1/* Return number of program headers in the ELF file.
2   Copyright (C) 2010, 2014, 2015 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
40int
41internal_function
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
81int
82internal_function
83__elf_getphdrnum_chk_rdlock (Elf *elf, size_t *dst)
84{
85  int result = __elf_getphdrnum_rdlock (elf, dst);
86
87  /* Do some sanity checking to make sure phnum and phoff are consistent.  */
88  Elf64_Off off = (elf->class == ELFCLASS32
89		   ? elf->state.elf32.ehdr->e_phoff
90		   : elf->state.elf64.ehdr->e_phoff);
91  if (unlikely (off == 0))
92    {
93      *dst = 0;
94      return result;
95    }
96
97  if (unlikely (off >= elf->maximum_size))
98    {
99      __libelf_seterrno (ELF_E_INVALID_DATA);
100      return -1;
101    }
102
103  /* Check for too many sections.  */
104  size_t phdr_size = (elf->class == ELFCLASS32
105		      ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr));
106  if (unlikely (*dst > SIZE_MAX / phdr_size))
107    {
108      __libelf_seterrno (ELF_E_INVALID_DATA);
109      return -1;
110    }
111
112  /* Truncated file?  Don't return more than can be indexed.  */
113  if (unlikely (elf->maximum_size - off < *dst * phdr_size))
114    *dst = (elf->maximum_size - off) / phdr_size;
115
116  return result;
117}
118
119int
120elf_getphdrnum (Elf *elf, size_t *dst)
121{
122  int result;
123
124  if (elf == NULL)
125    return -1;
126
127  if (unlikely (elf->kind != ELF_K_ELF))
128    {
129      __libelf_seterrno (ELF_E_INVALID_HANDLE);
130      return -1;
131    }
132
133  rwlock_rdlock (elf->lock);
134  result = __elf_getphdrnum_chk_rdlock (elf, dst);
135  rwlock_unlock (elf->lock);
136
137  return result;
138}
139