ext/libelf/gelf_dyn.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
  27 #include <assert.h>
  28 #include <limits.h>
  29
  30 #include "gelf.h"
  31 #include "_libelf.h"
  32
  33 GElf_Dyn *
  34 gelf_getdyn(Elf_Data *d, int ndx, GElf_Dyn *dst)
  35 {
  36         int ec;
  37         Elf *e;
  38         Elf_Scn *scn;
  39         Elf32_Dyn *dyn32;
  40         Elf64_Dyn *dyn64;
  41         size_t msz;
  42         uint32_t sh_type;
  43
  44         if (d == NULL || ndx < 0 || dst == NULL ||
  45             (scn = d->d_scn) == NULL ||
  46             (e = scn->s_elf) == NULL) {
  47                 LIBELF_SET_ERROR(ARGUMENT, 0);
  48                 return (NULL);
  49         }
  50
  51         ec = e->e_class;
  52         assert(ec == ELFCLASS32 || ec == ELFCLASS64);
  53
  54         if (ec == ELFCLASS32)
  55                 sh_type = scn->s_shdr.s_shdr32.sh_type;
  56         else
  57                 sh_type = scn->s_shdr.s_shdr64.sh_type;
  58
  59         if (_libelf_xlate_shtype(sh_type) != ELF_T_DYN) {
  60                 LIBELF_SET_ERROR(ARGUMENT, 0);
  61                 return (NULL);
  62         }
  63
  64         msz = _libelf_msize(ELF_T_DYN, ec, e->e_version);
  65
  66         assert(msz > 0);
  67
  68         if (msz * ndx >= d->d_size) {
  69                 LIBELF_SET_ERROR(ARGUMENT, 0);
  70                 return (NULL);
  71         }
  72
  73         if (ec == ELFCLASS32) {
  74                 dyn32 = (Elf32_Dyn *) d->d_buf + ndx;
  75
  76                 dst->d_tag      = dyn32->d_tag;
  77                 dst->d_un.d_val = (Elf64_Xword) dyn32->d_un.d_val;
  78
  79         } else {
  80
  81                 dyn64 = (Elf64_Dyn *) d->d_buf + ndx;
  82
  83                 *dst = *dyn64;
  84         }
  85
  86         return (dst);
  87 }
  88
  89 int
  90 gelf_update_dyn(Elf_Data *d, int ndx, GElf_Dyn *ds)
  91 {
  92         int ec;
  93         Elf *e;
  94         Elf_Scn *scn;
  95         Elf32_Dyn *dyn32;
  96         Elf64_Dyn *dyn64;
  97         size_t msz;
  98         uint32_t sh_type;
  99
 100         if (d == NULL || ndx < 0 || ds == NULL ||
 101             (scn = d->d_scn) == NULL ||
 102             (e = scn->s_elf) == NULL) {
 103                 LIBELF_SET_ERROR(ARGUMENT, 0);
 104                 return (0);
 105         }
 106
 107         ec = e->e_class;
 108         assert(ec == ELFCLASS32 || ec == ELFCLASS64);
 109
 110         if (ec == ELFCLASS32)
 111                 sh_type = scn->s_shdr.s_shdr32.sh_type;
 112         else
 113                 sh_type = scn->s_shdr.s_shdr64.sh_type;
 114
 115         if (_libelf_xlate_shtype(sh_type) != ELF_T_DYN) {
 116                 LIBELF_SET_ERROR(ARGUMENT, 0);
 117                 return (0);
 118         }
 119
 120         msz = _libelf_msize(ELF_T_DYN, ec, e->e_version);
 121         assert(msz > 0);
 122
 123         if (msz * ndx >= d->d_size) {
 124                 LIBELF_SET_ERROR(ARGUMENT, 0);
 125                 return (0);
 126         }
 127
 128         if (ec == ELFCLASS32) {
 129                 dyn32 = (Elf32_Dyn *) d->d_buf + ndx;
 130
 131                 LIBELF_COPY_S32(dyn32, ds, d_tag);
 132                 LIBELF_COPY_U32(dyn32, ds, d_un.d_val);
 133         } else {
 134                 dyn64 = (Elf64_Dyn *) d->d_buf + ndx;
 135
 136                 *dyn64 = *ds;
 137         }
 138
 139         return (1);
 140 }