1 /* Helper functions for form handling. 2 Copyright (C) 2003-2009, 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 <dwarf.h> 35 #include <string.h> 36 37 #include "libdwP.h" 38 39 40 size_t 41 internal_function 42 __libdw_form_val_compute_len (struct Dwarf_CU *cu, unsigned int form, 43 const unsigned char *valp) 44 { 45 const unsigned char *startp = valp; 46 const unsigned char *endp = cu->endp; 47 Dwarf_Word u128; 48 size_t result; 49 50 /* NB: This doesn't cover constant form lengths, which are 51 already handled by the inlined __libdw_form_val_len. */ 52 switch (form) 53 { 54 case DW_FORM_addr: 55 result = cu->address_size; 56 break; 57 58 case DW_FORM_ref_addr: 59 result = cu->version == 2 ? cu->address_size : cu->offset_size; 60 break; 61 62 case DW_FORM_strp: 63 case DW_FORM_sec_offset: 64 case DW_FORM_GNU_ref_alt: 65 case DW_FORM_GNU_strp_alt: 66 result = cu->offset_size; 67 break; 68 69 case DW_FORM_block1: 70 if (unlikely ((size_t) (endp - startp) < 1)) 71 goto invalid; 72 result = *valp + 1; 73 break; 74 75 case DW_FORM_block2: 76 if (unlikely ((size_t) (endp - startp) < 2)) 77 goto invalid; 78 result = read_2ubyte_unaligned (cu->dbg, valp) + 2; 79 break; 80 81 case DW_FORM_block4: 82 if (unlikely ((size_t) (endp - startp) < 4)) 83 goto invalid; 84 result = read_4ubyte_unaligned (cu->dbg, valp) + 4; 85 break; 86 87 case DW_FORM_block: 88 case DW_FORM_exprloc: 89 get_uleb128 (u128, valp, endp); 90 result = u128 + (valp - startp); 91 break; 92 93 case DW_FORM_string: 94 { 95 const unsigned char *endstrp = memchr (valp, '\0', 96 (size_t) (endp - startp)); 97 if (unlikely (endstrp == NULL)) 98 goto invalid; 99 result = (size_t) (endstrp - startp) + 1; 100 break; 101 } 102 103 case DW_FORM_sdata: 104 case DW_FORM_udata: 105 case DW_FORM_ref_udata: 106 get_uleb128 (u128, valp, endp); 107 result = valp - startp; 108 break; 109 110 case DW_FORM_indirect: 111 get_uleb128 (u128, valp, endp); 112 // XXX Is this really correct? 113 result = __libdw_form_val_len (cu, u128, valp); 114 if (result != (size_t) -1) 115 result += valp - startp; 116 else 117 return (size_t) -1; 118 break; 119 120 default: 121 goto invalid; 122 } 123 124 if (unlikely (result > (size_t) (endp - startp))) 125 { 126 invalid: 127 __libdw_seterrno (DWARF_E_INVALID_DWARF); 128 result = (size_t) -1; 129 } 130 131 return result; 132 } 133
