1260684Skaiw/*- 2260684Skaiw * Copyright (c) 2006,2008 Joseph Koshy 3260684Skaiw * All rights reserved. 4260684Skaiw * 5260684Skaiw * Redistribution and use in source and binary forms, with or without 6260684Skaiw * modification, are permitted provided that the following conditions 7260684Skaiw * are met: 8260684Skaiw * 1. Redistributions of source code must retain the above copyright 9260684Skaiw * notice, this list of conditions and the following disclaimer. 10260684Skaiw * 2. Redistributions in binary form must reproduce the above copyright 11260684Skaiw * notice, this list of conditions and the following disclaimer in the 12260684Skaiw * documentation and/or other materials provided with the distribution. 13260684Skaiw * 14260684Skaiw * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15260684Skaiw * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16260684Skaiw * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17260684Skaiw * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18260684Skaiw * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19260684Skaiw * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20260684Skaiw * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21260684Skaiw * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22260684Skaiw * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23260684Skaiw * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24260684Skaiw * SUCH DAMAGE. 25260684Skaiw */ 26260684Skaiw 27260684Skaiw#include <ar.h> 28260684Skaiw#include <assert.h> 29260684Skaiw#include <libelf.h> 30260684Skaiw 31260684Skaiw#include "_libelf.h" 32260684Skaiw 33367466SdimELFTC_VCSID("$Id: elf_next.c 3710 2019-03-12 09:42:35Z jkoshy $"); 34260684Skaiw 35260684SkaiwElf_Cmd 36260684Skaiwelf_next(Elf *e) 37260684Skaiw{ 38260684Skaiw off_t next; 39260684Skaiw Elf *parent; 40260684Skaiw 41260684Skaiw if (e == NULL) 42260684Skaiw return (ELF_C_NULL); 43260684Skaiw 44260684Skaiw if ((parent = e->e_parent) == NULL) { 45260684Skaiw LIBELF_SET_ERROR(ARGUMENT, 0); 46260684Skaiw return (ELF_C_NULL); 47260684Skaiw } 48260684Skaiw 49276371Semaste assert(parent->e_kind == ELF_K_AR); 50276371Semaste assert(parent->e_cmd == ELF_C_READ); 51260684Skaiw assert(e->e_rawfile > parent->e_rawfile); 52260684Skaiw 53276371Semaste next = e->e_rawfile - parent->e_rawfile + (off_t) e->e_rawsize; 54260684Skaiw next = (next + 1) & ~1; /* round up to an even boundary */ 55260684Skaiw 56276371Semaste /* 57276371Semaste * Setup the 'e_next' field of the archive descriptor for the 58276371Semaste * next call to 'elf_begin()'. 59276371Semaste */ 60260684Skaiw parent->e_u.e_ar.e_next = (next >= (off_t) parent->e_rawsize) ? 61260684Skaiw (off_t) 0 : next; 62260684Skaiw 63367466Sdim /* 64367466Sdim * Return an error if the 'e_next' field falls outside the current 65367466Sdim * file. 66367466Sdim * 67367466Sdim * This check is performed after updating the parent descriptor's 68367466Sdim * 'e_next' field so that the next call to elf_begin(3) will terminate 69367466Sdim * traversal of a too-small archive even if client code forgets to 70367466Sdim * check the return value from elf_next(3). 71367466Sdim */ 72367466Sdim if (next > (off_t) parent->e_rawsize) { 73367466Sdim LIBELF_SET_ERROR(ARGUMENT, 0); 74367466Sdim return (ELF_C_NULL); 75367466Sdim } 76367466Sdim 77260684Skaiw return (ELF_C_READ); 78260684Skaiw} 79