lib/libelf/elf_next.c

   1 /*-
   2  * Copyright (c) 2006,2008 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 <sys/cdefs.h>
  28
  29 #include <ar.h>
  30 #include <assert.h>
  31 #include <libelf.h>
  32
  33 #include "_libelf.h"
  34
  35 LIBELF_VCSID("$Id$");
  36
  37 Elf_Cmd
  38 elf_next(Elf *e)
  39 {
  40         off_t next;
  41         Elf *parent;
  42
  43         if (e == NULL)
  44                 return (ELF_C_NULL);
  45
  46          if ((parent = e->e_parent) == NULL) {
  47                  LIBELF_SET_ERROR(ARGUMENT, 0);
  48                  return (ELF_C_NULL);
  49          }
  50
  51         assert (parent->e_kind == ELF_K_AR);
  52         assert (parent->e_cmd == ELF_C_READ);
  53         assert(e->e_rawfile > parent->e_rawfile);
  54
  55         next = e->e_rawfile - parent->e_rawfile + e->e_rawsize;
  56         next = (next + 1) & ~1; /* round up to an even boundary */
  57
  58         parent->e_u.e_ar.e_next = (next >= (off_t) parent->e_rawsize) ? (off_t) 0 : next;
  59
  60         return (ELF_C_READ);
  61 }