1/* Copyright (C) 1999, 2000, 2002 Red Hat, Inc.
2   This file is part of elfutils.
3   Written by Ulrich Drepper <drepper@redhat.com>, 1999.
4
5   This file is free software; you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation; either version 3 of the License, or
8   (at your option) any later version.
9
10   elfutils is distributed in the hope that it will be useful, but
11   WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   GNU General Public License for more details.
14
15   You should have received a copy of the GNU General Public License
16   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
17
18#ifdef HAVE_CONFIG_H
19# include <config.h>
20#endif
21
22#include <fcntl.h>
23#include <gelf.h>
24#include <stdio.h>
25#include <stdlib.h>
26#include <string.h>
27#include <unistd.h>
28#include <sys/param.h>
29
30
31int
32main (int argc, char *argv[])
33{
34  int fd;
35  Elf *elf;
36  Elf *subelf;
37  Elf_Cmd cmd;
38  off_t offset;
39  size_t todo;
40
41  if (argc < 4)
42    exit (1);
43
44  /* Open the archive.  */
45  fd = open (argv[1], O_RDONLY);
46  if (fd == -1)
47    {
48      printf ("Cannot open input file: %m");
49      exit (1);
50    }
51
52  /* Set the ELF version.  */
53  elf_version (EV_CURRENT);
54
55  /* Create an ELF descriptor.  */
56  cmd = ELF_C_READ;
57  elf = elf_begin (fd, cmd, NULL);
58  if (elf == NULL)
59    {
60      printf ("Cannot create ELF descriptor: %s\n", elf_errmsg (-1));
61      exit (1);
62    }
63
64  /* If it is no archive punt.  */
65  if (elf_kind (elf) != ELF_K_AR)
66    {
67      printf ("`%s' is no archive\n", argv[1]);
68      exit (1);
69    }
70
71  /* Get the elements of the archive one after the other.  */
72  while ((subelf = elf_begin (fd, cmd, elf)) != NULL)
73    {
74      /* The the header for this element.  */
75      Elf_Arhdr *arhdr = elf_getarhdr (subelf);
76
77      if (arhdr == NULL)
78	{
79	  printf ("cannot get arhdr: %s\n", elf_errmsg (-1));
80	  exit (1);
81	}
82
83      if (strcmp (arhdr->ar_name, argv[2]) == 0)
84	{
85	  int outfd;
86
87	  /* Get the offset of the file in the archive.  */
88	  offset = elf_getbase (subelf);
89	  if (offset == -1)
90	    {
91	      printf ("\
92Failed to get base address for the archive element: %s\n",
93		      elf_errmsg (-1));
94	      exit (1);
95	    }
96
97	  /* Open the output file.  */
98	  outfd = open (argv[3], O_CREAT | O_TRUNC | O_RDWR, 0666);
99	  if (outfd == -1)
100	    {
101	      printf ("cannot open output file: %m");
102	      exit (1);
103	    }
104
105	  /* Now write out the data.  */
106	  todo = arhdr->ar_size;
107	  while (todo > 0)
108	    {
109	      char buf[1024];
110	      ssize_t n = pread (fd, buf, MIN (sizeof buf, todo), offset);
111	      if (n == 0)
112		break;
113
114	      if (write (outfd, buf, n) != n)
115		{
116		  puts ("Writing output failed");
117		  exit (1);
118		}
119
120	      offset += n;
121	      todo -= n;
122	    }
123
124	  /* Check whether all the date was read and written out.  */
125	  if (todo != 0)
126	    {
127	      puts ("Reading archive member failed.");
128	      exit (1);
129	    }
130
131	  /* Close the descriptors.  */
132	  if (elf_end (subelf) != 0 || elf_end (elf) != 0)
133	    {
134	      printf ("Freeing ELF descriptors failed: %s", elf_errmsg (-1));
135	      exit (1);
136	    }
137
138	  close (outfd);
139	  close (fd);
140
141	  /* All went well.  */
142	  exit (0);
143	}
144
145      /* Get next archive element.  */
146      cmd = elf_next (subelf);
147      if (elf_end (subelf) != 0)
148	{
149	  printf ("error while freeing sub-ELF descriptor: %s\n",
150		  elf_errmsg (-1));
151	  exit (1);
152	}
153    }
154
155  /* When we reach this point we haven't found the given file in the
156     archive.  */
157  printf ("File `%s' not found in archive\n", argv[2]);
158  exit (1);
159}
160