external/bsd/libelf/dist/elf_begin.c

   1 /*      $NetBSD: elf_begin.c,v 1.3 2009/12/20 23:23:46 thorpej Exp $    */
   2
   3 /*-
   4  * Copyright (c) 2006 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 /* __FBSDID("$FreeBSD: src/lib/libelf/elf_begin.c,v 1.1.10.1.2.1 2009/10/25 01:10:29 kensmith Exp $"); */
  31
  32 #include <sys/types.h>
  33 #include <sys/mman.h>
  34 #include <sys/stat.h>
  35
  36 #include <ar.h>
  37 #include <ctype.h>
  38 #include <errno.h>
  39 #include <libelf.h>
  40
  41 #include "_libelf.h"
  42
  43 static Elf *
  44 _libelf_open_object(int fd, Elf_Cmd c)
  45 {
  46         Elf *e;
  47         void *m;
  48         struct stat sb;
  49
  50         /*
  51          * 'Raw' files are always mapped with 'PROT_READ'.  At
  52          * elf_update(3) time for files opened with ELF_C_RDWR the
  53          * mapping is unmapped, file data is written to using write(2)
  54          * and then the raw data is immediately mapped back in.
  55          */
  56         if (fstat(fd, &sb) < 0) {
  57                 LIBELF_SET_ERROR(IO, errno);
  58                 return (NULL);
  59         }
  60
  61         m = NULL;
  62         if ((m = mmap(NULL, (size_t) sb.st_size, PROT_READ, MAP_PRIVATE, fd,
  63             (off_t) 0)) == MAP_FAILED) {
  64                 LIBELF_SET_ERROR(IO, errno);
  65                 return (NULL);
  66         }
  67
  68         if ((e = elf_memory(m, (size_t) sb.st_size)) == NULL) {
  69                 (void) munmap(m, (size_t) sb.st_size);
  70                 return (NULL);
  71         }
  72
  73         e->e_flags |= LIBELF_F_MMAP;
  74         e->e_fd = fd;
  75         e->e_cmd = c;
  76
  77         if (c == ELF_C_RDWR && e->e_kind == ELF_K_AR) {
  78                 (void) elf_end(e);
  79                 LIBELF_SET_ERROR(ARGUMENT, 0);
  80                 return (NULL);
  81         }
  82
  83         return (e);
  84 }
  85
  86 Elf *
  87 elf_begin(int fd, Elf_Cmd c, Elf *a)
  88 {
  89         Elf *e;
  90
  91         e = NULL;
  92
  93         if (LIBELF_PRIVATE(version) == EV_NONE) {
  94                 LIBELF_SET_ERROR(SEQUENCE, 0);
  95                 return (NULL);
  96         }
  97
  98         switch (c) {
  99         case ELF_C_NULL:
 100                 return (NULL);
 101
 102         case ELF_C_WRITE:
 103
 104                 if (a != NULL) { /* not allowed for ar(1) archives. */
 105                         LIBELF_SET_ERROR(ARGUMENT, 0);
 106                         return (NULL);
 107                 }
 108
 109                 /*
 110                  * Check writeability of `fd' immediately and fail if
 111                  * not writeable.
 112                  */
 113                 if (ftruncate(fd, (off_t) 0) < 0) {
 114                         LIBELF_SET_ERROR(IO, errno);
 115                         return (NULL);
 116                 }
 117
 118                 if ((e = _libelf_allocate_elf()) != NULL) {
 119                         _libelf_init_elf(e, ELF_K_ELF);
 120                         e->e_byteorder = _libelf_host_byteorder();
 121                         e->e_fd = fd;
 122                         e->e_cmd = c;
 123                 }
 124                 return (e);
 125
 126         case ELF_C_RDWR:
 127                 if (a != NULL) { /* not allowed for ar(1) archives. */
 128                         LIBELF_SET_ERROR(ARGUMENT, 0);
 129                         return (NULL);
 130                 }
 131                 /*FALLTHROUGH*/
 132         case ELF_C_READ:
 133                 /*
 134                  * Descriptor `a' could be for a regular ELF file, or
 135                  * for an ar(1) archive.
 136                  */
 137                 if (a && (a->e_fd != fd || c != a->e_cmd)) {
 138                         LIBELF_SET_ERROR(ARGUMENT, 0);
 139                         return (NULL);
 140                 }
 141
 142                 break;
 143
 144         default:
 145                 LIBELF_SET_ERROR(ARGUMENT, 0);
 146                 return (NULL);
 147
 148         }
 149
 150         if (a == NULL)
 151                 e = _libelf_open_object(fd, c);
 152         else if (a->e_kind == ELF_K_AR)
 153                 e = _libelf_ar_open_member(fd, c, a);
 154         else
 155                 (e = a)->e_activations++;
 156
 157         return (e);
 158 }