1 /* $NetBSD: elf_begin.c,v 1.2 2014/03/09 16:58:04 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2006,2008-2011 Joseph Koshy
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <libelf.h>
30
31 #include "_libelf.h"
32
33 __RCSID("$NetBSD: elf_begin.c,v 1.2 2014/03/09 16:58:04 christos Exp $");
34 ELFTC_VCSID("Id: elf_begin.c 2364 2011-12-28 17:55:25Z jkoshy ");
35
36 Elf *
elf_begin(int fd,Elf_Cmd c,Elf * a)37 elf_begin(int fd, Elf_Cmd c, Elf *a)
38 {
39 Elf *e;
40
41 e = NULL;
42
43 if (LIBELF_PRIVATE(version) == EV_NONE) {
44 LIBELF_SET_ERROR(SEQUENCE, 0);
45 return (NULL);
46 }
47
48 switch (c) {
49 case ELF_C_NULL:
50 return (NULL);
51
52 case ELF_C_WRITE:
53 /*
54 * The ELF_C_WRITE command is required to ignore the
55 * descriptor passed in.
56 */
57 a = NULL;
58 break;
59
60 case ELF_C_RDWR:
61 if (a != NULL) { /* not allowed for ar(1) archives. */
62 LIBELF_SET_ERROR(ARGUMENT, 0);
63 return (NULL);
64 }
65 /*FALLTHROUGH*/
66 case ELF_C_READ:
67 /*
68 * Descriptor `a' could be for a regular ELF file, or
69 * for an ar(1) archive. If descriptor `a' was opened
70 * using a valid file descriptor, we need to check if
71 * the passed in `fd' value matches the original one.
72 */
73 if (a &&
74 ((a->e_fd != -1 && a->e_fd != fd) || c != a->e_cmd)) {
75 LIBELF_SET_ERROR(ARGUMENT, 0);
76 return (NULL);
77 }
78 break;
79
80 default:
81 LIBELF_SET_ERROR(ARGUMENT, 0);
82 return (NULL);
83
84 }
85
86 if (a == NULL)
87 e = _libelf_open_object(fd, c, 1);
88 else if (a->e_kind == ELF_K_AR)
89 e = _libelf_ar_open_member(a->e_fd, c, a);
90 else
91 (e = a)->e_activations++;
92
93 return (e);
94 }
95