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