1 /* $NetBSD: elf_next.c,v 1.5 2024/03/03 17:37:33 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2006,2008 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 #if HAVE_NBTOOL_CONFIG_H 30 # include "nbtool_config.h" 31 #endif 32 33 #include <sys/cdefs.h> 34 35 #include <ar.h> 36 #include <assert.h> 37 #include <libelf.h> 38 39 #include "_libelf.h" 40 41 __RCSID("$NetBSD: elf_next.c,v 1.5 2024/03/03 17:37:33 christos Exp $"); 42 43 Elf_Cmd 44 elf_next(Elf *e) 45 { 46 off_t next; 47 Elf *parent; 48 49 if (e == NULL) 50 return (ELF_C_NULL); 51 52 if ((parent = e->e_parent) == NULL) { 53 LIBELF_SET_ERROR(ARGUMENT, 0); 54 return (ELF_C_NULL); 55 } 56 57 assert(parent->e_kind == ELF_K_AR); 58 assert(parent->e_cmd == ELF_C_READ); 59 assert(e->e_rawfile > parent->e_rawfile); 60 61 next = e->e_rawfile - parent->e_rawfile + (off_t) e->e_rawsize; 62 next = (next + 1) & ~1; /* round up to an even boundary */ 63 64 /* 65 * Setup the 'e_next' field of the archive descriptor for the 66 * next call to 'elf_begin()'. 67 */ 68 parent->e_u.e_ar.e_next = (next >= (off_t) parent->e_rawsize) ? 69 (off_t) 0 : next; 70 71 /* 72 * Return an error if the 'e_next' field falls outside the current 73 * file. 74 * 75 * This check is performed after updating the parent descriptor's 76 * 'e_next' field so that the next call to elf_begin(3) will terminate 77 * traversal of a too-small archive even if client code forgets to 78 * check the return value from elf_next(3). 79 */ 80 if (next > (off_t) parent->e_rawsize) { 81 LIBELF_SET_ERROR(ARGUMENT, 0); 82 return (ELF_C_NULL); 83 } 84 85 return (ELF_C_READ); 86 } 87