1 /* $NetBSD: elf_begin.c,v 1.3 2016/02/20 02:43:42 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 1.3 2016/02/20 02:43:42 christos Exp $"); 34 ELFTC_VCSID("Id: elf_begin.c 2364 2011-12-28 17:55:25Z jkoshy "); 35 36 Elf * 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