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 <system.h>
29
30
31 int
main(int argc,char * argv[])32 main (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 ("\
92 Failed 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