Branch data Line data Source code
1 : : /* Get symbol information and separate section index from symbol table
2 : : at the given index.
3 : : Copyright (C) 2000, 2001, 2002, 2005, 2009, 2014, 2015 Red Hat, Inc.
4 : : This file is part of elfutils.
5 : : Written by Ulrich Drepper <drepper@redhat.com>, 2000.
6 : :
7 : : This file is free software; you can redistribute it and/or modify
8 : : it under the terms of either
9 : :
10 : : * the GNU Lesser General Public License as published by the Free
11 : : Software Foundation; either version 3 of the License, or (at
12 : : your option) any later version
13 : :
14 : : or
15 : :
16 : : * the GNU General Public License as published by the Free
17 : : Software Foundation; either version 2 of the License, or (at
18 : : your option) any later version
19 : :
20 : : or both in parallel, as here.
21 : :
22 : : elfutils is distributed in the hope that it will be useful, but
23 : : WITHOUT ANY WARRANTY; without even the implied warranty of
24 : : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
25 : : General Public License for more details.
26 : :
27 : : You should have received copies of the GNU General Public License and
28 : : the GNU Lesser General Public License along with this program. If
29 : : not, see <http://www.gnu.org/licenses/>. */
30 : :
31 : : #ifdef HAVE_CONFIG_H
32 : : # include <config.h>
33 : : #endif
34 : :
35 : : #include <assert.h>
36 : : #include <gelf.h>
37 : : #include <string.h>
38 : :
39 : : #include "libelfP.h"
40 : :
41 : :
42 : : GElf_Sym *
43 : 46698546 : gelf_getsymshndx (Elf_Data *symdata, Elf_Data *shndxdata, int ndx,
44 : : GElf_Sym *dst, Elf32_Word *dstshndx)
45 : : {
46 : 46698546 : Elf_Data_Scn *symdata_scn = (Elf_Data_Scn *) symdata;
47 : 46698546 : Elf_Data_Scn *shndxdata_scn = (Elf_Data_Scn *) shndxdata;
48 : 46698546 : GElf_Sym *result = NULL;
49 : 46698546 : Elf32_Word shndx = 0;
50 : :
51 [ - + ]: 46698546 : if (symdata == NULL)
52 : : return NULL;
53 : :
54 [ + - ]: 46698546 : if (unlikely (symdata->d_type != ELF_T_SYM)
55 [ + + ]: 46698546 : || (likely (shndxdata_scn != NULL)
56 [ - + ]: 1748892 : && unlikely (shndxdata->d_type != ELF_T_WORD)))
57 : : {
58 : 0 : __libelf_seterrno (ELF_E_INVALID_HANDLE);
59 : 0 : return NULL;
60 : : }
61 : :
62 : 46698546 : rwlock_rdlock (symdata_scn->s->elf->lock);
63 : :
64 : : /* The user is not required to pass a data descriptor for an extended
65 : : section index table. */
66 [ + + ]: 46698546 : if (likely (shndxdata_scn != NULL))
67 : : {
68 [ - + ]: 1748892 : if (INVALID_NDX (ndx, Elf32_Word, &shndxdata_scn->d))
69 : : {
70 : 0 : __libelf_seterrno (ELF_E_INVALID_INDEX);
71 : 0 : goto out;
72 : : }
73 : :
74 : 1748892 : shndx = ((Elf32_Word *) shndxdata_scn->d.d_buf)[ndx];
75 : : }
76 : :
77 : : /* This is the one place where we have to take advantage of the fact
78 : : that an `Elf_Data' pointer is also a pointer to `Elf_Data_Scn'.
79 : : The interface is broken so that it requires this hack. */
80 [ + + ]: 46698546 : if (symdata_scn->s->elf->class == ELFCLASS32)
81 : : {
82 : 564450 : Elf32_Sym *src;
83 : :
84 : : /* Here it gets a bit more complicated. The format of the symbol
85 : : table entries has to be adopted. The user better has provided
86 : : a buffer where we can store the information. While copying the
87 : : data we are converting the format. */
88 [ - + ]: 564450 : if (INVALID_NDX (ndx, Elf32_Sym, symdata))
89 : : {
90 : 0 : __libelf_seterrno (ELF_E_INVALID_INDEX);
91 : 0 : goto out;
92 : : }
93 : :
94 : 564450 : src = &((Elf32_Sym *) symdata->d_buf)[ndx];
95 : :
96 : : /* This might look like a simple copy operation but it's
97 : : not. There are zero- and sign-extensions going on. */
98 : : #define COPY(name) \
99 : : dst->name = src->name
100 : 564450 : COPY (st_name);
101 : : /* Please note that we can simply copy the `st_info' element since
102 : : the definitions of ELFxx_ST_BIND and ELFxx_ST_TYPE are the same
103 : : for the 64 bit variant. */
104 : 564450 : COPY (st_info);
105 : 564450 : COPY (st_other);
106 : 564450 : COPY (st_shndx);
107 : 564450 : COPY (st_value);
108 : 564450 : COPY (st_size);
109 : : }
110 : : else
111 : : {
112 : : /* If this is a 64 bit object it's easy. */
113 : 46134096 : assert (sizeof (GElf_Sym) == sizeof (Elf64_Sym));
114 : :
115 : : /* The data is already in the correct form. Just make sure the
116 : : index is OK. */
117 [ - + ]: 46134096 : if (INVALID_NDX (ndx, GElf_Sym, symdata))
118 : : {
119 : 0 : __libelf_seterrno (ELF_E_INVALID_INDEX);
120 : 0 : goto out;
121 : : }
122 : :
123 : 46134096 : *dst = ((GElf_Sym *) symdata->d_buf)[ndx];
124 : : }
125 : :
126 : : /* Now we can store the section index. */
127 [ + - ]: 46698546 : if (dstshndx != NULL)
128 : 46698546 : *dstshndx = shndx;
129 : :
130 : : result = dst;
131 : :
132 : 46698546 : out:
133 : 46698546 : rwlock_unlock (symdata_scn->s->elf->lock);
134 : :
135 : 46698546 : return result;
136 : : }
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