aboutsummaryrefslogtreecommitdiff
path: root/bfd/elf.c
blob: 224eaacc4709491512e7ade180c53debf3294b6a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
/* ELF executable support for BFD.
   Copyright 1993 Free Software Foundation, Inc.

This file is part of BFD, the Binary File Descriptor library.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "bfd.h"
#include "sysdep.h"
#include "libbfd.h"
#define ARCH_SIZE 0
#include "libelf.h"

#ifndef INLINE
#if __GNUC__ >= 2
#define INLINE __inline__
#else
#define INLINE
#endif
#endif

/* Standard ELF hash function.  Do not change this function; you will
   cause invalid hash tables to be generated.  (Well, you would if this
   were being used yet.)  */
unsigned long
DEFUN (bfd_elf_hash, (name),
       CONST unsigned char *name)
{
  unsigned long h = 0;
  unsigned long g;
  int ch;

  while ((ch = *name++) != '\0')
    {
      h = (h << 4) + ch;
      if ((g = (h & 0xf0000000)) != 0)
	{
	  h ^= g >> 24;
	  h &= ~g;
	}
    }
  return h;
}

/* Read a specified number of bytes at a specified offset in an ELF
   file, into a newly allocated buffer, and return a pointer to the
   buffer. */

static char *
DEFUN (elf_read, (abfd, offset, size),
       bfd * abfd AND
       long offset AND
       int size)
{
  char *buf;

  if ((buf = bfd_alloc (abfd, size)) == NULL)
    {
      bfd_error = no_memory;
      return NULL;
    }
  if (bfd_seek (abfd, offset, SEEK_SET) == -1)
    {
      bfd_error = system_call_error;
      return NULL;
    }
  if (bfd_read ((PTR) buf, size, 1, abfd) != size)
    {
      bfd_error = system_call_error;
      return NULL;
    }
  return buf;
}

boolean
DEFUN (elf_mkobject, (abfd), bfd * abfd)
{
  /* this just does initialization */
  /* coff_mkobject zalloc's space for tdata.coff_obj_data ... */
  elf_tdata (abfd) = (struct elf_obj_tdata *)
    bfd_zalloc (abfd, sizeof (struct elf_obj_tdata));
  if (elf_tdata (abfd) == 0)
    {
      bfd_error = no_memory;
      return false;
    }
  /* since everything is done at close time, do we need any
     initialization? */

  return true;
}

char *
DEFUN (elf_get_str_section, (abfd, shindex),
       bfd * abfd AND
       unsigned int shindex)
{
  Elf_Internal_Shdr **i_shdrp;
  char *shstrtab = NULL;
  unsigned int offset;
  unsigned int shstrtabsize;

  i_shdrp = elf_elfsections (abfd);
  if (i_shdrp == 0 || i_shdrp[shindex] == 0)
    return 0;

  shstrtab = i_shdrp[shindex]->rawdata;
  if (shstrtab == NULL)
    {
      /* No cached one, attempt to read, and cache what we read. */
      offset = i_shdrp[shindex]->sh_offset;
      shstrtabsize = i_shdrp[shindex]->sh_size;
      shstrtab = elf_read (abfd, offset, shstrtabsize);
      i_shdrp[shindex]->rawdata = (void *) shstrtab;
    }
  return shstrtab;
}

char *
DEFUN (elf_string_from_elf_section, (abfd, shindex, strindex),
       bfd * abfd AND
       unsigned int shindex AND
       unsigned int strindex)
{
  Elf_Internal_Shdr *hdr;

  if (strindex == 0)
    return "";

  hdr = elf_elfsections (abfd)[shindex];

  if (!hdr->rawdata
      && elf_get_str_section (abfd, shindex) == NULL)
    return NULL;

  return ((char *) hdr->rawdata) + strindex;
}

/*
INTERNAL_FUNCTION
	bfd_elf_find_section

SYNOPSIS
	struct elf_internal_shdr *bfd_elf_find_section (bfd *abfd, char *name);

DESCRIPTION
	Helper functions for GDB to locate the string tables.
	Since BFD hides string tables from callers, GDB needs to use an
	internal hook to find them.  Sun's .stabstr, in particular,
	isn't even pointed to by the .stab section, so ordinary
	mechanisms wouldn't work to find it, even if we had some.
*/

struct elf_internal_shdr *
DEFUN (bfd_elf_find_section, (abfd, name),
       bfd * abfd AND
       char *name)
{
  Elf_Internal_Shdr **i_shdrp;
  char *shstrtab;
  unsigned int max;
  unsigned int i;

  i_shdrp = elf_elfsections (abfd);
  if (i_shdrp != NULL)
    {
      shstrtab = elf_get_str_section (abfd, elf_elfheader (abfd)->e_shstrndx);
      if (shstrtab != NULL)
	{
	  max = elf_elfheader (abfd)->e_shnum;
	  for (i = 1; i < max; i++)
	    if (!strcmp (&shstrtab[i_shdrp[i]->sh_name], name))
	      return i_shdrp[i];
	}
    }
  return 0;
}

const struct bfd_elf_arch_map bfd_elf_arch_map[] = {
  { bfd_arch_sparc, EM_SPARC },
  { bfd_arch_i386, EM_386 },
  { bfd_arch_m68k, EM_68K },
  { bfd_arch_m88k, EM_88K },
  { bfd_arch_i860, EM_860 },
  { bfd_arch_mips, EM_MIPS },
  { bfd_arch_hppa, EM_HPPA },
};

const int bfd_elf_arch_map_size = sizeof (bfd_elf_arch_map) / sizeof (bfd_elf_arch_map[0]);

const char *const bfd_elf_section_type_names[] = {
  "SHT_NULL", "SHT_PROGBITS", "SHT_SYMTAB", "SHT_STRTAB",
  "SHT_RELA", "SHT_HASH", "SHT_DYNAMIC", "SHT_NOTE",
  "SHT_NOBITS", "SHT_REL", "SHT_SHLIB", "SHT_DYNSYM",
};

/* ELF relocs are against symbols.  If we are producing relocateable
   output, and the reloc is against an external symbol, and nothing
   has given us any additional addend, the resulting reloc will also
   be against the same symbol.  In such a case, we don't want to
   change anything about the way the reloc is handled, since it will
   all be done at final link time.  Rather than put special case code
   into bfd_perform_relocation, all the reloc types use this howto
   function.  It just short circuits the reloc if producing
   relocateable output against an external symbol.  */

bfd_reloc_status_type
bfd_elf_generic_reloc (abfd,
		       reloc_entry,
		       symbol,
		       data,
		       input_section,
		       output_bfd)
     bfd *abfd;
     arelent *reloc_entry;
     asymbol *symbol;
     PTR data;
     asection *input_section;
     bfd *output_bfd;
{
  if (output_bfd != (bfd *) NULL
      && (symbol->flags & BSF_SECTION_SYM) == 0
      && reloc_entry->addend == 0)
    {
      reloc_entry->address += input_section->output_offset;
      return bfd_reloc_ok;
    }

  return bfd_reloc_continue;
}