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1 : : /* Get information from auxiliary vector at the given index. 2 : : Copyright (C) 2007, 2015 Red Hat, Inc. 3 : : This file is part of elfutils. 4 : : 5 : : This file is free software; you can redistribute it and/or modify 6 : : it under the terms of either 7 : : 8 : : * the GNU Lesser General Public License as published by the Free 9 : : Software Foundation; either version 3 of the License, or (at 10 : : your option) any later version 11 : : 12 : : or 13 : : 14 : : * the GNU General Public License as published by the Free 15 : : Software Foundation; either version 2 of the License, or (at 16 : : your option) any later version 17 : : 18 : : or both in parallel, as here. 19 : : 20 : : elfutils is distributed in the hope that it will be useful, but 21 : : WITHOUT ANY WARRANTY; without even the implied warranty of 22 : : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 23 : : General Public License for more details. 24 : : 25 : : You should have received copies of the GNU General Public License and 26 : : the GNU Lesser General Public License along with this program. If 27 : : not, see <http://www.gnu.org/licenses/>. */ 28 : : 29 : : #ifdef HAVE_CONFIG_H 30 : : # include <config.h> 31 : : #endif 32 : : 33 : : #include <assert.h> 34 : : #include <gelf.h> 35 : : #include <string.h> 36 : : 37 : : #include "libelfP.h" 38 : : 39 : : 40 : : GElf_auxv_t * 41 : 336 : gelf_getauxv (Elf_Data *data, int ndx, GElf_auxv_t *dst) 42 : : { 43 : 336 : Elf_Data_Scn *data_scn = (Elf_Data_Scn *) data; 44 : 336 : GElf_auxv_t *result = NULL; 45 : 336 : Elf *elf; 46 : : 47 [ - + ]: 336 : if (data_scn == NULL) 48 : : return NULL; 49 : : 50 [ - + ]: 336 : if (unlikely (data_scn->d.d_type != ELF_T_AUXV)) 51 : : { 52 : 0 : __libelf_seterrno (ELF_E_INVALID_HANDLE); 53 : 0 : return NULL; 54 : : } 55 : : 56 : 336 : elf = data_scn->s->elf; 57 : : 58 : 336 : rwlock_rdlock (elf->lock); 59 : : 60 : : /* This is the one place where we have to take advantage of the fact 61 : : that an `Elf_Data' pointer is also a pointer to `Elf_Data_Scn'. 62 : : The interface is broken so that it requires this hack. */ 63 [ + + ]: 336 : if (elf->class == ELFCLASS32) 64 : : { 65 : 186 : Elf32_auxv_t *src; 66 : : 67 : : /* Here it gets a bit more complicated. The format of the vector 68 : : entries has to be converted. The user better have provided a 69 : : buffer where we can store the information. While copying the data 70 : : we convert the format. */ 71 [ - + ]: 186 : if (unlikely ((ndx + 1) * sizeof (Elf32_auxv_t) > data_scn->d.d_size)) 72 : : { 73 : 0 : __libelf_seterrno (ELF_E_INVALID_INDEX); 74 : 0 : goto out; 75 : : } 76 : : 77 : 186 : src = &((Elf32_auxv_t *) data_scn->d.d_buf)[ndx]; 78 : : 79 : : /* This might look like a simple copy operation but it's 80 : : not. There are zero- and sign-extensions going on. */ 81 : 186 : dst->a_type = src->a_type; 82 : 186 : dst->a_un.a_val = src->a_un.a_val; 83 : : } 84 : : else 85 : : { 86 : : /* If this is a 64 bit object it's easy. */ 87 : 150 : assert (sizeof (GElf_auxv_t) == sizeof (Elf64_auxv_t)); 88 : : 89 : : /* The data is already in the correct form. Just make sure the 90 : : index is OK. */ 91 [ - + ]: 150 : if (unlikely ((ndx + 1) * sizeof (GElf_auxv_t) > data_scn->d.d_size)) 92 : : { 93 : 0 : __libelf_seterrno (ELF_E_INVALID_INDEX); 94 : 0 : goto out; 95 : : } 96 : : 97 : 150 : memcpy (dst, data_scn->d.d_buf + ndx * sizeof (GElf_auxv_t), 98 : : sizeof (GElf_auxv_t)); 99 : : } 100 : : 101 : : result = dst; 102 : : 103 : : out: 104 : : rwlock_unlock (elf->lock); 105 : : 106 : : return result; 107 : : }