1 /* Return sibling of given DIE. 2 Copyright (C) 2003-2010, 2014, 2015 Red Hat, Inc. 3 This file is part of elfutils. 4 Written by Ulrich Drepper <drepper (at) 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 "libdwP.h" 35 #include <dwarf.h> 36 #include <string.h> 37 38 39 int 40 dwarf_siblingof (Dwarf_Die *die, Dwarf_Die *result) 41 { 42 /* Ignore previous errors. */ 43 if (die == NULL) 44 return -1; 45 46 /* result is declared NN */ 47 48 if (result != die) 49 result->addr = NULL; 50 51 unsigned int level = 0; 52 53 /* Copy of the current DIE. */ 54 Dwarf_Die this_die = *die; 55 /* Temporary attributes we create. */ 56 Dwarf_Attribute sibattr; 57 /* Copy of the CU in the request. */ 58 sibattr.cu = this_die.cu; 59 /* That's the address we start looking. */ 60 unsigned char *addr = this_die.addr; 61 /* End of the buffer. */ 62 unsigned char *endp = sibattr.cu->endp; 63 64 /* Search for the beginning of the next die on this level. We 65 must not return the dies for children of the given die. */ 66 do 67 { 68 /* Find the end of the DIE or the sibling attribute. */ 69 addr = __libdw_find_attr (&this_die, DW_AT_sibling, &sibattr.code, 70 &sibattr.form); 71 if (addr != NULL && sibattr.code == DW_AT_sibling) 72 { 73 Dwarf_Off offset; 74 sibattr.valp = addr; 75 if (unlikely (__libdw_formref (&sibattr, &offset) != 0)) 76 /* Something went wrong. */ 77 return -1; 78 79 /* The sibling attribute should point after this DIE in the CU. 80 But not after the end of the CU. */ 81 size_t size = sibattr.cu->endp - sibattr.cu->startp; 82 size_t die_off = this_die.addr - this_die.cu->startp; 83 if (unlikely (offset >= size || offset <= die_off)) 84 { 85 __libdw_seterrno (DWARF_E_INVALID_DWARF); 86 return -1; 87 } 88 89 /* Compute the next address. */ 90 addr = sibattr.cu->startp + offset; 91 } 92 else if (unlikely (addr == NULL) 93 || unlikely (this_die.abbrev == DWARF_END_ABBREV)) 94 return -1; 95 else if (this_die.abbrev->has_children) 96 /* This abbreviation has children. */ 97 ++level; 98 99 100 while (1) 101 { 102 /* Make sure we are still in range. Some producers might skip 103 the trailing NUL bytes. */ 104 if (addr >= endp) 105 return 1; 106 107 if (*addr != '\0') 108 break; 109 110 if (level-- == 0) 111 { 112 if (result != die) 113 result->addr = addr; 114 /* No more sibling at all. */ 115 return 1; 116 } 117 118 ++addr; 119 } 120 121 /* Initialize the 'current DIE'. */ 122 this_die.addr = addr; 123 this_die.abbrev = NULL; 124 } 125 while (level > 0); 126 127 /* Maybe we reached the end of the CU. */ 128 if (addr >= endp) 129 return 1; 130 131 /* Clear the entire DIE structure. This signals we have not yet 132 determined any of the information. */ 133 memset (result, '\0', sizeof (Dwarf_Die)); 134 135 /* We have the address. */ 136 result->addr = addr; 137 138 /* Same CU as the parent. */ 139 result->cu = sibattr.cu; 140 141 return 0; 142 } 143 INTDEF(dwarf_siblingof) 144
