Branch data Line data Source code
1 : : /* Advance to next CU header.
2 : : Copyright (C) 2002-2010 Red Hat, Inc.
3 : : This file is part of elfutils.
4 : : Written by Ulrich Drepper <drepper@redhat.com>, 2002.
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 <libdwP.h>
35 : : #include <dwarf.h>
36 : :
37 : :
38 : : int
39 : 109921 : dwarf_next_unit (dwarf, off, next_off, header_sizep, versionp, abbrev_offsetp,
40 : : address_sizep, offset_sizep, type_signaturep, type_offsetp)
41 : : Dwarf *dwarf;
42 : : Dwarf_Off off;
43 : : Dwarf_Off *next_off;
44 : : size_t *header_sizep;
45 : : Dwarf_Half *versionp;
46 : : Dwarf_Off *abbrev_offsetp;
47 : : uint8_t *address_sizep;
48 : : uint8_t *offset_sizep;
49 : : uint64_t *type_signaturep;
50 : : Dwarf_Off *type_offsetp;
51 : : {
52 : 109921 : const bool debug_types = type_signaturep != NULL;
53 : 109921 : const size_t sec_idx = debug_types ? IDX_debug_types : IDX_debug_info;
54 : :
55 : : /* Maybe there has been an error before. */
56 [ + - ]: 109921 : if (dwarf == NULL)
57 : : return -1;
58 : :
59 : : /* If we reached the end before don't do anything. */
60 [ + - ]: 109921 : if (off == (Dwarf_Off) -1l
61 [ + - ]: 109921 : || unlikely (dwarf->sectiondata[sec_idx] == NULL)
62 : : /* Make sure there is enough space in the .debug_info section
63 : : for at least the initial word. We cannot test the rest since
64 : : we don't know yet whether this is a 64-bit object or not. */
65 [ + + ]: 109921 : || unlikely (off + 4 >= dwarf->sectiondata[sec_idx]->d_size))
66 : : {
67 : 380 : *next_off = (Dwarf_Off) -1l;
68 : : return 1;
69 : : }
70 : :
71 : : /* This points into the .debug_info section to the beginning of the
72 : : CU entry. */
73 : 109541 : const unsigned char *data = dwarf->sectiondata[sec_idx]->d_buf;
74 : 109541 : const unsigned char *bytes = data + off;
75 : :
76 : : /* The format of the CU header is described in dwarf2p1 7.5.1:
77 : :
78 : : 1. A 4-byte or 12-byte unsigned integer representing the length
79 : : of the .debug_info contribution for that compilation unit, not
80 : : including the length field itself. In the 32-bit DWARF format,
81 : : this is a 4-byte unsigned integer (which must be less than
82 : : 0xfffffff0); in the 64-bit DWARF format, this consists of the
83 : : 4-byte value 0xffffffff followed by an 8-byte unsigned integer
84 : : that gives the actual length (see Section 7.2.2).
85 : :
86 : : 2. A 2-byte unsigned integer representing the version of the
87 : : DWARF information for that compilation unit. For DWARF Version
88 : : 2.1, the value in this field is 2.
89 : :
90 : : 3. A 4-byte or 8-byte unsigned offset into the .debug_abbrev
91 : : section. This offset associates the compilation unit with a
92 : : particular set of debugging information entry abbreviations. In
93 : : the 32-bit DWARF format, this is a 4-byte unsigned length; in
94 : : the 64-bit DWARF format, this is an 8-byte unsigned length (see
95 : : Section 7.4).
96 : :
97 : : 4. A 1-byte unsigned integer representing the size in bytes of
98 : : an address on the target architecture. If the system uses
99 : : segmented addressing, this value represents the size of the
100 : : offset portion of an address. */
101 [ + + ][ - + ]: 109541 : uint64_t length = read_4ubyte_unaligned_inc (dwarf, bytes);
102 : 109541 : size_t offset_size = 4;
103 : : /* Lengths of 0xfffffff0 - 0xffffffff are escape codes. Oxffffffff is
104 : : used to indicate that 64-bit dwarf information is being used, the
105 : : other values are currently reserved. */
106 [ + - ]: 109541 : if (length == DWARF3_LENGTH_64_BIT)
107 : : offset_size = 8;
108 [ - + ]: 109541 : else if (unlikely (length >= DWARF3_LENGTH_MIN_ESCAPE_CODE
109 : : && length <= DWARF3_LENGTH_MAX_ESCAPE_CODE))
110 : : {
111 : : invalid:
112 : 0 : __libdw_seterrno (DWARF_E_INVALID_DWARF);
113 : : return -1;
114 : : }
115 : :
116 : : /* Now we know how large the header is. */
117 [ + + ][ - + ]: 109541 : if (unlikely (DIE_OFFSET_FROM_CU_OFFSET (off, offset_size, debug_types)
118 : : >= dwarf->sectiondata[sec_idx]->d_size))
119 : : {
120 : 0 : *next_off = -1;
121 : : return 1;
122 : : }
123 : :
124 [ - + ]: 109541 : if (length == DWARF3_LENGTH_64_BIT)
125 : : /* This is a 64-bit DWARF format. */
126 [ # # ][ # # ]: 0 : length = read_8ubyte_unaligned_inc (dwarf, bytes);
127 : :
128 : : /* Read the version stamp. Always a 16-bit value. */
129 [ + + ][ - + ]: 109541 : uint_fast16_t version = read_2ubyte_unaligned_inc (dwarf, bytes);
130 : :
131 : : /* Get offset in .debug_abbrev. Note that the size of the entry
132 : : depends on whether this is a 32-bit or 64-bit DWARF definition. */
133 : : uint64_t abbrev_offset;
134 [ + - ]: 109541 : if (__libdw_read_offset_inc (dwarf, sec_idx, &bytes, offset_size,
135 : : &abbrev_offset, IDX_debug_abbrev, 0))
136 : : return -1;
137 : :
138 : : /* The address size. Always an 8-bit value. */
139 : 109541 : uint8_t address_size = *bytes++;
140 : :
141 [ + + ]: 109541 : if (debug_types)
142 : : {
143 [ - + ][ # # ]: 2 : uint64_t type_sig8 = read_8ubyte_unaligned_inc (dwarf, bytes);
144 : :
145 : : Dwarf_Off type_offset;
146 [ - + ]: 2 : if (__libdw_read_offset_inc (dwarf, sec_idx, &bytes, offset_size,
147 : : &type_offset, sec_idx, 0))
148 : : return -1;
149 : :
150 : : /* Validate that the TYPE_OFFSET points past the header. */
151 [ + - ]: 2 : if (unlikely (type_offset < (size_t) (bytes - (data + off))))
152 : : goto invalid;
153 : :
154 : 2 : *type_signaturep = type_sig8;
155 [ + + ]: 2 : if (type_offsetp != NULL)
156 : 2 : *type_offsetp = type_offset;
157 : : }
158 : :
159 : : /* Store the header length. */
160 [ + + ]: 109541 : if (header_sizep != NULL)
161 : 90389 : *header_sizep = bytes - (data + off);
162 : :
163 [ + + ]: 109541 : if (versionp != NULL)
164 : 20497 : *versionp = version;
165 : :
166 [ + + ]: 109541 : if (abbrev_offsetp != NULL)
167 : 20515 : *abbrev_offsetp = abbrev_offset;
168 : :
169 [ + + ]: 109541 : if (address_sizep != NULL)
170 : 20515 : *address_sizep = address_size;
171 : :
172 : : /* Store the offset size. */
173 [ + + ]: 109541 : if (offset_sizep != NULL)
174 : 20515 : *offset_sizep = offset_size;
175 : :
176 : : /* See definition of DIE_OFFSET_FROM_CU_OFFSET macro
177 : : for an explanation of the trick in this expression. */
178 : 109921 : *next_off = off + 2 * offset_size - 4 + length;
179 : :
180 : : return 0;
181 : : }
182 : : INTDEF(dwarf_next_unit)
183 : :
184 : : int
185 : 89380 : dwarf_nextcu (dwarf, off, next_off, header_sizep, abbrev_offsetp,
186 : : address_sizep, offset_sizep)
187 : : Dwarf *dwarf;
188 : : Dwarf_Off off;
189 : : Dwarf_Off *next_off;
190 : : size_t *header_sizep;
191 : : Dwarf_Off *abbrev_offsetp;
192 : : uint8_t *address_sizep;
193 : : uint8_t *offset_sizep;
194 : : {
195 : 89380 : return INTUSE(dwarf_next_unit) (dwarf, off, next_off, header_sizep, NULL,
196 : : abbrev_offsetp, address_sizep, offset_sizep,
197 : : NULL, NULL);
198 : : }
199 : : INTDEF(dwarf_nextcu)
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