1 /* Advance to next CU header. 2 Copyright (C) 2002, 2003, 2004, 2005, 2008 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 Written by Ulrich Drepper <drepper (at) 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 59 int 60 dwarf_nextcu (dwarf, off, next_off, header_sizep, abbrev_offsetp, 61 address_sizep, offset_sizep) 62 Dwarf *dwarf; 63 Dwarf_Off off; 64 Dwarf_Off *next_off; 65 size_t *header_sizep; 66 Dwarf_Off *abbrev_offsetp; 67 uint8_t *address_sizep; 68 uint8_t *offset_sizep; 69 { 70 /* Maybe there has been an error before. */ 71 if (dwarf == NULL) 72 return -1; 73 74 /* If we reached the end before don't do anything. */ 75 if (off == (Dwarf_Off) -1l 76 /* Make sure there is enough space in the .debug_info section 77 for at least the initial word. We cannot test the rest since 78 we don't know yet whether this is a 64-bit object or not. */ 79 || unlikely (off + 4 >= dwarf->sectiondata[IDX_debug_info]->d_size)) 80 { 81 *next_off = (Dwarf_Off) -1l; 82 return 1; 83 } 84 85 /* This points into the .debug_info section to the beginning of the 86 CU entry. */ 87 char *bytes = (char *) dwarf->sectiondata[IDX_debug_info]->d_buf + off; 88 89 /* The format of the CU header is described in dwarf2p1 7.5.1: 90 91 1. A 4-byte or 12-byte unsigned integer representing the length 92 of the .debug_info contribution for that compilation unit, not 93 including the length field itself. In the 32-bit DWARF format, 94 this is a 4-byte unsigned integer (which must be less than 95 0xfffffff0); in the 64-bit DWARF format, this consists of the 96 4-byte value 0xffffffff followed by an 8-byte unsigned integer 97 that gives the actual length (see Section 7.2.2). 98 99 2. A 2-byte unsigned integer representing the version of the 100 DWARF information for that compilation unit. For DWARF Version 101 2.1, the value in this field is 2. 102 103 3. A 4-byte or 8-byte unsigned offset into the .debug_abbrev 104 section. This offset associates the compilation unit with a 105 particular set of debugging information entry abbreviations. In 106 the 32-bit DWARF format, this is a 4-byte unsigned length; in 107 the 64-bit DWARF format, this is an 8-byte unsigned length (see 108 Section 7.4). 109 110 4. A 1-byte unsigned integer representing the size in bytes of 111 an address on the target architecture. If the system uses 112 segmented addressing, this value represents the size of the 113 offset portion of an address. */ 114 uint64_t length = read_4ubyte_unaligned_inc (dwarf, bytes); 115 size_t offset_size = 4; 116 /* Lengths of 0xfffffff0 - 0xffffffff are escape codes. Oxffffffff is 117 used to indicate that 64-bit dwarf information is being used, the 118 other values are currently reserved. */ 119 if (length == DWARF3_LENGTH_64_BIT) 120 offset_size = 8; 121 else if (unlikely (length >= DWARF3_LENGTH_MIN_ESCAPE_CODE 122 && length <= DWARF3_LENGTH_MAX_ESCAPE_CODE)) 123 { 124 __libdw_seterrno (DWARF_E_INVALID_DWARF); 125 return -1; 126 } 127 128 /* Now we know how large the header is. */ 129 if (unlikely (DIE_OFFSET_FROM_CU_OFFSET (off, offset_size) 130 >= dwarf->sectiondata[IDX_debug_info]->d_size)) 131 { 132 *next_off = -1; 133 return 1; 134 } 135 136 if (length == DWARF3_LENGTH_64_BIT) 137 /* This is a 64-bit DWARF format. */ 138 length = read_8ubyte_unaligned_inc (dwarf, bytes); 139 140 /* Read the version stamp. Always a 16-bit value. 141 XXX Do we need the value? */ 142 read_2ubyte_unaligned_inc (dwarf, bytes); 143 144 /* Get offset in .debug_abbrev. Note that the size of the entry 145 depends on whether this is a 32-bit or 64-bit DWARF definition. */ 146 uint64_t abbrev_offset; 147 if (offset_size == 4) 148 abbrev_offset = read_4ubyte_unaligned_inc (dwarf, bytes); 149 else 150 abbrev_offset = read_8ubyte_unaligned_inc (dwarf, bytes); 151 if (abbrev_offsetp != NULL) 152 *abbrev_offsetp = abbrev_offset; 153 154 /* The address size. Always an 8-bit value. */ 155 uint8_t address_size = *bytes++; 156 if (address_sizep != NULL) 157 *address_sizep = address_size; 158 159 /* Store the offset size. */ 160 if (offset_sizep != NULL) 161 *offset_sizep = offset_size; 162 163 /* Store the header length. */ 164 if (header_sizep != NULL) 165 *header_sizep = (bytes 166 - ((char *) dwarf->sectiondata[IDX_debug_info]->d_buf 167 + off)); 168 169 /* See definition of DIE_OFFSET_FROM_CU_OFFSET macro 170 for an explanation of the trick in this expression. */ 171 *next_off = off + 2 * offset_size - 4 + length; 172 173 return 0; 174 } 175 INTDEF(dwarf_nextcu) 176
