1/* Find CU for given offset.
2   Copyright (C) 2003-2010, 2014 Red Hat, Inc.
3   This file is part of elfutils.
4   Written by Ulrich Drepper <drepper@redhat.com>, 2003.
5
6   This file is free software; you can redistribute it and/or modify
7   it under the terms of either
8
9     * the GNU Lesser General Public License as published by the Free
10       Software Foundation; either version 3 of the License, or (at
11       your option) any later version
12
13   or
14
15     * the GNU General Public License as published by the Free
16       Software Foundation; either version 2 of the License, or (at
17       your option) any later version
18
19   or both in parallel, as here.
20
21   elfutils is distributed in the hope that it will be useful, but
22   WITHOUT ANY WARRANTY; without even the implied warranty of
23   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
24   General Public License for more details.
25
26   You should have received copies of the GNU General Public License and
27   the GNU Lesser General Public License along with this program.  If
28   not, see <http://www.gnu.org/licenses/>.  */
29
30#ifdef HAVE_CONFIG_H
31# include <config.h>
32#endif
33
34#include <assert.h>
35#include <search.h>
36#include "libdwP.h"
37
38static int
39findcu_cb (const void *arg1, const void *arg2)
40{
41  struct Dwarf_CU *cu1 = (struct Dwarf_CU *) arg1;
42  struct Dwarf_CU *cu2 = (struct Dwarf_CU *) arg2;
43
44  /* Find out which of the two arguments is the search value.  It has
45     end offset 0.  */
46  if (cu1->end == 0)
47    {
48      if (cu1->start < cu2->start)
49	return -1;
50      if (cu1->start >= cu2->end)
51	return 1;
52    }
53  else
54    {
55      if (cu2->start < cu1->start)
56	return 1;
57      if (cu2->start >= cu1->end)
58	return -1;
59    }
60
61  return 0;
62}
63
64struct Dwarf_CU *
65internal_function
66__libdw_intern_next_unit (Dwarf *dbg, bool debug_types)
67{
68  Dwarf_Off *const offsetp
69    = debug_types ? &dbg->next_tu_offset : &dbg->next_cu_offset;
70  void **tree = debug_types ? &dbg->tu_tree : &dbg->cu_tree;
71
72  Dwarf_Off oldoff = *offsetp;
73  uint16_t version;
74  uint8_t address_size;
75  uint8_t offset_size;
76  Dwarf_Off abbrev_offset;
77  uint64_t type_sig8 = 0;
78  Dwarf_Off type_offset = 0;
79
80  if (INTUSE(dwarf_next_unit) (dbg, oldoff, offsetp, NULL,
81			       &version, &abbrev_offset,
82			       &address_size, &offset_size,
83			       debug_types ? &type_sig8 : NULL,
84			       debug_types ? &type_offset : NULL) != 0)
85    /* No more entries.  */
86    return NULL;
87
88  /* We only know how to handle the DWARF version 2 through 4 formats.  */
89  if (unlikely (version < 2) || unlikely (version > 4))
90    {
91      __libdw_seterrno (DWARF_E_INVALID_DWARF);
92      return NULL;
93    }
94
95  /* Invalid or truncated debug section data?  */
96  Elf_Data *data = dbg->sectiondata[debug_types
97				    ? IDX_debug_types : IDX_debug_info];
98  if (unlikely (*offsetp > data->d_size))
99    *offsetp = data->d_size;
100
101  /* Create an entry for this CU.  */
102  struct Dwarf_CU *newp = libdw_typed_alloc (dbg, struct Dwarf_CU);
103
104  newp->dbg = dbg;
105  newp->start = oldoff;
106  newp->end = *offsetp;
107  newp->address_size = address_size;
108  newp->offset_size = offset_size;
109  newp->version = version;
110  newp->type_sig8 = type_sig8;
111  newp->type_offset = type_offset;
112  Dwarf_Abbrev_Hash_init (&newp->abbrev_hash, 41);
113  newp->orig_abbrev_offset = newp->last_abbrev_offset = abbrev_offset;
114  newp->lines = NULL;
115  newp->locs = NULL;
116
117  if (debug_types)
118    Dwarf_Sig8_Hash_insert (&dbg->sig8_hash, type_sig8, newp);
119
120  newp->startp = data->d_buf + newp->start;
121  newp->endp = data->d_buf + newp->end;
122
123  /* Add the new entry to the search tree.  */
124  if (tsearch (newp, tree, findcu_cb) == NULL)
125    {
126      /* Something went wrong.  Undo the operation.  */
127      *offsetp = oldoff;
128      __libdw_seterrno (DWARF_E_NOMEM);
129      return NULL;
130    }
131
132  return newp;
133}
134
135struct Dwarf_CU *
136internal_function
137__libdw_findcu (Dwarf *dbg, Dwarf_Off start, bool debug_types)
138{
139  void **tree = debug_types ? &dbg->tu_tree : &dbg->cu_tree;
140  Dwarf_Off *next_offset
141    = debug_types ? &dbg->next_tu_offset : &dbg->next_cu_offset;
142
143  /* Maybe we already know that CU.  */
144  struct Dwarf_CU fake = { .start = start, .end = 0 };
145  struct Dwarf_CU **found = tfind (&fake, tree, findcu_cb);
146  if (found != NULL)
147    return *found;
148
149  if (start < *next_offset)
150    {
151      __libdw_seterrno (DWARF_E_INVALID_DWARF);
152      return NULL;
153    }
154
155  /* No.  Then read more CUs.  */
156  while (1)
157    {
158      struct Dwarf_CU *newp = __libdw_intern_next_unit (dbg, debug_types);
159      if (newp == NULL)
160	return NULL;
161
162      /* Is this the one we are looking for?  */
163      if (start < *next_offset)
164	// XXX Match exact offset.
165	return newp;
166    }
167  /* NOTREACHED */
168}
169