1/* Return list address ranges.
2   Copyright (C) 2000, 2001, 2002, 2004, 2005, 2006, 2008 Red Hat, Inc.
3   This file is part of Red Hat elfutils.
4   Written by Ulrich Drepper <drepper@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
60struct 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.  */
67static int
68compare_aranges (const void *a, const void *b)
69{
70  Dwarf_Arange *const *p1 = a, *const *p2 = b;
71  Dwarf_Arange *l1 = *p1, *l2 = *p2;
72  return l1->addr - l2->addr;
73}
74
75int
76dwarf_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 char *readp
108    = (const char *) dbg->sectiondata[IDX_debug_aranges]->d_buf;
109  const char *readendp = readp + dbg->sectiondata[IDX_debug_aranges]->d_size;
110
111  while (readp < readendp)
112    {
113      const 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	  return -1;
149	}
150
151      Dwarf_Word offset;
152      if (length_bytes == 4)
153	offset = read_4ubyte_unaligned_inc (dbg, readp);
154      else
155	offset = read_8ubyte_unaligned_inc (dbg, readp);
156
157      /* Sanity-check the offset.  */
158      if (offset + 4 > dbg->sectiondata[IDX_debug_info]->d_size)
159	goto invalid;
160
161      unsigned int address_size = *readp++;
162      if (address_size != 4 && address_size != 8)
163	goto invalid;
164
165      /* Ignore the segment size value.  */
166      // XXX Really?
167      (void) *readp++;
168
169      /* Round the address to the next multiple of 2*address_size.  */
170      readp += ((2 * address_size - ((readp - hdrstart) % (2 * address_size)))
171		% (2 * address_size));
172
173      while (1)
174	{
175	  Dwarf_Word range_address;
176	  Dwarf_Word range_length;
177
178	  if (address_size == 4)
179	    {
180	      range_address = read_4ubyte_unaligned_inc (dbg, readp);
181	      range_length = read_4ubyte_unaligned_inc (dbg, readp);
182	    }
183	  else
184	    {
185	      range_address = read_8ubyte_unaligned_inc (dbg, readp);
186	      range_length = read_8ubyte_unaligned_inc (dbg, readp);
187	    }
188
189	  /* Two zero values mark the end.  */
190	  if (range_address == 0 && range_length == 0)
191	    break;
192
193	  struct arangelist *new_arange =
194	    (struct arangelist *) alloca (sizeof (struct arangelist));
195
196	  new_arange->arange.addr = range_address;
197	  new_arange->arange.length = range_length;
198
199	  /* We store the actual CU DIE offset, not the CU header offset.  */
200	  const char *cu_header = (dbg->sectiondata[IDX_debug_info]->d_buf
201				   + offset);
202	  unsigned int offset_size;
203	  if (read_4ubyte_unaligned_noncvt (cu_header) == DWARF3_LENGTH_64_BIT)
204	    offset_size = 8;
205	  else
206	    offset_size = 4;
207	  new_arange->arange.offset = DIE_OFFSET_FROM_CU_OFFSET (offset,
208								 offset_size);
209
210	  /* Sanity-check the data.  */
211	  if (new_arange->arange.offset
212	      >= dbg->sectiondata[IDX_debug_info]->d_size)
213	    goto invalid;
214
215	  new_arange->next = arangelist;
216	  arangelist = new_arange;
217	  ++narangelist;
218	}
219    }
220
221  if (narangelist == 0)
222    {
223      if (naranges != NULL)
224	*naranges = 0;
225      *aranges = NULL;
226      return 0;
227    }
228
229  /* Allocate the array for the result.  */
230  void *buf = libdw_alloc (dbg, Dwarf_Aranges,
231			   sizeof (Dwarf_Aranges)
232			   + narangelist * sizeof (Dwarf_Arange), 1);
233
234  /* First use the buffer for the pointers, and sort the entries.
235     We'll write the pointers in the end of the buffer, and then
236     copy into the buffer from the beginning so the overlap works.  */
237  assert (sizeof (Dwarf_Arange) >= sizeof (Dwarf_Arange *));
238  Dwarf_Arange **sortaranges = (buf + sizeof (Dwarf_Aranges)
239				+ ((sizeof (Dwarf_Arange)
240				    - sizeof (Dwarf_Arange *)) * narangelist));
241
242  /* The list is in LIFO order and usually they come in clumps with
243     ascending addresses.  So fill from the back to probably start with
244     runs already in order before we sort.  */
245  unsigned int i = narangelist;
246  while (i-- > 0)
247    {
248      sortaranges[i] = &arangelist->arange;
249      arangelist = arangelist->next;
250    }
251  assert (arangelist == NULL);
252
253  /* Sort by ascending address.  */
254  qsort (sortaranges, narangelist, sizeof sortaranges[0], &compare_aranges);
255
256  /* Now that they are sorted, put them in the final array.
257     The buffers overlap, so we've clobbered the early elements
258     of SORTARANGES by the time we're reading the later ones.  */
259  *aranges = buf;
260  (*aranges)->dbg = dbg;
261  (*aranges)->naranges = narangelist;
262  dbg->aranges = *aranges;
263  if (naranges != NULL)
264    *naranges = narangelist;
265  for (i = 0; i < narangelist; ++i)
266    (*aranges)->info[i] = *sortaranges[i];
267
268  return 0;
269}
270INTDEF(dwarf_getaranges)
271