Ulrich Drepper | b08d5a8 | 2005-07-26 05:00:05 +0000 | [diff] [blame^] | 1 | /* Get symbol information and separate section index from symbol table |
| 2 | at the given index. |
| 3 | Copyright (C) 2000, 2001, 2002 Red Hat, Inc. |
| 4 | Written by Ulrich Drepper <drepper@redhat.com>, 2000. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation, version 2. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public License |
| 16 | along with this program; if not, write to the Free Software Foundation, |
| 17 | Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| 18 | |
| 19 | #ifdef HAVE_CONFIG_H |
| 20 | # include <config.h> |
| 21 | #endif |
| 22 | |
| 23 | #include <assert.h> |
| 24 | #include <gelf.h> |
| 25 | #include <string.h> |
| 26 | |
| 27 | #include "libelfP.h" |
| 28 | |
| 29 | |
| 30 | GElf_Sym * |
| 31 | gelf_getsymshndx (symdata, shndxdata, ndx, dst, dstshndx) |
| 32 | Elf_Data *symdata; |
| 33 | Elf_Data *shndxdata; |
| 34 | int ndx; |
| 35 | GElf_Sym *dst; |
| 36 | Elf32_Word *dstshndx; |
| 37 | { |
| 38 | Elf_Data_Scn *symdata_scn = (Elf_Data_Scn *) symdata; |
| 39 | Elf_Data_Scn *shndxdata_scn = (Elf_Data_Scn *) shndxdata; |
| 40 | GElf_Sym *result = NULL; |
| 41 | Elf32_Word shndx = 0; |
| 42 | |
| 43 | if (symdata == NULL) |
| 44 | return NULL; |
| 45 | |
| 46 | if (unlikely (symdata->d_type != ELF_T_SYM) |
| 47 | || (likely (shndxdata_scn != NULL) |
| 48 | && unlikely (shndxdata->d_type != ELF_T_WORD))) |
| 49 | { |
| 50 | __libelf_seterrno (ELF_E_INVALID_HANDLE); |
| 51 | return NULL; |
| 52 | } |
| 53 | |
| 54 | rwlock_rdlock (symdata_scn->s->elf->lock); |
| 55 | |
| 56 | /* The user is not required to pass a data descriptor for an extended |
| 57 | section index table. */ |
| 58 | if (likely (shndxdata_scn != NULL)) |
| 59 | { |
| 60 | if (unlikely ((ndx + 1) * sizeof (Elf32_Word) > shndxdata_scn->d.d_size)) |
| 61 | { |
| 62 | __libelf_seterrno (ELF_E_INVALID_INDEX); |
| 63 | goto out; |
| 64 | } |
| 65 | |
| 66 | shndx = ((Elf32_Word *) shndxdata_scn->d.d_buf)[ndx]; |
| 67 | } |
| 68 | |
| 69 | /* This is the one place where we have to take advantage of the fact |
| 70 | that an `Elf_Data' pointer is also a pointer to `Elf_Data_Scn'. |
| 71 | The interface is broken so that it requires this hack. */ |
| 72 | if (symdata_scn->s->elf->class == ELFCLASS32) |
| 73 | { |
| 74 | Elf32_Sym *src; |
| 75 | |
| 76 | /* Here it gets a bit more complicated. The format of the symbol |
| 77 | table entries has to be adopted. The user better has provided |
| 78 | a buffer where we can store the information. While copying the |
| 79 | data we are converting the format. */ |
| 80 | if (unlikely ((ndx + 1) * sizeof (Elf32_Sym) > symdata->d_size)) |
| 81 | { |
| 82 | __libelf_seterrno (ELF_E_INVALID_INDEX); |
| 83 | goto out; |
| 84 | } |
| 85 | |
| 86 | src = &((Elf32_Sym *) symdata->d_buf)[ndx]; |
| 87 | |
| 88 | /* This might look like a simple copy operation but it's |
| 89 | not. There are zero- and sign-extensions going on. */ |
| 90 | #define COPY(name) \ |
| 91 | dst->name = src->name |
| 92 | COPY (st_name); |
| 93 | /* Please note that we can simply copy the `st_info' element since |
| 94 | the definitions of ELFxx_ST_BIND and ELFxx_ST_TYPE are the same |
| 95 | for the 64 bit variant. */ |
| 96 | COPY (st_info); |
| 97 | COPY (st_other); |
| 98 | COPY (st_shndx); |
| 99 | COPY (st_value); |
| 100 | COPY (st_size); |
| 101 | } |
| 102 | else |
| 103 | { |
| 104 | /* If this is a 64 bit object it's easy. */ |
| 105 | assert (sizeof (GElf_Sym) == sizeof (Elf64_Sym)); |
| 106 | |
| 107 | /* The data is already in the correct form. Just make sure the |
| 108 | index is OK. */ |
| 109 | if (unlikely ((ndx + 1) * sizeof (GElf_Sym) > symdata->d_size)) |
| 110 | { |
| 111 | __libelf_seterrno (ELF_E_INVALID_INDEX); |
| 112 | goto out; |
| 113 | } |
| 114 | |
| 115 | *dst = ((GElf_Sym *) symdata->d_buf)[ndx]; |
| 116 | } |
| 117 | |
| 118 | /* Now we can store the section index. */ |
| 119 | if (dstshndx != NULL) |
| 120 | *dstshndx = shndx; |
| 121 | |
| 122 | result = dst; |
| 123 | |
| 124 | out: |
| 125 | rwlock_unlock (symdata_scn->s->elf->lock); |
| 126 | |
| 127 | return result; |
| 128 | } |