external/bsd/elftoolchain/dist/libelf/elf_begin.c

   1 /*      $NetBSD: elf_begin.c,v 1.2 2014/03/09 16:58:04 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 <libelf.h>
  30
  31 #include "_libelf.h"
  32
  33 __RCSID("$NetBSD: elf_begin.c,v 1.2 2014/03/09 16:58:04 christos Exp $");
  34 ELFTC_VCSID("Id: elf_begin.c 2364 2011-12-28 17:55:25Z jkoshy ");
  35
  36 Elf *
  37 elf_begin(int fd, Elf_Cmd c, Elf *a)
  38 {
  39         Elf *e;
  40
  41         e = NULL;
  42
  43         if (LIBELF_PRIVATE(version) == EV_NONE) {
  44                 LIBELF_SET_ERROR(SEQUENCE, 0);
  45                 return (NULL);
  46         }
  47
  48         switch (c) {
  49         case ELF_C_NULL:
  50                 return (NULL);
  51
  52         case ELF_C_WRITE:
  53                 /*
  54                  * The ELF_C_WRITE command is required to ignore the
  55                  * descriptor passed in.
  56                  */
  57                 a = NULL;
  58                 break;
  59
  60         case ELF_C_RDWR:
  61                 if (a != NULL) { /* not allowed for ar(1) archives. */
  62                         LIBELF_SET_ERROR(ARGUMENT, 0);
  63                         return (NULL);
  64                 }
  65                 /*FALLTHROUGH*/
  66         case ELF_C_READ:
  67                 /*
  68                  * Descriptor `a' could be for a regular ELF file, or
  69                  * for an ar(1) archive.  If descriptor `a' was opened
  70                  * using a valid file descriptor, we need to check if
  71                  * the passed in `fd' value matches the original one.
  72                  */
  73                 if (a &&
  74                     ((a->e_fd != -1 && a->e_fd != fd) || c != a->e_cmd)) {
  75                         LIBELF_SET_ERROR(ARGUMENT, 0);
  76                         return (NULL);
  77                 }
  78                 break;
  79
  80         default:
  81                 LIBELF_SET_ERROR(ARGUMENT, 0);
  82                 return (NULL);
  83
  84         }
  85
  86         if (a == NULL)
  87                 e = _libelf_open_object(fd, c, 1);
  88         else if (a->e_kind == ELF_K_AR)
  89                 e = _libelf_ar_open_member(a->e_fd, c, a);
  90         else
  91                 (e = a)->e_activations++;
  92
  93         return (e);
  94 }