1// binary.cc -- binary input files for gold
2
3// Copyright 2008 Free Software Foundation, Inc.
4// Written by Ian Lance Taylor <iant@google.com>.
5
6// This file is part of gold.
7
8// This program is free software; you can redistribute it and/or modify
9// it under the terms of the GNU General Public License as published by
10// the Free Software Foundation; either version 3 of the License, or
11// (at your option) any later version.
12
13// This program is distributed in the hope that it will be useful,
14// but WITHOUT ANY WARRANTY; without even the implied warranty of
15// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16// GNU General Public License for more details.
17
18// You should have received a copy of the GNU General Public License
19// along with this program; if not, write to the Free Software
20// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21// MA 02110-1301, USA.
22
23#include "gold.h"
24
25#include <cerrno>
26#include <cstring>
27#include "safe-ctype.h"
28
29#include "elfcpp.h"
30#include "stringpool.h"
31#include "fileread.h"
32#include "output.h"
33#include "binary.h"
34
35// Support for reading binary files as input.  These become blobs in
36// the final output.  These files are treated as though they have a
37// single .data section and define three symbols:
38// _binary_FILENAME_start, _binary_FILENAME_end, _binary_FILENAME_size.
39// The FILENAME is the name of the input file, with any
40// non-alphanumeric character changed to an underscore.
41
42// We implement this by creating an ELF file in memory.
43
44namespace gold
45{
46
47// class Binary_to_elf.
48
49Binary_to_elf::Binary_to_elf(elfcpp::EM machine, int size, bool big_endian,
50			     const std::string& filename)
51  : elf_machine_(machine), size_(size), big_endian_(big_endian),
52    filename_(filename), data_(NULL), filesize_(0)
53{
54}
55
56Binary_to_elf::~Binary_to_elf()
57{
58  if (this->data_ != NULL)
59    delete[] this->data_;
60}
61
62// Given FILENAME, create a buffer which looks like an ELF file with
63// the contents of FILENAME as the contents of the only section.  The
64// TASK parameters is mainly for debugging, and records who holds
65// locks.
66
67bool
68Binary_to_elf::convert(const Task* task)
69{
70  if (this->size_ == 32)
71    {
72      if (!this->big_endian_)
73	{
74#ifdef HAVE_TARGET_32_LITTLE
75	  return this->sized_convert<32, false>(task);
76#else
77	  gold_unreachable();
78#endif
79	}
80      else
81	{
82#ifdef HAVE_TARGET_32_BIG
83	  return this->sized_convert<32, true>(task);
84#else
85	  gold_unreachable();
86#endif
87	}
88    }
89  else if (this->size_ == 64)
90    {
91      if (!this->big_endian_)
92	{
93#ifdef HAVE_TARGET_64_LITTLE
94	  return this->sized_convert<64, false>(task);
95#else
96	  gold_unreachable();
97#endif
98	}
99      else
100	{
101#ifdef HAVE_TARGET_64_BIG
102	  return this->sized_convert<64, true>(task);
103#else
104	  gold_unreachable();
105#endif
106	}
107    }
108  else
109    gold_unreachable();
110}
111
112// We are going to create:
113// * The ELF file header.
114// * Five sections: null section, .data, .symtab, .strtab, .shstrtab
115// * The contents of the file.
116// * Four symbols: null, begin, end, size.
117// * Three symbol names.
118// * Four section names.
119
120template<int size, bool big_endian>
121bool
122Binary_to_elf::sized_convert(const Task* task)
123{
124  // Read the input file.
125
126  File_read f;
127  if (!f.open(task, this->filename_))
128    {
129      gold_error(_("cannot open %s: %s:"), this->filename_.c_str(),
130		 strerror(errno));
131      return false;
132    }
133
134  section_size_type filesize = convert_to_section_size_type(f.filesize());
135  const unsigned char* fileview;
136  if (filesize == 0)
137    fileview = NULL;
138  else
139    fileview = f.get_view(0, 0, filesize, false, false);
140
141  unsigned int align;
142  if (size == 32)
143    align = 4;
144  else if (size == 64)
145    align = 8;
146  else
147    gold_unreachable();
148  section_size_type aligned_filesize = align_address(filesize, align);
149
150  // Build the stringpool for the symbol table.
151
152  std::string mangled_name = this->filename_;
153  for (std::string::iterator p = mangled_name.begin();
154       p != mangled_name.end();
155       ++p)
156    if (!ISALNUM(*p))
157      *p = '_';
158  mangled_name = "_binary_" + mangled_name;
159  std::string start_symbol_name = mangled_name + "_start";
160  std::string end_symbol_name = mangled_name + "_end";
161  std::string size_symbol_name = mangled_name + "_size";
162
163  Stringpool strtab;
164  strtab.add(start_symbol_name.c_str(), false, NULL);
165  strtab.add(end_symbol_name.c_str(), false, NULL);
166  strtab.add(size_symbol_name.c_str(), false, NULL);
167  strtab.set_string_offsets();
168
169  // Build the stringpool for the section name table.
170
171  Stringpool shstrtab;
172  shstrtab.add(".data", false, NULL);
173  shstrtab.add(".symtab", false, NULL);
174  shstrtab.add(".strtab", false, NULL);
175  shstrtab.add(".shstrtab", false, NULL);
176  shstrtab.set_string_offsets();
177
178  // Work out the size of the generated file, and the offsets of the
179  // various sections, and allocate a buffer.
180
181  const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
182
183  size_t output_size = (elfcpp::Elf_sizes<size>::ehdr_size
184			+ 5 * elfcpp::Elf_sizes<size>::shdr_size);
185  size_t data_offset = output_size;
186  output_size += aligned_filesize;
187  size_t symtab_offset = output_size;
188  output_size += 4 * sym_size;
189  size_t strtab_offset = output_size;
190  output_size += strtab.get_strtab_size();
191  size_t shstrtab_offset = output_size;
192  output_size += shstrtab.get_strtab_size();
193
194  unsigned char* buffer = new unsigned char[output_size];
195
196  // Write out the data.
197
198  unsigned char* pout = buffer;
199
200  this->write_file_header<size, big_endian>(&pout);
201
202  this->write_section_header<size, big_endian>("", &shstrtab, elfcpp::SHT_NULL,
203					       0, 0, 0, 0, 0,
204					       0, 0, &pout);
205  // Having the section be named ".data", having it be writable, and
206  // giving it an alignment of 1 is because the GNU linker does it
207  // that way, and existing linker script expect it.
208  this->write_section_header<size, big_endian>(".data", &shstrtab,
209					       elfcpp::SHT_PROGBITS,
210					       (elfcpp::SHF_ALLOC
211						| elfcpp::SHF_WRITE),
212					       data_offset,
213					       filesize, 0, 0,
214					       1, 0, &pout);
215  this->write_section_header<size, big_endian>(".symtab", &shstrtab,
216					       elfcpp::SHT_SYMTAB,
217					       0, symtab_offset, 4 * sym_size,
218					       3, 1, align, sym_size, &pout);
219  this->write_section_header<size, big_endian>(".strtab", &shstrtab,
220					       elfcpp::SHT_STRTAB,
221					       0, strtab_offset,
222					       strtab.get_strtab_size(),
223					       0, 0, 1, 0, &pout);
224  this->write_section_header<size, big_endian>(".shstrtab", &shstrtab,
225					       elfcpp::SHT_STRTAB,
226					       0, shstrtab_offset,
227					       shstrtab.get_strtab_size(),
228					       0, 0, 1, 0, &pout);
229
230  if (filesize > 0)
231    {
232      memcpy(pout, fileview, filesize);
233      pout += filesize;
234      memset(pout, 0, aligned_filesize - filesize);
235      pout += aligned_filesize - filesize;
236    }
237
238  this->write_symbol<size, big_endian>("", &strtab, 0, 0, &pout);
239  this->write_symbol<size, big_endian>(start_symbol_name, &strtab, 0, 1,
240				       &pout);
241  this->write_symbol<size, big_endian>(end_symbol_name, &strtab, filesize, 1,
242				       &pout);
243  this->write_symbol<size, big_endian>(size_symbol_name, &strtab, filesize,
244				       elfcpp::SHN_ABS, &pout);
245
246  strtab.write_to_buffer(pout, strtab.get_strtab_size());
247  pout += strtab.get_strtab_size();
248
249  shstrtab.write_to_buffer(pout, shstrtab.get_strtab_size());
250  pout += shstrtab.get_strtab_size();
251
252  gold_assert(static_cast<size_t>(pout - buffer) == output_size);
253
254  this->data_ = buffer;
255  this->filesize_ = output_size;
256
257  f.unlock(task);
258
259  return true;
260}
261
262// Write out the file header.
263
264template<int size, bool big_endian>
265void
266Binary_to_elf::write_file_header(unsigned char** ppout)
267{
268  elfcpp::Ehdr_write<size, big_endian> oehdr(*ppout);
269
270  unsigned char e_ident[elfcpp::EI_NIDENT];
271  memset(e_ident, 0, elfcpp::EI_NIDENT);
272  e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0;
273  e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1;
274  e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2;
275  e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3;
276  if (size == 32)
277    e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32;
278  else if (size == 64)
279    e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64;
280  else
281    gold_unreachable();
282  e_ident[elfcpp::EI_DATA] = (big_endian
283			      ? elfcpp::ELFDATA2MSB
284			      : elfcpp::ELFDATA2LSB);
285  e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT;
286  oehdr.put_e_ident(e_ident);
287
288  oehdr.put_e_type(elfcpp::ET_REL);
289  oehdr.put_e_machine(this->elf_machine_);
290  oehdr.put_e_version(elfcpp::EV_CURRENT);
291  oehdr.put_e_entry(0);
292  oehdr.put_e_phoff(0);
293  oehdr.put_e_shoff(elfcpp::Elf_sizes<size>::ehdr_size);
294  oehdr.put_e_flags(0);
295  oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size);
296  oehdr.put_e_phentsize(0);
297  oehdr.put_e_phnum(0);
298  oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size);
299  oehdr.put_e_shnum(5);
300  oehdr.put_e_shstrndx(4);
301
302  *ppout += elfcpp::Elf_sizes<size>::ehdr_size;
303}
304
305// Write out a section header.
306
307template<int size, bool big_endian>
308void
309Binary_to_elf::write_section_header(
310    const char* name,
311    const Stringpool* shstrtab,
312    elfcpp::SHT type,
313    unsigned int flags,
314    section_size_type offset,
315    section_size_type section_size,
316    unsigned int link,
317    unsigned int info,
318    unsigned int addralign,
319    unsigned int entsize,
320    unsigned char** ppout)
321{
322  elfcpp::Shdr_write<size, big_endian> oshdr(*ppout);
323
324  oshdr.put_sh_name(*name == '\0' ? 0 : shstrtab->get_offset(name));
325  oshdr.put_sh_type(type);
326  oshdr.put_sh_flags(flags);
327  oshdr.put_sh_addr(0);
328  oshdr.put_sh_offset(offset);
329  oshdr.put_sh_size(section_size);
330  oshdr.put_sh_link(link);
331  oshdr.put_sh_info(info);
332  oshdr.put_sh_addralign(addralign);
333  oshdr.put_sh_entsize(entsize);
334
335  *ppout += elfcpp::Elf_sizes<size>::shdr_size;
336}
337
338// Write out a symbol.
339
340template<int size, bool big_endian>
341void
342Binary_to_elf::write_symbol(
343    const std::string& name,
344    const Stringpool* strtab,
345    section_size_type value,
346    unsigned int shndx,
347    unsigned char** ppout)
348{
349  unsigned char* pout = *ppout;
350
351  elfcpp::Sym_write<size, big_endian> osym(pout);
352  osym.put_st_name(name.empty() ? 0 : strtab->get_offset(name.c_str()));
353  osym.put_st_value(value);
354  osym.put_st_size(0);
355  osym.put_st_info(name.empty() ? elfcpp::STB_LOCAL : elfcpp::STB_GLOBAL,
356		   elfcpp::STT_NOTYPE);
357  osym.put_st_other(elfcpp::STV_DEFAULT, 0);
358  osym.put_st_shndx(shndx);
359
360  *ppout += elfcpp::Elf_sizes<size>::sym_size;
361}
362
363} // End namespace gold.
364