1 /* $NetBSD: elf_begin.c,v 1.5 2024/03/03 17:37:33 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 <sys/cdefs.h> 30 31 #include <libelf.h> 32 33 #include "_libelf.h" 34 35 __RCSID("$NetBSD: elf_begin.c,v 1.5 2024/03/03 17:37:33 christos Exp $"); 36 ELFTC_VCSID("Id: elf_begin.c 3977 2022-05-01 06:45:34Z jkoshy"); 37 38 Elf * 39 elf_begin(int fd, Elf_Cmd c, Elf *a) 40 { 41 Elf *e; 42 43 e = NULL; 44 45 if (LIBELF_PRIVATE(version) == EV_NONE) { 46 LIBELF_SET_ERROR(SEQUENCE, 0); 47 return (NULL); 48 } 49 50 switch (c) { 51 case ELF_C_NULL: 52 return (NULL); 53 54 case ELF_C_WRITE: 55 /* 56 * The ELF_C_WRITE command is required to ignore the 57 * descriptor passed in. 58 */ 59 a = NULL; 60 break; 61 62 case ELF_C_RDWR: 63 if (a != NULL) { /* not allowed for ar(1) archives. */ 64 LIBELF_SET_ERROR(ARGUMENT, 0); 65 return (NULL); 66 } 67 /*FALLTHROUGH*/ 68 case ELF_C_READ: 69 /* 70 * Descriptor `a' could be for a regular ELF file, or 71 * for an ar(1) archive. If descriptor `a' was opened 72 * using a valid file descriptor, we need to check if 73 * the passed in `fd' value matches the original one. 74 */ 75 if (a && 76 ((a->e_fd != -1 && a->e_fd != fd) || c != a->e_cmd)) { 77 LIBELF_SET_ERROR(ARGUMENT, 0); 78 return (NULL); 79 } 80 break; 81 82 default: 83 LIBELF_SET_ERROR(ARGUMENT, 0); 84 return (NULL); 85 86 } 87 88 if (a == NULL) 89 e = _libelf_open_object(fd, c, 1); 90 else if (a->e_kind == ELF_K_AR) 91 e = _libelf_ar_open_member(a->e_fd, c, a); 92 else 93 (e = a)->e_activations++; 94 95 return (e); 96 } 97