gold/fileread.cc

   1 // fileread.cc -- read files for gold
   2
   3 #include "gold.h"
   4
   5 #include <cstring>
   6 #include <cerrno>
   7 #include <fcntl.h>
   8 #include <unistd.h>
   9
  10 #include "options.h"
  11 #include "dirsearch.h"
  12 #include "fileread.h"
  13
  14 namespace gold
  15 {
  16
  17 // Class File_read::View.
  18
  19 File_read::View::~View()
  20 {
  21   gold_assert(!this->is_locked());
  22   delete[] this->data_;
  23 }
  24
  25 void
  26 File_read::View::lock()
  27 {
  28   ++this->lock_count_;
  29 }
  30
  31 void
  32 File_read::View::unlock()
  33 {
  34   gold_assert(this->lock_count_ > 0);
  35   --this->lock_count_;
  36 }
  37
  38 bool
  39 File_read::View::is_locked()
  40 {
  41   return this->lock_count_ > 0;
  42 }
  43
  44 // Class File_read.
  45
  46 // The File_read class is designed to support file descriptor caching,
  47 // but this is not currently implemented.
  48
  49 File_read::~File_read()
  50 {
  51   gold_assert(this->lock_count_ == 0);
  52   if (this->descriptor_ >= 0)
  53     {
  54       if (close(this->descriptor_) < 0)
  55         fprintf(stderr, _("%s: warning: close(%s) failed: %s"),
  56                 program_name, this->name_.c_str(), strerror(errno));
  57       this->descriptor_ = -1;
  58     }
  59   this->name_.clear();
  60   this->clear_views(true);
  61 }
  62
  63 // Open the file.
  64
  65 bool
  66 File_read::open(const std::string& name)
  67 {
  68   gold_assert(this->lock_count_ == 0
  69               && this->descriptor_ < 0
  70               && this->name_.empty());
  71   this->name_ = name;
  72   this->descriptor_ = ::open(this->name_.c_str(), O_RDONLY);
  73   ++this->lock_count_;
  74   return this->descriptor_ >= 0;
  75 }
  76
  77 // Open the file for testing purposes.
  78
  79 bool
  80 File_read::open(const std::string& name, const unsigned char* contents,
  81                 off_t contents_size)
  82 {
  83   gold_assert(this->lock_count_ == 0
  84               && this->descriptor_ < 0
  85               && this->name_.empty());
  86   this->name_ = name;
  87   this->contents_ = contents;
  88   this->contents_size_ = contents_size;
  89   ++this->lock_count_;
  90   return true;
  91 }
  92
  93 void
  94 File_read::lock()
  95 {
  96   ++this->lock_count_;
  97 }
  98
  99 void
 100 File_read::unlock()
 101 {
 102   gold_assert(this->lock_count_ > 0);
 103   --this->lock_count_;
 104 }
 105
 106 bool
 107 File_read::is_locked()
 108 {
 109   return this->lock_count_ > 0;
 110 }
 111
 112 // See if we have a view which covers the file starting at START for
 113 // SIZE bytes.  Return a pointer to the View if found, NULL if not.
 114
 115 inline File_read::View*
 116 File_read::find_view(off_t start, off_t size)
 117 {
 118   off_t page = File_read::page_offset(start);
 119   Views::iterator p = this->views_.find(page);
 120   if (p == this->views_.end())
 121     return NULL;
 122   if (p->second->size() - (start - page) < size)
 123     return NULL;
 124   return p->second;
 125 }
 126
 127 // Read data from the file.  Return the number of bytes read.  If
 128 // PBYTES is not NULL, store the number of bytes in *PBYTES, otherwise
 129 // require that we read exactly the number of bytes requested.
 130
 131 off_t
 132 File_read::do_read(off_t start, off_t size, void* p, off_t* pbytes)
 133 {
 134   gold_assert(this->lock_count_ > 0);
 135
 136   off_t bytes;
 137   if (this->contents_ == NULL)
 138     {
 139       int o = this->descriptor_;
 140
 141       if (lseek(o, start, SEEK_SET) < 0)
 142         {
 143           fprintf(stderr, _("%s: %s: lseek to %lld failed: %s"),
 144                   program_name, this->filename().c_str(),
 145                   static_cast<long long>(start),
 146                   strerror(errno));
 147           gold_exit(false);
 148         }
 149
 150       bytes = ::read(o, p, size);
 151       if (bytes < 0)
 152         {
 153           fprintf(stderr, _("%s: %s: read failed: %s\n"),
 154                   program_name, this->filename().c_str(), strerror(errno));
 155           gold_exit(false);
 156         }
 157     }
 158   else
 159     {
 160       bytes = this->contents_size_ - start;
 161       if (bytes < 0)
 162         bytes = 0;
 163       else if (bytes > size)
 164         bytes = size;
 165       memcpy(p, this->contents_ + start, bytes);
 166     }
 167
 168   if (pbytes != NULL)
 169     *pbytes = bytes;
 170   else if (bytes != size)
 171     {
 172       fprintf(stderr,
 173               _("%s: %s: file too short: read only %lld of %lld "
 174                 "bytes at %lld\n"),
 175               program_name, this->filename().c_str(),
 176               static_cast<long long>(bytes),
 177               static_cast<long long>(size),
 178               static_cast<long long>(start));
 179       gold_exit(false);
 180     }
 181
 182   return bytes;
 183 }
 184
 185 void
 186 File_read::read(off_t start, off_t size, void* p, off_t* pbytes)
 187 {
 188   gold_assert(this->lock_count_ > 0);
 189
 190   File_read::View* pv = this->find_view(start, size);
 191   if (pv != NULL)
 192     {
 193       memcpy(p, pv->data() + (start - pv->start()), size);
 194       if (pbytes != NULL)
 195         *pbytes = size;
 196       return;
 197     }
 198
 199   this->do_read(start, size, p, pbytes);
 200 }
 201
 202 // Find an existing view or make a new one.
 203
 204 File_read::View*
 205 File_read::find_or_make_view(off_t start, off_t size, off_t* pbytes)
 206 {
 207   gold_assert(this->lock_count_ > 0);
 208
 209   off_t poff = File_read::page_offset(start);
 210
 211   File_read::View* const vnull = NULL;
 212   std::pair<Views::iterator, bool> ins =
 213     this->views_.insert(std::make_pair(poff, vnull));
 214
 215   if (!ins.second)
 216     {
 217       // There was an existing view at this offset.
 218       File_read::View* v = ins.first->second;
 219       if (v->size() - (start - v->start()) >= size)
 220         {
 221           if (pbytes != NULL)
 222             *pbytes = size;
 223           return v;
 224         }
 225
 226       // This view is not large enough.
 227       this->saved_views_.push_back(v);
 228     }
 229
 230   // We need to read data from the file.
 231
 232   off_t psize = File_read::pages(size + (start - poff));
 233   unsigned char* p = new unsigned char[psize];
 234
 235   off_t got_bytes;
 236   off_t bytes = this->do_read(poff, psize, p, &got_bytes);
 237
 238   File_read::View* v = new File_read::View(poff, bytes, p);
 239
 240   ins.first->second = v;
 241
 242   if (bytes - (start - poff) >= size)
 243     {
 244       if (pbytes != NULL)
 245         *pbytes = size;
 246       return v;
 247     }
 248
 249   if (pbytes != NULL)
 250     {
 251       *pbytes = bytes - (start - poff);
 252       return v;
 253     }
 254
 255   fprintf(stderr,
 256           _("%s: %s: file too short: read only %lld of %lld bytes at %lld\n"),
 257           program_name, this->filename().c_str(),
 258           static_cast<long long>(bytes - (start - poff)),
 259           static_cast<long long>(size),
 260           static_cast<long long>(start));
 261   gold_exit(false);
 262 }
 263
 264 // This implementation of get_view just reads into a memory buffer,
 265 // which we store on view_list_.  At some point we should support
 266 // mmap.
 267
 268 const unsigned char*
 269 File_read::get_view(off_t start, off_t size, off_t* pbytes)
 270 {
 271   gold_assert(this->lock_count_ > 0);
 272   File_read::View* pv = this->find_or_make_view(start, size, pbytes);
 273   return pv->data() + (start - pv->start());
 274 }
 275
 276 File_view*
 277 File_read::get_lasting_view(off_t start, off_t size, off_t* pbytes)
 278 {
 279   gold_assert(this->lock_count_ > 0);
 280   File_read::View* pv = this->find_or_make_view(start, size, pbytes);
 281   pv->lock();
 282   return new File_view(*this, pv, pv->data() + (start - pv->start()));
 283 }
 284
 285 // Remove all the file views.
 286
 287 void
 288 File_read::clear_views(bool destroying)
 289 {
 290   for (Views::iterator p = this->views_.begin();
 291        p != this->views_.end();
 292        ++p)
 293     {
 294       if (!p->second->is_locked())
 295         delete p->second;
 296       else
 297         {
 298           gold_assert(!destroying);
 299           this->saved_views_.push_back(p->second);
 300         }
 301     }
 302   this->views_.clear();
 303
 304   Saved_views::iterator p = this->saved_views_.begin();
 305   while (p != this->saved_views_.end())
 306     {
 307       if (!(*p)->is_locked())
 308         {
 309           delete *p;
 310           p = this->saved_views_.erase(p);
 311         }
 312       else
 313         {
 314           gold_assert(!destroying);
 315           ++p;
 316         }
 317     }
 318 }
 319
 320 // Class File_view.
 321
 322 File_view::~File_view()
 323 {
 324   gold_assert(this->file_.is_locked());
 325   this->view_->unlock();
 326 }
 327
 328 // Class Input_file.
 329
 330 // Create a file for testing.
 331
 332 Input_file::Input_file(const char* name, const unsigned char* contents,
 333                        off_t size)
 334   : file_()
 335 {
 336   this->input_argument_ =
 337     new Input_file_argument(name, false, Position_dependent_options());
 338   bool ok = file_.open(name, contents, size);
 339   gold_assert(ok);
 340 }
 341
 342 // Open the file.
 343
 344 void
 345 Input_file::open(const General_options& options, const Dirsearch& dirpath)
 346 {
 347   std::string name;
 348   if (!this->input_argument_->is_lib())
 349     name = this->input_argument_->name();
 350   else
 351     {
 352       std::string n1("lib");
 353       n1 += this->input_argument_->name();
 354       std::string n2;
 355       if (options.is_static())
 356         n1 += ".a";
 357       else
 358         {
 359           n2 = n1 + ".a";
 360           n1 += ".so";
 361         }
 362       name = dirpath.find(n1, n2);
 363       if (name.empty())
 364         {
 365           fprintf(stderr, _("%s: cannot find %s\n"), program_name,
 366                   this->input_argument_->name());
 367           gold_exit(false);
 368         }
 369     }
 370
 371   if (!this->file_.open(name))
 372     {
 373       fprintf(stderr, _("%s: cannot open %s: %s\n"), program_name,
 374               name.c_str(), strerror(errno));
 375       gold_exit(false);
 376     }
 377 }
 378
 379 } // End namespace gold.