IDX_debug_aranges, &readp,
    161 				   length_bytes, &offset, IDX_debug_info, 4))
    162 	goto fail;
    163 
    164       unsigned int address_size = *readp++;
    165       if (address_size != 4 && address_size != 8)
    166 	goto invalid;
    167 
    168       /* Ignore the segment size value.  */
    169       // XXX Really?
    170       (void) *readp++;
    171 
    172       /* Round the address to the next multiple of 2*address_size.  */
    173       readp += ((2 * address_size - ((readp - hdrstart) % (2 * address_size)))
    174 		% (2 * address_size));
    175 
    176       while (1)
    177 	{
    178 	  Dwarf_Word range_address;
    179 	  Dwarf_Word range_length;
    180 
    181 	  if (__libdw_read_address_inc (dbg, IDX_debug_aranges, &readp,
    182 					address_size, &range_address))
    183 	    goto fail;
    184 
    185 	  if (address_size == 4)
    186 	    range_length = read_4ubyte_unaligned_inc (dbg, readp);
    187 	  else
    188 	    range_length = read_8ubyte_unaligned_inc (dbg, readp);
    189 
    190 	  /* Two zero values mark the end.  */
    191 	  if (range_address == 0 && range_length == 0)
    192 	    break;
    193 
    194 	  /* We don't use alloca for these temporary structures because
    195 	     the total number of them can be quite large.  */
    196 	  struct arangelist *new_arange = malloc (sizeof *new_arange);
    197 	  if (unlikely (new_arange == NULL))
    198 	    {
    199 	      __libdw_seterrno (DWARF_E_NOMEM);
    200 	      goto fail;
    201 	    }
    202 
    203 	  new_arange->arange.addr = range_address;
    204 	  new_arange->arange.length = range_length;
    205 
    206 	  /* We store the actual CU DIE offset, not the CU header offset.  */
    207 	  const char *cu_header = (dbg->sectiondata[IDX_debug_info]->d_buf
    208 				   + offset);
    209 	  unsigned int offset_size;
    210 	  if (read_4ubyte_unaligned_noncvt (cu_header) == DWARF3_LENGTH_64_BIT)
    211 	    offset_size = 8;
    212 	  else
    213 	    offset_size = 4;
    214 	  new_arange->arange.offset = DIE_OFFSET_FROM_CU_OFFSET (offset,
    215 								 offset_size,
    216 								 false);
    217 
    218 	  new_arange->next = arangelist;
    219 	  arangelist = new_arange;
    220 	  ++narangelist;
    221 
    222 	  /* Sanity-check the data.  */
    223 	  if (unlikely (new_arange->arange.offset
    224 			>= dbg->sectiondata[IDX_debug_info]->d_size))
    225 	    goto invalid;
    226 	}
    227     }
    228 
    229   if (narangelist == 0)
    230     {
    231       assert (arangelist == NULL);
    232       if (naranges != NULL)
    233 	*naranges = 0;
    234       *aranges = NULL;
    235       return 0;
    236     }
    237 
    238   /* Allocate the array for the result.  */
    239   void *buf = libdw_alloc (dbg, Dwarf_Aranges,
    240 			   sizeof (Dwarf_Aranges)
    241 			   + narangelist * sizeof (Dwarf_Arange), 1);
    242 
    243   /* First use the buffer for the pointers, and sort the entries.
    244      We'll write the pointers in the end of the buffer, and then
    245      copy into the buffer from the beginning so the overlap works.  */
    246   assert (sizeof (Dwarf_Arange) >= sizeof (Dwarf_Arange *));
    247   struct arangelist **sortaranges
    248     = (buf + sizeof (Dwarf_Aranges)
    249        + ((sizeof (Dwarf_Arange) - sizeof sortaranges[0]) * narangelist));
    250 
    251   /* The list is in LIFO order and usually they come in clumps with
    252      ascending addresses.  So fill from the back to probably start with
    253      runs already in order before we sort.  */
    254   unsigned int i = narangelist;
    255   while (i-- > 0)
    256     {
    257       sortaranges[i] = arangelist;
    258       arangelist = arangelist->next;
    259     }
    260   assert (arangelist == NULL);
    261 
    262   /* Sort by ascending address.  */
    263   qsort (sortaranges, narangelist, sizeof sortaranges[0], &compare_aranges);
    264 
    265   /* Now that they are sorted, put them in the final array.
    266      The buffers overlap, so we've clobbered the early elements
    267      of SORTARANGES by the time we're reading the later ones.  */
    268   *aranges = buf;
    269   (*aranges)->dbg = dbg;
    270   (*aranges)->naranges = narangelist;
    271   dbg->aranges = *aranges;
    272   if (naranges != NULL)
    273     *naranges = narangelist;
    274   for (i = 0; i < narangelist; ++i)
    275     {
    276       struct arangelist *elt = sortaranges[i];
    277       (*aranges)->info[i] = elt->arange;
    278       free (elt);
    279     }
    280 
    281   return 0;
    282 }
    283 INTDEF(dwarf_getaranges)
    284