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  
 27  #include <sys/cdefs.h>
 28  
 29  #include <assert.h>
 30  #include <gelf.h>
 31  #include <limits.h>
 32  
 33  #include "_libelf.h"
 34  
 35  ELFTC_VCSID("$Id$");
 36  
 37  GElf_Dyn *
 38  gelf_getdyn(Elf_Data *ed, int ndx, GElf_Dyn *dst)
 39  {
 40  	int ec;
 41  	Elf *e;
 42  	size_t msz;
 43  	Elf_Scn *scn;
 44  	Elf32_Dyn *dyn32;
 45  	Elf64_Dyn *dyn64;
 46  	uint32_t sh_type;
 47  	struct _Libelf_Data *d;
 48  
 49  	d = (struct _Libelf_Data *) ed;
 50  
 51  	if (d == NULL || ndx < 0 || dst == NULL ||
 52  	    (scn = d->d_scn) == NULL ||
 53  	    (e = scn->s_elf) == NULL) {
 54  		LIBELF_SET_ERROR(ARGUMENT, 0);
 55  		return (NULL);
 56  	}
 57  
 58  	ec = e->e_class;
 59  	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
 60  
 61  	if (ec == ELFCLASS32)
 62  		sh_type = scn->s_shdr.s_shdr32.sh_type;
 63  	else
 64  		sh_type = scn->s_shdr.s_shdr64.sh_type;
 65  
 66  	if (_libelf_xlate_shtype(sh_type) != ELF_T_DYN) {
 67  		LIBELF_SET_ERROR(ARGUMENT, 0);
 68  		return (NULL);
 69  	}
 70  
 71  	msz = _libelf_msize(ELF_T_DYN, ec, e->e_version);
 72  
 73  	assert(msz > 0);
 74  	assert(ndx >= 0);
 75  
 76  	if (msz * (size_t) ndx >= d->d_data.d_size) {
 77  		LIBELF_SET_ERROR(ARGUMENT, 0);
 78  		return (NULL);
 79  	}
 80  
 81  	if (ec == ELFCLASS32) {
 82  		dyn32 = (Elf32_Dyn *) d->d_data.d_buf + ndx;
 83  
 84  		dst->d_tag      = dyn32->d_tag;
 85  		dst->d_un.d_val = (Elf64_Xword) dyn32->d_un.d_val;
 86  
 87  	} else {
 88  
 89  		dyn64 = (Elf64_Dyn *) d->d_data.d_buf + ndx;
 90  
 91  		*dst = *dyn64;
 92  	}
 93  
 94  	return (dst);
 95  }
 96  
 97  int
 98  gelf_update_dyn(Elf_Data *ed, int ndx, GElf_Dyn *ds)
 99  {
100  	int ec;
101  	Elf *e;
102  	size_t msz;
103  	Elf_Scn *scn;
104  	Elf32_Dyn *dyn32;
105  	Elf64_Dyn *dyn64;
106  	uint32_t sh_type;
107  	struct _Libelf_Data *d;
108  
109  	d = (struct _Libelf_Data *) ed;
110  
111  	if (d == NULL || ndx < 0 || ds == NULL ||
112  	    (scn = d->d_scn) == NULL ||
113  	    (e = scn->s_elf) == NULL) {
114  		LIBELF_SET_ERROR(ARGUMENT, 0);
115  		return (0);
116  	}
117  
118  	ec = e->e_class;
119  	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
120  
121  	if (ec == ELFCLASS32)
122  		sh_type = scn->s_shdr.s_shdr32.sh_type;
123  	else
124  		sh_type = scn->s_shdr.s_shdr64.sh_type;
125  
126  	if (_libelf_xlate_shtype(sh_type) != ELF_T_DYN) {
127  		LIBELF_SET_ERROR(ARGUMENT, 0);
128  		return (0);
129  	}
130  
131  	msz = _libelf_msize(ELF_T_DYN, ec, e->e_version);
132  
133  	assert(msz > 0);
134  	assert(ndx >= 0);
135  
136  	if (msz * (size_t) ndx >= d->d_data.d_size) {
137  		LIBELF_SET_ERROR(ARGUMENT, 0);
138  		return (0);
139  	}
140  
141  	if (ec == ELFCLASS32) {
142  		dyn32 = (Elf32_Dyn *) d->d_data.d_buf + ndx;
143  
144  		LIBELF_COPY_S32(dyn32, ds, d_tag);
145  		LIBELF_COPY_U32(dyn32, ds, d_un.d_val);
146  	} else {
147  		dyn64 = (Elf64_Dyn *) d->d_data.d_buf + ndx;
148  
149  		*dyn64 = *ds;
150  	}
151  
152  	return (1);
153  }