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