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_Sym *
 38  gelf_getsym(Elf_Data *ed, int ndx, GElf_Sym *dst)
 39  {
 40  	int ec;
 41  	Elf *e;
 42  	size_t msz;
 43  	Elf_Scn *scn;
 44  	uint32_t sh_type;
 45  	Elf32_Sym *sym32;
 46  	Elf64_Sym *sym64;
 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_SYM) {
 67  		LIBELF_SET_ERROR(ARGUMENT, 0);
 68  		return (NULL);
 69  	}
 70  
 71  	msz = _libelf_msize(ELF_T_SYM, 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  		sym32 = (Elf32_Sym *) d->d_data.d_buf + ndx;
 83  
 84  		dst->st_name  = sym32->st_name;
 85  		dst->st_value = (Elf64_Addr) sym32->st_value;
 86  		dst->st_size  = (Elf64_Xword) sym32->st_size;
 87  		dst->st_info  = sym32->st_info;
 88  		dst->st_other = sym32->st_other;
 89  		dst->st_shndx = sym32->st_shndx;
 90  	} else {
 91  		sym64 = (Elf64_Sym *) d->d_data.d_buf + ndx;
 92  
 93  		*dst = *sym64;
 94  	}
 95  
 96  	return (dst);
 97  }
 98  
 99  int
100  gelf_update_sym(Elf_Data *ed, int ndx, GElf_Sym *gs)
101  {
102  	int ec;
103  	Elf *e;
104  	size_t msz;
105  	Elf_Scn *scn;
106  	uint32_t sh_type;
107  	Elf32_Sym *sym32;
108  	Elf64_Sym *sym64;
109  	struct _Libelf_Data *d;
110  
111  	d = (struct _Libelf_Data *) ed;
112  
113  	if (d == NULL || ndx < 0 || gs == NULL ||
114  	    (scn = d->d_scn) == NULL ||
115  	    (e = scn->s_elf) == NULL) {
116  		LIBELF_SET_ERROR(ARGUMENT, 0);
117  		return (0);
118  	}
119  
120  	ec = e->e_class;
121  	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
122  
123  	if (ec == ELFCLASS32)
124  		sh_type = scn->s_shdr.s_shdr32.sh_type;
125  	else
126  		sh_type = scn->s_shdr.s_shdr64.sh_type;
127  
128  	if (_libelf_xlate_shtype(sh_type) != ELF_T_SYM) {
129  		LIBELF_SET_ERROR(ARGUMENT, 0);
130  		return (0);
131  	}
132  
133  	msz = _libelf_msize(ELF_T_SYM, ec, e->e_version);
134  
135  	assert(msz > 0);
136  	assert(ndx >= 0);
137  
138  	if (msz * (size_t) ndx >= d->d_data.d_size) {
139  		LIBELF_SET_ERROR(ARGUMENT, 0);
140  		return (0);
141  	}
142  
143  	if (ec == ELFCLASS32) {
144  		sym32 = (Elf32_Sym *) d->d_data.d_buf + ndx;
145  
146  		sym32->st_name  = gs->st_name;
147  		sym32->st_info  = gs->st_info;
148  		sym32->st_other = gs->st_other;
149  		sym32->st_shndx = gs->st_shndx;
150  
151  		LIBELF_COPY_U32(sym32, gs, st_value);
152  		LIBELF_COPY_U32(sym32, gs, st_size);
153  	} else {
154  		sym64 = (Elf64_Sym *) d->d_data.d_buf + ndx;
155  
156  		*sym64 = *gs;
157  	}
158  
159  	return (1);
160  }