ext/libelf/libelf_phdr.c

   1 /*-
   2  * Copyright (c) 2006 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 <assert.h>
  30 #include <stdlib.h>
  31
  32 #include "gelf.h"
  33 #include "libelf.h"
  34 #include "_libelf.h"
  35
  36 void *
  37 _libelf_getphdr(Elf *e, int ec)
  38 {
  39         size_t phnum, phentsize;
  40         size_t fsz, msz;
  41         uint64_t phoff;
  42         Elf32_Ehdr *eh32;
  43         Elf64_Ehdr *eh64;
  44         void *ehdr, *phdr;
  45         void (*xlator)(char *_d, char *_s, size_t _c, int _swap);
  46
  47         assert(ec == ELFCLASS32 || ec == ELFCLASS64);
  48
  49         if (e == NULL) {
  50                 LIBELF_SET_ERROR(ARGUMENT, 0);
  51                 return (NULL);
  52         }
  53
  54         if ((phdr = (ec == ELFCLASS32 ?
  55                  (void *) e->e_u.e_elf.e_phdr.e_phdr32 :
  56                  (void *) e->e_u.e_elf.e_phdr.e_phdr64)) != NULL)
  57                 return (phdr);
  58
  59         /*
  60          * Check the PHDR related fields in the EHDR for sanity.
  61          */
  62
  63         if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
  64                 return (NULL);
  65
  66         phnum = e->e_u.e_elf.e_nphdr;
  67
  68         if (ec == ELFCLASS32) {
  69                 eh32      = (Elf32_Ehdr *) ehdr;
  70                 phentsize = eh32->e_phentsize;
  71                 phoff     = (uint64_t) eh32->e_phoff;
  72         } else {
  73                 eh64      = (Elf64_Ehdr *) ehdr;
  74                 phentsize = eh64->e_phentsize;
  75                 phoff     = (uint64_t) eh64->e_phoff;
  76         }
  77
  78         fsz = gelf_fsize(e, ELF_T_PHDR, phnum, e->e_version);
  79
  80         assert(fsz > 0);
  81
  82         if ((uint64_t) e->e_rawsize < (phoff + fsz)) {
  83                 LIBELF_SET_ERROR(HEADER, 0);
  84                 return (NULL);
  85         }
  86
  87         msz = _libelf_msize(ELF_T_PHDR, ec, EV_CURRENT);
  88
  89         assert(msz > 0);
  90
  91         if ((phdr = calloc(phnum, msz)) == NULL) {
  92                 LIBELF_SET_ERROR(RESOURCE, 0);
  93                 return (NULL);
  94         }
  95
  96         if (ec == ELFCLASS32)
  97                 e->e_u.e_elf.e_phdr.e_phdr32 = phdr;
  98         else
  99                 e->e_u.e_elf.e_phdr.e_phdr64 = phdr;
 100
 101
 102         xlator = _libelf_get_translator(ELF_T_PHDR, ELF_TOMEMORY, ec);
 103         (*xlator)(phdr, e->e_rawfile + phoff, phnum,
 104             e->e_byteorder != LIBELF_PRIVATE(byteorder));
 105
 106         return (phdr);
 107 }
 108
 109 void *
 110 _libelf_newphdr(Elf *e, int ec, size_t count)
 111 {
 112         void *ehdr, *newphdr, *oldphdr;
 113         size_t msz;
 114
 115         if (e == NULL) {
 116                 LIBELF_SET_ERROR(ARGUMENT, 0);
 117                 return (NULL);
 118         }
 119
 120         if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) {
 121                 LIBELF_SET_ERROR(SEQUENCE, 0);
 122                 return (NULL);
 123         }
 124
 125         assert(e->e_class == ec);
 126         assert(ec == ELFCLASS32 || ec == ELFCLASS64);
 127         assert(e->e_version == EV_CURRENT);
 128
 129         msz = _libelf_msize(ELF_T_PHDR, ec, e->e_version);
 130
 131         assert(msz > 0);
 132
 133         newphdr = NULL;
 134         if (count > 0 && (newphdr = calloc(count, msz)) == NULL) {
 135                 LIBELF_SET_ERROR(RESOURCE, 0);
 136                 return (NULL);
 137         }
 138
 139         if (ec == ELFCLASS32) {
 140                 if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr32) != NULL)
 141                         free(oldphdr);
 142                 e->e_u.e_elf.e_phdr.e_phdr32 = (Elf32_Phdr *) newphdr;
 143         } else {
 144                 if ((oldphdr = (void *) e->e_u.e_elf.e_phdr.e_phdr64) != NULL)
 145                         free(oldphdr);
 146                 e->e_u.e_elf.e_phdr.e_phdr64 = (Elf64_Phdr *) newphdr;
 147         }
 148
 149         e->e_u.e_elf.e_nphdr = count;
 150
 151         elf_flagphdr(e, ELF_C_SET, ELF_F_DIRTY);
 152
 153         return (newphdr);
 154 }