1/* Copyright (C) 2012 Red Hat, Inc.
2   This file is part of elfutils.
3
4   This file is free software; you can redistribute it and/or modify
5   it under the terms of the GNU General Public License as published by
6   the Free Software Foundation; either version 3 of the License, or
7   (at your option) any later version.
8
9   elfutils is distributed in the hope that it will be useful, but
10   WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12   GNU General Public License for more details.
13
14   You should have received a copy of the GNU General Public License
15   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
16
17#ifdef HAVE_CONFIG_H
18# include <config.h>
19#endif
20
21#include <sys/types.h>
22#include <sys/stat.h>
23#include <stdio.h>
24#include <stdlib.h>
25#include <unistd.h>
26#include <errno.h>
27#include <string.h>
28#include <fcntl.h>
29#include <gelf.h>
30#include <libelf.h>
31#include <stdbool.h>
32#include <inttypes.h>
33
34int
35main (int argc, char *argv[])
36{
37  if (argc != 3)
38    {
39      fprintf (stderr, "Needs two arguments.\n");
40      fprintf (stderr, "First needs to be 'READ', 'MMAP' or 'FDREAD'\n");
41      fprintf (stderr, "Second is the ELF file to read.\n");
42      exit (2); /* user error */
43    }
44
45  bool do_mmap = false;
46  bool close_fd = false;
47  if (strcmp (argv[1], "READ") == 0)
48    {
49      do_mmap = false;
50      close_fd = false;
51    }
52  else if (strcmp (argv[1], "MMAP") == 0)
53    {
54      do_mmap = true;
55      close_fd = false;
56    }
57  else if  (strcmp (argv[1], "FDREAD") == 0)
58    {
59      do_mmap = false;
60      close_fd = true;
61    }
62  else
63    {
64      fprintf (stderr, "First arg needs to be 'READ', 'MMAP' or 'FDREAD'\n");
65      exit (2); /* user error */
66    }
67
68  elf_version (EV_CURRENT);
69
70  int fd = open (argv[2], O_RDONLY);
71  if (fd < 0)
72    {
73      fprintf (stderr, "Cannot open input file %s: %s\n", argv[2],
74	       strerror (errno));
75      exit (2);
76    }
77
78  Elf *elf = elf_begin (fd, do_mmap ? ELF_C_READ_MMAP : ELF_C_READ, NULL);
79  if (elf == NULL)
80    {
81      fprintf (stderr, "elf_begin failed for %s: %s\n", argv[2],
82	       elf_errmsg (-1));
83      exit (2);
84    }
85
86  if (! do_mmap && close_fd)
87    {
88      if (elf_cntl (elf, ELF_C_FDREAD) < 0)
89	{
90	  fprintf (stderr, "elf_cntl failed for %s: %s\n", argv[2],
91		   elf_errmsg (-1));
92	  exit (1);
93	}
94      close (fd);
95    }
96
97  Elf_Scn *scn = NULL;
98  while ((scn = elf_nextscn (elf, scn)) != NULL)
99    {
100      GElf_Shdr shdr_mem;
101      GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
102      printf ("Section at offset %#0" PRIx64 "\n", shdr->sh_offset);
103    }
104
105  elf_end (elf);
106  exit (0);
107}
108