1/* Advance to next CU header. 2 Copyright (C) 2002-2010 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 Written by Ulrich Drepper <drepper@redhat.com>, 2002. 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 <libdwP.h> 56#include <dwarf.h> 57 58 59int 60dwarf_next_unit (dwarf, off, next_off, header_sizep, versionp, abbrev_offsetp, 61 address_sizep, offset_sizep, type_signaturep, type_offsetp) 62 Dwarf *dwarf; 63 Dwarf_Off off; 64 Dwarf_Off *next_off; 65 size_t *header_sizep; 66 Dwarf_Half *versionp; 67 Dwarf_Off *abbrev_offsetp; 68 uint8_t *address_sizep; 69 uint8_t *offset_sizep; 70 uint64_t *type_signaturep; 71 Dwarf_Off *type_offsetp; 72{ 73 const bool debug_types = type_signaturep != NULL; 74 const size_t sec_idx = debug_types ? IDX_debug_types : IDX_debug_info; 75 76 /* Maybe there has been an error before. */ 77 if (dwarf == NULL) 78 return -1; 79 80 /* If we reached the end before don't do anything. */ 81 if (off == (Dwarf_Off) -1l 82 || unlikely (dwarf->sectiondata[sec_idx] == NULL) 83 /* Make sure there is enough space in the .debug_info section 84 for at least the initial word. We cannot test the rest since 85 we don't know yet whether this is a 64-bit object or not. */ 86 || unlikely (off + 4 >= dwarf->sectiondata[sec_idx]->d_size)) 87 { 88 *next_off = (Dwarf_Off) -1l; 89 return 1; 90 } 91 92 /* This points into the .debug_info section to the beginning of the 93 CU entry. */ 94 const unsigned char *data = dwarf->sectiondata[sec_idx]->d_buf; 95 const unsigned char *bytes = data + off; 96 97 /* The format of the CU header is described in dwarf2p1 7.5.1: 98 99 1. A 4-byte or 12-byte unsigned integer representing the length 100 of the .debug_info contribution for that compilation unit, not 101 including the length field itself. In the 32-bit DWARF format, 102 this is a 4-byte unsigned integer (which must be less than 103 0xfffffff0); in the 64-bit DWARF format, this consists of the 104 4-byte value 0xffffffff followed by an 8-byte unsigned integer 105 that gives the actual length (see Section 7.2.2). 106 107 2. A 2-byte unsigned integer representing the version of the 108 DWARF information for that compilation unit. For DWARF Version 109 2.1, the value in this field is 2. 110 111 3. A 4-byte or 8-byte unsigned offset into the .debug_abbrev 112 section. This offset associates the compilation unit with a 113 particular set of debugging information entry abbreviations. In 114 the 32-bit DWARF format, this is a 4-byte unsigned length; in 115 the 64-bit DWARF format, this is an 8-byte unsigned length (see 116 Section 7.4). 117 118 4. A 1-byte unsigned integer representing the size in bytes of 119 an address on the target architecture. If the system uses 120 segmented addressing, this value represents the size of the 121 offset portion of an address. */ 122 uint64_t length = read_4ubyte_unaligned_inc (dwarf, bytes); 123 size_t offset_size = 4; 124 /* Lengths of 0xfffffff0 - 0xffffffff are escape codes. Oxffffffff is 125 used to indicate that 64-bit dwarf information is being used, the 126 other values are currently reserved. */ 127 if (length == DWARF3_LENGTH_64_BIT) 128 offset_size = 8; 129 else if (unlikely (length >= DWARF3_LENGTH_MIN_ESCAPE_CODE 130 && length <= DWARF3_LENGTH_MAX_ESCAPE_CODE)) 131 { 132 invalid: 133 __libdw_seterrno (DWARF_E_INVALID_DWARF); 134 return -1; 135 } 136 137 /* Now we know how large the header is. */ 138 if (unlikely (DIE_OFFSET_FROM_CU_OFFSET (off, offset_size, debug_types) 139 >= dwarf->sectiondata[sec_idx]->d_size)) 140 { 141 *next_off = -1; 142 return 1; 143 } 144 145 if (length == DWARF3_LENGTH_64_BIT) 146 /* This is a 64-bit DWARF format. */ 147 length = read_8ubyte_unaligned_inc (dwarf, bytes); 148 149 /* Read the version stamp. Always a 16-bit value. */ 150 uint_fast16_t version = read_2ubyte_unaligned_inc (dwarf, bytes); 151 152 /* Get offset in .debug_abbrev. Note that the size of the entry 153 depends on whether this is a 32-bit or 64-bit DWARF definition. */ 154 uint64_t abbrev_offset; 155 if (__libdw_read_offset_inc (dwarf, sec_idx, &bytes, offset_size, 156 &abbrev_offset, IDX_debug_abbrev, 0)) 157 return -1; 158 159 /* The address size. Always an 8-bit value. */ 160 uint8_t address_size = *bytes++; 161 162 if (debug_types) 163 { 164 uint64_t type_sig8 = read_8ubyte_unaligned_inc (dwarf, bytes); 165 166 Dwarf_Off type_offset; 167 if (__libdw_read_offset_inc (dwarf, sec_idx, &bytes, offset_size, 168 &type_offset, sec_idx, 0)) 169 return -1; 170 171 /* Validate that the TYPE_OFFSET points past the header. */ 172 if (unlikely (type_offset < (size_t) (bytes - (data + off)))) 173 goto invalid; 174 175 *type_signaturep = type_sig8; 176 if (type_offsetp != NULL) 177 *type_offsetp = type_offset; 178 } 179 180 /* Store the header length. */ 181 if (header_sizep != NULL) 182 *header_sizep = bytes - (data + off); 183 184 if (versionp != NULL) 185 *versionp = version; 186 187 if (abbrev_offsetp != NULL) 188 *abbrev_offsetp = abbrev_offset; 189 190 if (address_sizep != NULL) 191 *address_sizep = address_size; 192 193 /* Store the offset size. */ 194 if (offset_sizep != NULL) 195 *offset_sizep = offset_size; 196 197 /* See definition of DIE_OFFSET_FROM_CU_OFFSET macro 198 for an explanation of the trick in this expression. */ 199 *next_off = off + 2 * offset_size - 4 + length; 200 201 return 0; 202} 203INTDEF(dwarf_next_unit) 204 205int 206dwarf_nextcu (dwarf, off, next_off, header_sizep, abbrev_offsetp, 207 address_sizep, offset_sizep) 208 Dwarf *dwarf; 209 Dwarf_Off off; 210 Dwarf_Off *next_off; 211 size_t *header_sizep; 212 Dwarf_Off *abbrev_offsetp; 213 uint8_t *address_sizep; 214 uint8_t *offset_sizep; 215{ 216 return INTUSE(dwarf_next_unit) (dwarf, off, next_off, header_sizep, NULL, 217 abbrev_offsetp, address_sizep, offset_sizep, 218 NULL, NULL); 219} 220INTDEF(dwarf_nextcu) 221