lib/libelf/libelf_phdr.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  * $FreeBSD: src/lib/libelf/libelf_phdr.c,v 1.2 2006/12/25 02:22:22 jkoshy Exp $
  27  */
  28
  29 #include <sys/cdefs.h>
  30
  31 #include <assert.h>
  32 #include <gelf.h>
  33 #include <libelf.h>
  34 #include <stdlib.h>
  35
  36 #include "_libelf.h"
  37
  38 LIBELF_VCSID("$Id$");
  39
  40 void *
  41 _libelf_getphdr(Elf *e, int ec)
  42 {
  43         size_t phnum, phentsize;
  44         size_t fsz, msz;
  45         uint64_t phoff;
  46         Elf32_Ehdr *eh32;
  47         Elf64_Ehdr *eh64;
  48         void *ehdr, *phdr;
  49         int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap);
  50
  51         assert(ec == ELFCLASS32 || ec == ELFCLASS64);
  52
  53         if (e == NULL) {
  54                 LIBELF_SET_ERROR(ARGUMENT, 0);
  55                 return (NULL);
  56         }
  57
  58         if ((phdr = (ec == ELFCLASS32 ?
  59                  (void *) e->e_u.e_elf.e_phdr.e_phdr32 :
  60                  (void *) e->e_u.e_elf.e_phdr.e_phdr64)) != NULL)
  61                 return (phdr);
  62
  63         /*
  64          * Check the PHDR related fields in the EHDR for sanity.
  65          */
  66
  67         if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
  68                 return (NULL);
  69
  70         phnum = e->e_u.e_elf.e_nphdr;
  71
  72         if (ec == ELFCLASS32) {
  73                 eh32      = (Elf32_Ehdr *) ehdr;
  74                 phentsize = eh32->e_phentsize;
  75                 phoff     = (uint64_t) eh32->e_phoff;
  76         } else {
  77                 eh64      = (Elf64_Ehdr *) ehdr;
  78                 phentsize = eh64->e_phentsize;
  79                 phoff     = (uint64_t) eh64->e_phoff;
  80         }
  81
  82         fsz = gelf_fsize(e, ELF_T_PHDR, phnum, e->e_version);
  83
  84         assert(fsz > 0);
  85
  86         if ((uint64_t) e->e_rawsize < (phoff + fsz)) {
  87                 LIBELF_SET_ERROR(HEADER, 0);
  88                 return (NULL);
  89         }
  90
  91         msz = _libelf_msize(ELF_T_PHDR, ec, EV_CURRENT);
  92
  93         assert(msz > 0);
  94
  95         if ((phdr = calloc(phnum, msz)) == NULL) {
  96                 LIBELF_SET_ERROR(RESOURCE, 0);
  97                 return (NULL);
  98         }
  99
 100         if (ec == ELFCLASS32)
 101                 e->e_u.e_elf.e_phdr.e_phdr32 = phdr;
 102         else
 103                 e->e_u.e_elf.e_phdr.e_phdr64 = phdr;
 104
 105
 106         xlator = _libelf_get_translator(ELF_T_PHDR, ELF_TOMEMORY, ec);
 107         (*xlator)(phdr, phnum * msz, e->e_rawfile + phoff, phnum,
 108             e->e_byteorder != LIBELF_PRIVATE(byteorder));
 109
 110         return (phdr);
 111 }
 112
 113 void *
 114 _libelf_newphdr(Elf *e, int ec, size_t count)
 115 {
 116         void *ehdr, *newphdr, *oldphdr;
 117         size_t msz;
 118
 119         if (e == NULL) {
 120                 LIBELF_SET_ERROR(ARGUMENT, 0);
 121                 return (NULL);
 122         }
 123
 124         if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) {
 125                 LIBELF_SET_ERROR(SEQUENCE, 0);
 126                 return (NULL);
 127         }
 128
 129         assert(e->e_class == ec);
 130         assert(ec == ELFCLASS32 || ec == ELFCLASS64);
 131         assert(e->e_version == EV_CURRENT);
 132
 133         msz = _libelf_msize(ELF_T_PHDR, ec, e->e_version);
 134
 135         assert(msz > 0);
 136
 137         newphdr = NULL;
 138         if (count > 0 && (newphdr = calloc(count, msz)) == NULL) {
 139                 LIBELF_SET_ERROR(RESOURCE, 0);
 140                 return (NULL);
 141         }
 142
 143         if (ec == ELFCLASS32) {
 144                 if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr32) != NULL)
 145                         free(oldphdr);
 146                 e->e_u.e_elf.e_phdr.e_phdr32 = (Elf32_Phdr *) newphdr;
 147         } else {
 148                 if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr64) != NULL)
 149                         free(oldphdr);
 150                 e->e_u.e_elf.e_phdr.e_phdr64 = (Elf64_Phdr *) newphdr;
 151         }
 152
 153         e->e_u.e_elf.e_nphdr = count;
 154
 155         elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY);
 156
 157         return (newphdr);
 158 }