1 /* Return number of program headers in the ELF file.
2 Copyright (C) 2010, 2014, 2015, 2016 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 <stddef.h>
36
37 #include "libelfP.h"
38
39
40 int
41 internal_function
__elf_getphdrnum_rdlock(Elf * elf,size_t * dst)42 __elf_getphdrnum_rdlock (Elf *elf, size_t *dst)
43 {
44 if (unlikely (elf->state.elf64.ehdr == NULL))
45 {
46 /* Maybe no ELF header was created yet. */
47 __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR);
48 return -1;
49 }
50
51 *dst = (elf->class == ELFCLASS32
52 ? elf->state.elf32.ehdr->e_phnum
53 : elf->state.elf64.ehdr->e_phnum);
54
55 if (*dst == PN_XNUM)
56 {
57 const Elf_ScnList *const scns = (elf->class == ELFCLASS32
58 ? &elf->state.elf32.scns
59 : &elf->state.elf64.scns);
60
61 /* If there are no section headers, perhaps this is really just 65536
62 written without PN_XNUM support. Either that or it's bad data. */
63
64 if (elf->class == ELFCLASS32)
65 {
66 if (likely (scns->cnt > 0
67 && elf->state.elf32.scns.data[0].shdr.e32 != NULL))
68 *dst = scns->data[0].shdr.e32->sh_info;
69 }
70 else
71 {
72 if (likely (scns->cnt > 0
73 && elf->state.elf64.scns.data[0].shdr.e64 != NULL))
74 *dst = scns->data[0].shdr.e64->sh_info;
75 }
76 }
77
78 return 0;
79 }
80
81 int
82 internal_function
__elf_getphdrnum_chk_rdlock(Elf * elf,size_t * dst)83 __elf_getphdrnum_chk_rdlock (Elf *elf, size_t *dst)
84 {
85 int result = __elf_getphdrnum_rdlock (elf, dst);
86
87 /* If the phdrs haven't been created or read in yet then do some
88 sanity checking to make sure phnum and phoff are consistent. */
89 if (elf->state.elf.phdr == NULL)
90 {
91 Elf64_Off off = (elf->class == ELFCLASS32
92 ? elf->state.elf32.ehdr->e_phoff
93 : elf->state.elf64.ehdr->e_phoff);
94 if (unlikely (off == 0))
95 {
96 *dst = 0;
97 return result;
98 }
99
100 if (unlikely (off >= elf->maximum_size))
101 {
102 __libelf_seterrno (ELF_E_INVALID_DATA);
103 return -1;
104 }
105
106 /* Check for too many sections. */
107 size_t phdr_size = (elf->class == ELFCLASS32
108 ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr));
109 if (unlikely (*dst > SIZE_MAX / phdr_size))
110 {
111 __libelf_seterrno (ELF_E_INVALID_DATA);
112 return -1;
113 }
114
115 /* Truncated file? Don't return more than can be indexed. */
116 if (unlikely (elf->maximum_size - off < *dst * phdr_size))
117 *dst = (elf->maximum_size - off) / phdr_size;
118 }
119
120 return result;
121 }
122
123 int
elf_getphdrnum(Elf * elf,size_t * dst)124 elf_getphdrnum (Elf *elf, size_t *dst)
125 {
126 int result;
127
128 if (elf == NULL)
129 return -1;
130
131 if (unlikely (elf->kind != ELF_K_ELF))
132 {
133 __libelf_seterrno (ELF_E_INVALID_HANDLE);
134 return -1;
135 }
136
137 rwlock_rdlock (elf->lock);
138 result = __elf_getphdrnum_chk_rdlock (elf, dst);
139 rwlock_unlock (elf->lock);
140
141 return result;
142 }
143