1/* Get symbol information from symbol table at the given index.
2   Copyright (C) 1999, 2000, 2001, 2002, 2005, 2009, 2014, 2015 Red Hat, Inc.
3   This file is part of elfutils.
4   Written by Ulrich Drepper <drepper@redhat.com>, 1999.
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 <assert.h>
35#include <gelf.h>
36#include <string.h>
37
38#include "libelfP.h"
39
40
41GElf_Sym *
42gelf_getsym (Elf_Data *data, int ndx, GElf_Sym *dst)
43{
44  Elf_Data_Scn *data_scn = (Elf_Data_Scn *) data;
45  GElf_Sym *result = NULL;
46
47  if (data == NULL)
48    return NULL;
49
50  if (unlikely (data->d_type != ELF_T_SYM))
51    {
52      __libelf_seterrno (ELF_E_INVALID_HANDLE);
53      return NULL;
54    }
55
56  rwlock_rdlock (data_scn->s->elf->lock);
57
58  /* This is the one place where we have to take advantage of the fact
59     that an `Elf_Data' pointer is also a pointer to `Elf_Data_Scn'.
60     The interface is broken so that it requires this hack.  */
61  if (data_scn->s->elf->class == ELFCLASS32)
62    {
63      Elf32_Sym *src;
64
65      /* Here it gets a bit more complicated.  The format of the symbol
66	 table entries has to be adopted.  The user better has provided
67	 a buffer where we can store the information.  While copying the
68	 data we are converting the format.  */
69      if (INVALID_NDX (ndx, Elf32_Sym, data))
70	{
71	  __libelf_seterrno (ELF_E_INVALID_INDEX);
72	  goto out;
73	}
74
75      src = &((Elf32_Sym *) data->d_buf)[ndx];
76
77      /* This might look like a simple copy operation but it's
78	 not.  There are zero- and sign-extensions going on.  */
79#define COPY(name) \
80      dst->name = src->name
81      COPY (st_name);
82      /* Please note that we can simply copy the `st_info' element since
83	 the definitions of ELFxx_ST_BIND and ELFxx_ST_TYPE are the same
84	 for the 64 bit variant.  */
85      COPY (st_info);
86      COPY (st_other);
87      COPY (st_shndx);
88      COPY (st_value);
89      COPY (st_size);
90    }
91  else
92    {
93      /* If this is a 64 bit object it's easy.  */
94      assert (sizeof (GElf_Sym) == sizeof (Elf64_Sym));
95
96      /* The data is already in the correct form.  Just make sure the
97	 index is OK.  */
98      if (INVALID_NDX (ndx, GElf_Sym, data))
99	{
100	  __libelf_seterrno (ELF_E_INVALID_INDEX);
101	  goto out;
102	}
103
104      *dst = ((GElf_Sym *) data->d_buf)[ndx];
105    }
106
107  result = dst;
108
109 out:
110  rwlock_unlock (data_scn->s->elf->lock);
111
112  return result;
113}
114INTDEF(gelf_getsym)
115