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