aboutsummaryrefslogtreecommitdiff
path: root/gold/archive.cc
blob: 031ead09a408fc1f82d1681838b0965675d0ef45 (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
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
// archive.cc -- archive support for gold

#include "gold.h"

#include <cerrno>
#include <cstring>
#include <climits>
#include <vector>

#include "elfcpp.h"
#include "fileread.h"
#include "readsyms.h"
#include "symtab.h"
#include "object.h"
#include "archive.h"

namespace gold
{

// The header of an entry in the archive.  This is all readable text,
// padded with spaces where necesary.  If the contents of an archive
// are all text file, the entire archive is readable.

struct Archive::Archive_header
{
  // The entry name.
  char ar_name[16];
  // The file modification time.
  char ar_date[12];
  // The user's UID in decimal.
  char ar_uid[6];
  // The user's GID in decimal.
  char ar_gid[6];
  // The file mode in octal.
  char ar_mode[8];
  // The file size in decimal.
  char ar_size[10];
  // The final magic code.
  char ar_fmag[2];
};

// Archive methods.

const char Archive::armag[sarmag] =
{
  '!', '<', 'a', 'r', 'c', 'h', '>', '\n'
};

const char Archive::arfmag[2] = { '`', '\n' };

// Set up the archive: read the symbol map and the extended name
// table.

void
Archive::setup()
{
  // The first member of the archive should be the symbol table.
  std::string armap_name;
  off_t armap_size = this->read_header(sarmag, &armap_name);
  if (!armap_name.empty())
    {
      fprintf(stderr, _("%s: %s: no archive symbol table (run ranlib)\n"),
	      program_name, this->name().c_str());
      gold_exit(false);
    }

  // Read in the entire armap.
  const unsigned char* p = this->get_view(sarmag + sizeof(Archive_header),
					  armap_size);

  // Numbers in the armap are always big-endian.
  const elfcpp::Elf_Word* pword = reinterpret_cast<const elfcpp::Elf_Word*>(p);
  unsigned int nsyms = elfcpp::read_elf_word<true>(pword);
  ++pword;

  // Note that the addition is in units of sizeof(elfcpp::Elf_Word).
  const char* pnames = reinterpret_cast<const char*>(pword + nsyms);

  this->armap_.resize(nsyms);

  for (unsigned int i = 0; i < nsyms; ++i)
    {
      this->armap_[i].name = pnames;
      this->armap_[i].offset = elfcpp::read_elf_word<true>(pword);
      pnames += strlen(pnames) + 1;
      ++pword;
    }

  if (reinterpret_cast<const unsigned char*>(pnames) - p > armap_size)
    {
      fprintf(stderr, _("%s: %s: bad archive symbol table names\n"),
	      program_name, this->name().c_str());
      gold_exit(false);
    }

  // See if there is an extended name table.
  off_t off = sarmag + sizeof(Archive_header) + armap_size;
  if ((off & 1) != 0)
    ++off;
  std::string xname;
  off_t extended_size = this->read_header(off, &xname);
  if (xname == "/")
    {
      p = this->get_view(off + sizeof(Archive_header), extended_size);
      const char* px = reinterpret_cast<const char*>(p);
      this->extended_names_.assign(px, extended_size);
    }

  // This array keeps track of which symbols are for archive elements
  // which we have already included in the link.
  this->seen_.resize(nsyms);

  // Opening the file locked it.  Unlock it now.
  this->input_file_->file().unlock();
}

// Read the header of an archive member at OFF.  Fail if something
// goes wrong.  Return the size of the member.  Set *PNAME to the name
// of the member.

off_t
Archive::read_header(off_t off, std::string* pname)
{
  const unsigned char* p = this->get_view(off, sizeof(Archive_header));
  const Archive_header* hdr = reinterpret_cast<const Archive_header*>(p);

  if (memcmp(hdr->ar_fmag, arfmag, sizeof arfmag) != 0)
    {
      fprintf(stderr, _("%s; %s: malformed archive header at %ld\n"),
	      program_name, this->name().c_str(),
	      static_cast<long>(off));
      gold_exit(false);
    }

  const int size_string_size = sizeof hdr->ar_size;
  char size_string[size_string_size + 1];
  memcpy(size_string, hdr->ar_size, size_string_size);
  char* ps = size_string + size_string_size;
  while (ps[-1] == ' ')
    --ps;
  *ps = '\0';

  errno = 0;
  char* end;
  off_t member_size = strtol(size_string, &end, 10);
  if (*end != '\0'
      || member_size < 0
      || (member_size == LONG_MAX && errno == ERANGE))
    {
      fprintf(stderr, _("%s: %s: malformed archive header size at %ld\n"),
	      program_name, this->name().c_str(),
	      static_cast<long>(off));
      gold_exit(false);
    }

  if (hdr->ar_name[0] != '/')
    {
      const char* name_end = strchr(hdr->ar_name, '/');
      if (name_end == NULL
	  || name_end - hdr->ar_name >= static_cast<int>(sizeof hdr->ar_name))
	{
	  fprintf(stderr, _("%s: %s: malformed archive header name at %ld\n"),
		  program_name, this->name().c_str(),
		  static_cast<long>(off));
	  gold_exit(false);
	}
      pname->assign(hdr->ar_name, name_end - hdr->ar_name);
    }
  else if (hdr->ar_name[1] == ' ')
    {
      // This is the symbol table.
      pname->clear();
    }
  else if (hdr->ar_name[1] == '/')
    {
      // This is the extended name table.
      pname->assign(1, '/');
    }
  else
    {
      errno = 0;
      long x = strtol(hdr->ar_name + 1, &end, 10);
      if (*end != ' '
	  || x < 0
	  || (x == LONG_MAX && errno == ERANGE)
	  || static_cast<size_t>(x) >= this->extended_names_.size())
	{
	  fprintf(stderr, _("%s: %s: bad extended name index at %ld\n"),
		  program_name, this->name().c_str(),
		  static_cast<long>(off));
	  gold_exit(false);
	}

      const char* name = this->extended_names_.data() + x;
      const char* name_end = strchr(name, '/');
      if (static_cast<size_t>(name_end - name) > this->extended_names_.size()
	  || name_end[1] != '\n')
	{
	  fprintf(stderr, _("%s: %s: bad extended name entry at header %ld\n"),
		  program_name, this->name().c_str(),
		  static_cast<long>(off));
	  gold_exit(false);
	}
      pname->assign(name, name_end - name);
    }

  return member_size;
}

// Select members from the archive and add them to the link.  We walk
// through the elements in the archive map, and look each one up in
// the symbol table.  If it exists as a strong undefined symbol, we
// pull in the corresponding element.  We have to do this in a loop,
// since pulling in one element may create new undefined symbols which
// may be satisfied by other objects in the archive.

void
Archive::add_symbols(Symbol_table* symtab, Layout* layout,
		     Input_objects* input_objects)
{
  const size_t armap_size = this->armap_.size();

  bool added_new_object;
  do
    {
      added_new_object = false;
      off_t last = -1;
      for (size_t i = 0; i < armap_size; ++i)
	{
	  if (this->seen_[i])
	    continue;
	  if (this->armap_[i].offset == last)
	    {
	      this->seen_[i] = true;
	      continue;
	    }

	  Symbol* sym = symtab->lookup(this->armap_[i].name);
	  if (sym == NULL)
	    continue;
	  else if (!sym->is_undefined())
	    {
	      this->seen_[i] = true;
	      continue;
	    }
	  else if (sym->binding() == elfcpp::STB_WEAK)
	    continue;

	  // We want to include this object in the link.
	  last = this->armap_[i].offset;
	  this->include_member(symtab, layout, input_objects, last);
	  this->seen_[i] = true;
	  added_new_object = true;
	}
    }
  while (added_new_object);
}

// Include an archive member in the link.  OFF is the file offset of
// the member header.

void
Archive::include_member(Symbol_table* symtab, Layout* layout,
			Input_objects* input_objects, off_t off)
{
  std::string n;
  this->read_header(off, &n);

  size_t memoff = off + sizeof(Archive_header);

  // Read enough of the file to pick up the entire ELF header.
  int ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
  off_t bytes;
  const unsigned char* p = this->input_file_->file().get_view(memoff,
							      ehdr_size,
							      &bytes);
  if (bytes < 4)
    {
      fprintf(stderr, _("%s: %s: member at %ld is not an ELF object"),
	      program_name, this->name().c_str(),
	      static_cast<long>(off));
      gold_exit(false);
    }

  static unsigned char elfmagic[4] =
    {
      elfcpp::ELFMAG0, elfcpp::ELFMAG1,
      elfcpp::ELFMAG2, elfcpp::ELFMAG3
    };
  if (memcmp(p, elfmagic, 4) != 0)
    {
      fprintf(stderr, _("%s: %s: member at %ld is not an ELF object"),
	      program_name, this->name().c_str(),
	      static_cast<long>(off));
      gold_exit(false);
    }

  Object* obj = make_elf_object((std::string(this->input_file_->filename())
				 + "(" + n + ")"),
				this->input_file_, memoff, p, bytes);

  input_objects->add_object(obj);

  Read_symbols_data sd;
  obj->read_symbols(&sd);
  obj->layout(layout, &sd);
  obj->add_symbols(symtab, &sd);
}

// Add_archive_symbols methods.

Add_archive_symbols::~Add_archive_symbols()
{
  if (this->this_blocker_ != NULL)
    delete this->this_blocker_;
  // next_blocker_ is deleted by the task associated with the next
  // input file.
}

// Return whether we can add the archive symbols.  We are blocked by
// this_blocker_.  We block next_blocker_.  We also lock the file.

Task::Is_runnable_type
Add_archive_symbols::is_runnable(Workqueue*)
{
  if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
    return IS_BLOCKED;
  return IS_RUNNABLE;
}

class Add_archive_symbols::Add_archive_symbols_locker : public Task_locker
{
 public:
  Add_archive_symbols_locker(Task_token& token, Workqueue* workqueue,
			     File_read& file)
    : blocker_(token, workqueue), filelock_(file)
  { }

 private:
  Task_locker_block blocker_;
  Task_locker_obj<File_read> filelock_;			     
};

Task_locker*
Add_archive_symbols::locks(Workqueue* workqueue)
{
  return new Add_archive_symbols_locker(*this->next_blocker_,
					workqueue,
					this->archive_->file());
}

void
Add_archive_symbols::run(Workqueue*)
{
  this->archive_->add_symbols(this->symtab_, this->layout_,
			      this->input_objects_);

  if (this->input_group_ != NULL)
    this->input_group_->add_archive(this->archive_);
  else
    {
      // We no longer need to know about this archive.
      delete this->archive_;
    }
}

} // End namespace gold.