gold/dirsearch.cc

   1 // dirsearch.cc -- directory searching for gold
   2
   3 // Copyright (C) 2006-2020 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 <sys/stat.h>
  29 #include <dirent.h>
  30
  31 #include "debug.h"
  32 #include "gold-threads.h"
  33 #include "options.h"
  34 #include "workqueue.h"
  35 #include "dirsearch.h"
  36
  37 namespace
  38 {
  39
  40 // Read all the files in a directory.
  41
  42 class Dir_cache
  43 {
  44  public:
  45   Dir_cache(const char* dirname)
  46     : dirname_(dirname), files_()
  47   { }
  48
  49   // Read the files in the directory.
  50   void read_files();
  51
  52   // Return whether a file (a base name) is present in the directory.
  53   bool find(const std::string&) const;
  54
  55  private:
  56   // We can not copy this class.
  57   Dir_cache(const Dir_cache&);
  58   Dir_cache& operator=(const Dir_cache&);
  59
  60   const char* dirname_;
  61   Unordered_set<std::string> files_;
  62 };
  63
  64 void
  65 Dir_cache::read_files()
  66 {
  67   DIR* d = opendir(this->dirname_);
  68   if (d == NULL)
  69     {
  70       // We ignore directories which do not exist or are actually file
  71       // names.
  72       if (errno != ENOENT && errno != ENOTDIR)
  73         gold::gold_error(_("%s: can not read directory: %s"),
  74                          this->dirname_, strerror(errno));
  75       return;
  76     }
  77
  78   dirent* de;
  79   while ((de = readdir(d)) != NULL)
  80     this->files_.insert(std::string(de->d_name));
  81
  82   if (closedir(d) != 0)
  83     gold::gold_warning("%s: closedir failed: %s", this->dirname_,
  84                        strerror(errno));
  85 }
  86
  87 bool
  88 Dir_cache::find(const std::string& basename) const
  89 {
  90   return this->files_.find(basename) != this->files_.end();
  91 }
  92
  93 // A mapping from directory names to caches.  A lock permits
  94 // concurrent update.  There is no lock for read operations--some
  95 // other mechanism must be used to prevent reads from conflicting with
  96 // writes.
  97
  98 class Dir_caches
  99 {
 100  public:
 101   Dir_caches()
 102     : lock_(), caches_()
 103   { }
 104
 105   ~Dir_caches() ATTRIBUTE_UNUSED;
 106
 107   // Add a cache for a directory.
 108   void add(const char*);
 109
 110   // Look up a directory in the cache.  This much be locked against
 111   // calls to Add.
 112   Dir_cache* lookup(const char*) const;
 113
 114  private:
 115   // We can not copy this class.
 116   Dir_caches(const Dir_caches&);
 117   Dir_caches& operator=(const Dir_caches&);
 118
 119   typedef Unordered_map<const char*, Dir_cache*> Cache_hash;
 120
 121   gold::Lock lock_;
 122   Cache_hash caches_;
 123 };
 124
 125 Dir_caches::~Dir_caches()
 126 {
 127   for (Cache_hash::iterator p = this->caches_.begin();
 128        p != this->caches_.end();
 129        ++p)
 130     delete p->second;
 131 }
 132
 133 void
 134 Dir_caches::add(const char* dirname)
 135 {
 136   {
 137     gold::Hold_lock hl(this->lock_);
 138     if (this->lookup(dirname) != NULL)
 139       return;
 140   }
 141
 142   Dir_cache* cache = new Dir_cache(dirname);
 143
 144   cache->read_files();
 145
 146   {
 147     gold::Hold_lock hl(this->lock_);
 148
 149     std::pair<const char*, Dir_cache*> v(dirname, cache);
 150     std::pair<Cache_hash::iterator, bool> p = this->caches_.insert(v);
 151     gold_assert(p.second);
 152   }
 153 }
 154
 155 Dir_cache*
 156 Dir_caches::lookup(const char* dirname) const
 157 {
 158   Cache_hash::const_iterator p = this->caches_.find(dirname);
 159   if (p == this->caches_.end())
 160     return NULL;
 161   return p->second;
 162 }
 163
 164 // The caches.
 165
 166 Dir_caches* caches;
 167
 168 // A Task to read the directory.
 169
 170 class Dir_cache_task : public gold::Task
 171 {
 172  public:
 173   Dir_cache_task(const char* dir, gold::Task_token& token)
 174     : dir_(dir), token_(token)
 175   { }
 176
 177   gold::Task_token*
 178   is_runnable();
 179
 180   void
 181   locks(gold::Task_locker*);
 182
 183   void
 184   run(gold::Workqueue*);
 185
 186   std::string
 187   get_name() const
 188   { return std::string("Dir_cache_task ") + this->dir_; }
 189
 190  private:
 191   const char* dir_;
 192   gold::Task_token& token_;
 193 };
 194
 195 // We can always run the task to read the directory.
 196
 197 gold::Task_token*
 198 Dir_cache_task::is_runnable()
 199 {
 200   return NULL;
 201 }
 202
 203 // Return the locks to hold.  We use a blocker lock to prevent file
 204 // lookups from starting until the directory contents have been read.
 205
 206 void
 207 Dir_cache_task::locks(gold::Task_locker* tl)
 208 {
 209   tl->add(this, &this->token_);
 210 }
 211
 212 // Run the task--read the directory contents.
 213
 214 void
 215 Dir_cache_task::run(gold::Workqueue*)
 216 {
 217   caches->add(this->dir_);
 218 }
 219
 220 }
 221
 222 namespace gold
 223 {
 224
 225 // Initialize.
 226
 227 void
 228 Dirsearch::initialize(Workqueue* workqueue,
 229                       const General_options::Dir_list* directories)
 230 {
 231   gold_assert(caches == NULL);
 232   caches = new Dir_caches;
 233   this->directories_ = directories;
 234   this->token_.add_blockers(directories->size());
 235   for (General_options::Dir_list::const_iterator p = directories->begin();
 236        p != directories->end();
 237        ++p)
 238     workqueue->queue(new Dir_cache_task(p->name().c_str(), this->token_));
 239 }
 240
 241 // Search for a file.  NOTE: we only log failed file-lookup attempts
 242 // here.  Successfully lookups will eventually get logged in
 243 // File_read::open.
 244
 245 std::string
 246 Dirsearch::find(const std::vector<std::string>& names,
 247                 bool* is_in_sysroot, int* pindex,
 248                 std::string *found_name) const
 249 {
 250   gold_assert(!this->token_.is_blocked());
 251   gold_assert(*pindex >= 0);
 252
 253   for (unsigned int i = static_cast<unsigned int>(*pindex);
 254        i < this->directories_->size();
 255        ++i)
 256     {
 257       const Search_directory* p = &this->directories_->at(i);
 258       Dir_cache* pdc = caches->lookup(p->name().c_str());
 259       gold_assert(pdc != NULL);
 260       for (std::vector<std::string>::const_iterator n = names.begin();
 261            n != names.end();
 262            ++n)
 263         {
 264           if (pdc->find(*n))
 265             {
 266               *is_in_sysroot = p->is_in_sysroot();
 267               *pindex = i;
 268               *found_name = *n;
 269               return p->name() + '/' + *n;
 270             }
 271           else
 272             gold_debug(DEBUG_FILES, "Attempt to open %s/%s failed",
 273                        p->name().c_str(), (*n).c_str());
 274         }
 275     }
 276
 277   *pindex = -2;
 278   return std::string();
 279 }
 280
 281 // Search for a file in a directory list.  This is a low-level function and
 282 // therefore can be used before options and parameters are set.
 283
 284 std::string
 285 Dirsearch::find_file_in_dir_list(const std::string& name,
 286                                  const General_options::Dir_list& directories,
 287                                  const std::string& extra_search_dir)
 288 {
 289   struct stat buf;
 290   std::string extra_name = extra_search_dir + '/' + name;
 291
 292   if (stat(extra_name.c_str(), &buf) == 0)
 293     return extra_name;
 294   for (General_options::Dir_list::const_iterator dir = directories.begin();
 295        dir != directories.end();
 296        ++dir)
 297     {
 298       std::string full_name = dir->name() + '/' + name;
 299       if (stat(full_name.c_str(), &buf) == 0)
 300         return full_name;
 301     }
 302   return name;
 303 }
 304
 305 } // End namespace gold.