1 /* Append new section.
2 Copyright (C) 1998,1999,2000,2001,2002,2005,2009,2014,2015 Red Hat, Inc.
3 This file is part of elfutils.
4 Written by Ulrich Drepper <drepper@redhat.com>, 1998.
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 <stdbool.h>
36 #include <stddef.h>
37 #include <stdlib.h>
38 #include <string.h>
39
40 #include "libelfP.h"
41
42
43 Elf_Scn *
elf_newscn(Elf * elf)44 elf_newscn (Elf *elf)
45 {
46 Elf_Scn *result = NULL;
47 bool first = false;
48
49 if (elf == NULL)
50 return NULL;
51
52 /* We rely on the prefix of the `elf', `elf32', and `elf64' element
53 being the same. */
54 assert (offsetof (Elf, state.elf.scns_last)
55 == offsetof (Elf, state.elf32.scns_last));
56 assert (offsetof (Elf, state.elf.scns_last)
57 == offsetof (Elf, state.elf64.scns_last));
58 assert (offsetof (Elf, state.elf32.scns)
59 == offsetof (Elf, state.elf64.scns));
60
61 rwlock_wrlock (elf->lock);
62
63 again:
64 if (elf->state.elf.scns_last->cnt < elf->state.elf.scns_last->max)
65 {
66 result = &elf->state.elf.scns_last->data[elf->state.elf.scns_last->cnt];
67
68 if (++elf->state.elf.scns_last->cnt == 1
69 && (elf->state.elf.scns_last
70 == (elf->class == ELFCLASS32
71 || (offsetof (Elf, state.elf32.scns)
72 == offsetof (Elf, state.elf64.scns))
73 ? &elf->state.elf32.scns : &elf->state.elf64.scns)))
74 /* This is zeroth section. */
75 first = true;
76 else
77 {
78 assert (elf->state.elf.scns_last->cnt > 1);
79 result->index = result[-1].index + 1;
80 }
81 }
82 else
83 {
84 /* We must allocate a new element. */
85 Elf_ScnList *newp = NULL;
86
87 assert (elf->state.elf.scnincr > 0);
88
89 if (
90 #if SIZE_MAX <= 4294967295U
91 likely (elf->state.elf.scnincr
92 < SIZE_MAX / 2 / sizeof (Elf_Scn) - sizeof (Elf_ScnList))
93 #else
94 1
95 #endif
96 )
97 newp = (Elf_ScnList *) calloc (sizeof (Elf_ScnList)
98 + ((elf->state.elf.scnincr *= 2)
99 * sizeof (Elf_Scn)), 1);
100 if (newp == NULL)
101 {
102 __libelf_seterrno (ELF_E_NOMEM);
103 goto out;
104 }
105
106 result = &newp->data[0];
107
108 /* One section used. */
109 ++newp->cnt;
110
111 /* This is the number of sections we allocated. */
112 newp->max = elf->state.elf.scnincr;
113
114 /* Remember the index for the first section in this block. */
115 newp->data[0].index
116 = 1 + elf->state.elf.scns_last->data[elf->state.elf.scns_last->max - 1].index;
117
118 /* Enqueue the new list element. */
119 elf->state.elf.scns_last = elf->state.elf.scns_last->next = newp;
120 }
121
122 /* Create a section header for this section. */
123 if (elf->class == ELFCLASS32)
124 {
125 result->shdr.e32 = (Elf32_Shdr *) calloc (1, sizeof (Elf32_Shdr));
126 if (result->shdr.e32 == NULL)
127 {
128 __libelf_seterrno (ELF_E_NOMEM);
129 goto out;
130 }
131 }
132 else
133 {
134 result->shdr.e64 = (Elf64_Shdr *) calloc (1, sizeof (Elf64_Shdr));
135 if (result->shdr.e64 == NULL)
136 {
137 __libelf_seterrno (ELF_E_NOMEM);
138 goto out;
139 }
140 }
141
142 result->elf = elf;
143 result->shdr_flags = ELF_F_DIRTY | ELF_F_MALLOCED;
144 result->list = elf->state.elf.scns_last;
145
146 /* Initialize the data part. */
147 result->data_read = 1;
148 if (unlikely (first))
149 {
150 /* For the first section we mark the data as already available. */
151 //result->data_list_rear = &result->data_list;
152 first = false;
153 goto again;
154 }
155
156 result->flags |= ELF_F_DIRTY;
157
158 out:
159 rwlock_unlock (elf->lock);
160
161 return result;
162 }
163