gold/dirsearch.cc

   1 // dirsearch.cc -- directory searching for gold
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 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 <sys/types.h>
  28 #include <dirent.h>
  29
  30 #include "debug.h"
  31 #include "gold-threads.h"
  32 #include "options.h"
  33 #include "workqueue.h"
  34 #include "dirsearch.h"
  35
  36 namespace
  37 {
  38
  39 // Read all the files in a directory.
  40
  41 class Dir_cache
  42 {
  43  public:
  44   Dir_cache(const char* dirname)
  45     : dirname_(dirname), files_()
  46   { }
  47
  48   // Read the files in the directory.
  49   void read_files();
  50
  51   // Return whether a file (a base name) is present in the directory.
  52   bool find(const std::string&) const;
  53
  54  private:
  55   // We can not copy this class.
  56   Dir_cache(const Dir_cache&);
  57   Dir_cache& operator=(const Dir_cache&);
  58
  59   const char* dirname_;
  60   Unordered_set<std::string> files_;
  61 };
  62
  63 void
  64 Dir_cache::read_files()
  65 {
  66   DIR* d = opendir(this->dirname_);
  67   if (d == NULL)
  68     {
  69       // We ignore directories which do not exist or are actually file
  70       // names.
  71       if (errno != ENOENT && errno != ENOTDIR)
  72         gold::gold_error(_("%s: can not read directory: %s"),
  73                          this->dirname_, strerror(errno));
  74       return;
  75     }
  76
  77   dirent* de;
  78   while ((de = readdir(d)) != NULL)
  79     this->files_.insert(std::string(de->d_name));
  80
  81   if (closedir(d) != 0)
  82     gold::gold_warning("%s: closedir failed: %s", this->dirname_,
  83                        strerror(errno));
  84 }
  85
  86 bool
  87 Dir_cache::find(const std::string& basename) const
  88 {
  89   return this->files_.find(basename) != this->files_.end();
  90 }
  91
  92 // A mapping from directory names to caches.  A lock permits
  93 // concurrent update.  There is no lock for read operations--some
  94 // other mechanism must be used to prevent reads from conflicting with
  95 // writes.
  96
  97 class Dir_caches
  98 {
  99  public:
 100   Dir_caches()
 101     : lock_(), caches_()
 102   { }
 103
 104   ~Dir_caches();
 105
 106   // Add a cache for a directory.
 107   void add(const char*);
 108
 109   // Look up a directory in the cache.  This much be locked against
 110   // calls to Add.
 111   Dir_cache* lookup(const char*) const;
 112
 113  private:
 114   // We can not copy this class.
 115   Dir_caches(const Dir_caches&);
 116   Dir_caches& operator=(const Dir_caches&);
 117
 118   typedef Unordered_map<const char*, Dir_cache*> Cache_hash;
 119
 120   gold::Lock lock_;
 121   Cache_hash caches_;
 122 };
 123
 124 Dir_caches::~Dir_caches()
 125 {
 126   for (Cache_hash::iterator p = this->caches_.begin();
 127        p != this->caches_.end();
 128        ++p)
 129     delete p->second;
 130 }
 131
 132 void
 133 Dir_caches::add(const char* dirname)
 134 {
 135   {
 136     gold::Hold_lock hl(this->lock_);
 137     if (this->lookup(dirname) != NULL)
 138       return;
 139   }
 140
 141   Dir_cache* cache = new Dir_cache(dirname);
 142
 143   cache->read_files();
 144
 145   {
 146     gold::Hold_lock hl(this->lock_);
 147
 148     std::pair<const char*, Dir_cache*> v(dirname, cache);
 149     std::pair<Cache_hash::iterator, bool> p = this->caches_.insert(v);
 150     gold_assert(p.second);
 151   }
 152 }
 153
 154 Dir_cache*
 155 Dir_caches::lookup(const char* dirname) const
 156 {
 157   Cache_hash::const_iterator p = this->caches_.find(dirname);
 158   if (p == this->caches_.end())
 159     return NULL;
 160   return p->second;
 161 }
 162
 163 // The caches.
 164
 165 Dir_caches* caches;
 166
 167 // A Task to read the directory.
 168
 169 class Dir_cache_task : public gold::Task
 170 {
 171  public:
 172   Dir_cache_task(const char* dir, gold::Task_token& token)
 173     : dir_(dir), token_(token)
 174   { }
 175
 176   gold::Task_token*
 177   is_runnable();
 178
 179   void
 180   locks(gold::Task_locker*);
 181
 182   void
 183   run(gold::Workqueue*);
 184
 185   std::string
 186   get_name() const
 187   { return std::string("Dir_cache_task ") + this->dir_; }
 188
 189  private:
 190   const char* dir_;
 191   gold::Task_token& token_;
 192 };
 193
 194 // We can always run the task to read the directory.
 195
 196 gold::Task_token*
 197 Dir_cache_task::is_runnable()
 198 {
 199   return NULL;
 200 }
 201
 202 // Return the locks to hold.  We use a blocker lock to prevent file
 203 // lookups from starting until the directory contents have been read.
 204
 205 void
 206 Dir_cache_task::locks(gold::Task_locker* tl)
 207 {
 208   tl->add(this, &this->token_);
 209 }
 210
 211 // Run the task--read the directory contents.
 212
 213 void
 214 Dir_cache_task::run(gold::Workqueue*)
 215 {
 216   caches->add(this->dir_);
 217 }
 218
 219 }
 220
 221 namespace gold
 222 {
 223
 224 // Initialize.
 225
 226 void
 227 Dirsearch::initialize(Workqueue* workqueue,
 228                       const General_options::Dir_list* directories)
 229 {
 230   gold_assert(caches == NULL);
 231   caches = new Dir_caches;
 232   this->directories_ = directories;
 233   this->token_.add_blockers(directories->size());
 234   for (General_options::Dir_list::const_iterator p = directories->begin();
 235        p != directories->end();
 236        ++p)
 237     workqueue->queue(new Dir_cache_task(p->name().c_str(), this->token_));
 238 }
 239
 240 // Search for a file.  NOTE: we only log failed file-lookup attempts
 241 // here.  Successfully lookups will eventually get logged in
 242 // File_read::open.
 243
 244 std::string
 245 Dirsearch::find(const std::vector<std::string>& names,
 246                 bool* is_in_sysroot, int* pindex,
 247                 std::string *found_name) const
 248 {
 249   gold_assert(!this->token_.is_blocked());
 250   gold_assert(*pindex >= 0);
 251
 252   for (unsigned int i = static_cast<unsigned int>(*pindex);
 253        i < this->directories_->size();
 254        ++i)
 255     {
 256       const Search_directory* p = &this->directories_->at(i);
 257       Dir_cache* pdc = caches->lookup(p->name().c_str());
 258       gold_assert(pdc != NULL);
 259       for (std::vector<std::string>::const_iterator n = names.begin();
 260            n != names.end();
 261            ++n)
 262         {
 263           if (pdc->find(*n))
 264             {
 265               *is_in_sysroot = p->is_in_sysroot();
 266               *pindex = i;
 267               *found_name = *n;
 268               return p->name() + '/' + *n;
 269             }
 270           else
 271             gold_debug(DEBUG_FILES, "Attempt to open %s/%s failed",
 272                        p->name().c_str(), (*n).c_str());
 273         }
 274     }
 275
 276   *pindex = -2;
 277   return std::string();
 278 }
 279
 280 } // End namespace gold.