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 *dst = 0;
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 {
69 Elf_Scn *scn = &elf->state.elf32.scns.data[0];
70 Elf32_Shdr *shdr = scn->shdr.e32 ?: __elf32_getshdr_rdlock (scn);
71 if (shdr)
72 *dst = shdr->sh_info;
73 }
74 }
75 else
76 {
77 if (likely (scns->cnt > 0))
78 {
79 Elf_Scn *scn = &elf->state.elf64.scns.data[0];
80 Elf64_Shdr *shdr = scn->shdr.e64 ?: __elf64_getshdr_rdlock (scn);
81 if (shdr)
82 *dst = shdr->sh_info;
83 }
84 }
85 }
86
87 return 0;
88 }
89
90 int
91 internal_function
__elf_getphdrnum_chk_rdlock(Elf * elf,size_t * dst)92 __elf_getphdrnum_chk_rdlock (Elf *elf, size_t *dst)
93 {
94 int result = __elf_getphdrnum_rdlock (elf, dst);
95
96 /* If the phdrs haven't been created or read in yet then do some
97 sanity checking to make sure phnum and phoff are consistent. */
98 if (elf->state.elf.phdr == NULL)
99 {
100 Elf64_Off off = (elf->class == ELFCLASS32
101 ? elf->state.elf32.ehdr->e_phoff
102 : elf->state.elf64.ehdr->e_phoff);
103 if (unlikely (off == 0))
104 {
105 *dst = 0;
106 return result;
107 }
108
109 if (unlikely (off >= elf->maximum_size))
110 {
111 __libelf_seterrno (ELF_E_INVALID_DATA);
112 return -1;
113 }
114
115 /* Check for too many sections. */
116 size_t phdr_size = (elf->class == ELFCLASS32
117 ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr));
118 if (unlikely (*dst > SIZE_MAX / phdr_size))
119 {
120 __libelf_seterrno (ELF_E_INVALID_DATA);
121 return -1;
122 }
123
124 /* Truncated file? Don't return more than can be indexed. */
125 if (unlikely (elf->maximum_size - off < *dst * phdr_size))
126 *dst = (elf->maximum_size - off) / phdr_size;
127 }
128
129 return result;
130 }
131
132 int
elf_getphdrnum(Elf * elf,size_t * dst)133 elf_getphdrnum (Elf *elf, size_t *dst)
134 {
135 int result;
136
137 if (elf == NULL)
138 return -1;
139
140 if (unlikely (elf->kind != ELF_K_ELF))
141 {
142 __libelf_seterrno (ELF_E_INVALID_HANDLE);
143 return -1;
144 }
145
146 rwlock_rdlock (elf->lock);
147 result = __elf_getphdrnum_chk_rdlock (elf, dst);
148 rwlock_unlock (elf->lock);
149
150 return result;
151 }
152