1 // fileread.cc -- read files 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 <cstring>
26 #include <cerrno>
27 #include <climits>
28 #include <fcntl.h>
29 #include <unistd.h>
30 
31 #ifdef HAVE_SYS_MMAN_H
32 #include <sys/mman.h>
33 #endif
34 
35 #ifdef HAVE_READV
36 #include <sys/uio.h>
37 #endif
38 
39 #include <sys/stat.h>
40 #include "filenames.h"
41 
42 #include "debug.h"
43 #include "parameters.h"
44 #include "options.h"
45 #include "dirsearch.h"
46 #include "target.h"
47 #include "binary.h"
48 #include "descriptors.h"
49 #include "gold-threads.h"
50 #include "fileread.h"
51 
52 // For systems without mmap support.
53 #ifndef HAVE_MMAP
54 # define mmap gold_mmap
55 # define munmap gold_munmap
56 # ifndef MAP_FAILED
57 #  define MAP_FAILED (reinterpret_cast<void*>(-1))
58 # endif
59 # ifndef PROT_READ
60 #  define PROT_READ 0
61 # endif
62 # ifndef MAP_PRIVATE
63 #  define MAP_PRIVATE 0
64 # endif
65 
66 # ifndef ENOSYS
67 #  define ENOSYS EINVAL
68 # endif
69 
70 static void *
gold_mmap(void *,size_t,int,int,int,off_t)71 gold_mmap(void *, size_t, int, int, int, off_t)
72 {
73   errno = ENOSYS;
74   return MAP_FAILED;
75 }
76 
77 static int
gold_munmap(void *,size_t)78 gold_munmap(void *, size_t)
79 {
80   errno = ENOSYS;
81   return -1;
82 }
83 
84 #endif
85 
86 #ifndef HAVE_READV
87 struct iovec { void* iov_base; size_t iov_len; };
88 ssize_t
readv(int,const iovec *,int)89 readv(int, const iovec*, int)
90 {
91   gold_unreachable();
92 }
93 #endif
94 
95 namespace gold
96 {
97 
98 // Get the last modified time of an unopened file.
99 
100 bool
get_mtime(const char * filename,Timespec * mtime)101 get_mtime(const char* filename, Timespec* mtime)
102 {
103   struct stat file_stat;
104 
105   if (stat(filename, &file_stat) < 0)
106     return false;
107 #ifdef HAVE_STAT_ST_MTIM
108   mtime->seconds = file_stat.st_mtim.tv_sec;
109   mtime->nanoseconds = file_stat.st_mtim.tv_nsec;
110 #else
111   mtime->seconds = file_stat.st_mtime;
112   mtime->nanoseconds = 0;
113 #endif
114   return true;
115 }
116 
117 // Class File_read.
118 
119 // A lock for the File_read static variables.
120 static Lock* file_counts_lock = NULL;
121 static Initialize_lock file_counts_initialize_lock(&file_counts_lock);
122 
123 // The File_read static variables.
124 unsigned long long File_read::total_mapped_bytes;
125 unsigned long long File_read::current_mapped_bytes;
126 unsigned long long File_read::maximum_mapped_bytes;
127 
128 // Class File_read::View.
129 
~View()130 File_read::View::~View()
131 {
132   gold_assert(!this->is_locked());
133   switch (this->data_ownership_)
134     {
135     case DATA_ALLOCATED_ARRAY:
136       free(const_cast<unsigned char*>(this->data_));
137       break;
138     case DATA_MMAPPED:
139       if (::munmap(const_cast<unsigned char*>(this->data_), this->size_) != 0)
140 	gold_warning(_("munmap failed: %s"), strerror(errno));
141       if (!parameters->options_valid() || parameters->options().stats())
142 	{
143 	  file_counts_initialize_lock.initialize();
144 	  Hold_optional_lock hl(file_counts_lock);
145 	  File_read::current_mapped_bytes -= this->size_;
146 	}
147       break;
148     case DATA_NOT_OWNED:
149       break;
150     default:
151       gold_unreachable();
152     }
153 }
154 
155 void
lock()156 File_read::View::lock()
157 {
158   ++this->lock_count_;
159 }
160 
161 void
unlock()162 File_read::View::unlock()
163 {
164   gold_assert(this->lock_count_ > 0);
165   --this->lock_count_;
166 }
167 
168 bool
is_locked()169 File_read::View::is_locked()
170 {
171   return this->lock_count_ > 0;
172 }
173 
174 // Class File_read.
175 
~File_read()176 File_read::~File_read()
177 {
178   gold_assert(this->token_.is_writable());
179   if (this->is_descriptor_opened_)
180     {
181       release_descriptor(this->descriptor_, true);
182       this->descriptor_ = -1;
183       this->is_descriptor_opened_ = false;
184     }
185   this->name_.clear();
186   this->clear_views(CLEAR_VIEWS_ALL);
187 }
188 
189 // Open the file.
190 
191 bool
open(const Task * task,const std::string & name)192 File_read::open(const Task* task, const std::string& name)
193 {
194   gold_assert(this->token_.is_writable()
195 	      && this->descriptor_ < 0
196 	      && !this->is_descriptor_opened_
197 	      && this->name_.empty());
198   this->name_ = name;
199 
200   this->descriptor_ = open_descriptor(-1, this->name_.c_str(),
201 				      O_RDONLY);
202 
203   if (this->descriptor_ >= 0)
204     {
205       this->is_descriptor_opened_ = true;
206       struct stat s;
207       if (::fstat(this->descriptor_, &s) < 0)
208 	gold_error(_("%s: fstat failed: %s"),
209 		   this->name_.c_str(), strerror(errno));
210       this->size_ = s.st_size;
211       gold_debug(DEBUG_FILES, "Attempt to open %s succeeded",
212 		 this->name_.c_str());
213       this->token_.add_writer(task);
214     }
215 
216   return this->descriptor_ >= 0;
217 }
218 
219 // Open the file with the contents in memory.
220 
221 bool
open(const Task * task,const std::string & name,const unsigned char * contents,off_t size)222 File_read::open(const Task* task, const std::string& name,
223 		const unsigned char* contents, off_t size)
224 {
225   gold_assert(this->token_.is_writable()
226 	      && this->descriptor_ < 0
227 	      && !this->is_descriptor_opened_
228 	      && this->name_.empty());
229   this->name_ = name;
230   this->whole_file_view_ = new View(0, size, contents, 0, false,
231 				    View::DATA_NOT_OWNED);
232   this->add_view(this->whole_file_view_);
233   this->size_ = size;
234   this->token_.add_writer(task);
235   return true;
236 }
237 
238 // Reopen a descriptor if necessary.
239 
240 void
reopen_descriptor()241 File_read::reopen_descriptor()
242 {
243   if (!this->is_descriptor_opened_)
244     {
245       this->descriptor_ = open_descriptor(this->descriptor_,
246 					  this->name_.c_str(),
247 					  O_RDONLY);
248       if (this->descriptor_ < 0)
249 	gold_fatal(_("could not reopen file %s"), this->name_.c_str());
250       this->is_descriptor_opened_ = true;
251     }
252 }
253 
254 // Release the file.  This is called when we are done with the file in
255 // a Task.
256 
257 void
release()258 File_read::release()
259 {
260   gold_assert(this->is_locked());
261 
262   if (!parameters->options_valid() || parameters->options().stats())
263     {
264       file_counts_initialize_lock.initialize();
265       Hold_optional_lock hl(file_counts_lock);
266       File_read::total_mapped_bytes += this->mapped_bytes_;
267       File_read::current_mapped_bytes += this->mapped_bytes_;
268       if (File_read::current_mapped_bytes > File_read::maximum_mapped_bytes)
269 	File_read::maximum_mapped_bytes = File_read::current_mapped_bytes;
270     }
271 
272   this->mapped_bytes_ = 0;
273 
274   // Only clear views if there is only one attached object.  Otherwise
275   // we waste time trying to clear cached archive views.  Similarly
276   // for releasing the descriptor.
277   if (this->object_count_ <= 1)
278     {
279       this->clear_views(CLEAR_VIEWS_NORMAL);
280       if (this->is_descriptor_opened_)
281 	{
282 	  release_descriptor(this->descriptor_, false);
283 	  this->is_descriptor_opened_ = false;
284 	}
285     }
286 
287   this->released_ = true;
288 }
289 
290 // Lock the file.
291 
292 void
lock(const Task * task)293 File_read::lock(const Task* task)
294 {
295   gold_assert(this->released_);
296   gold_debug(DEBUG_FILES, "Locking file \"%s\"", this->name_.c_str());
297   this->token_.add_writer(task);
298   this->released_ = false;
299 }
300 
301 // Unlock the file.
302 
303 void
unlock(const Task * task)304 File_read::unlock(const Task* task)
305 {
306   gold_debug(DEBUG_FILES, "Unlocking file \"%s\"", this->name_.c_str());
307   this->release();
308   this->token_.remove_writer(task);
309 }
310 
311 // Return whether the file is locked.
312 
313 bool
is_locked() const314 File_read::is_locked() const
315 {
316   if (!this->token_.is_writable())
317     return true;
318   // The file is not locked, so it should have been released.
319   gold_assert(this->released_);
320   return false;
321 }
322 
323 // See if we have a view which covers the file starting at START for
324 // SIZE bytes.  Return a pointer to the View if found, NULL if not.
325 // If BYTESHIFT is not -1U, the returned View must have the specified
326 // byte shift; otherwise, it may have any byte shift.  If VSHIFTED is
327 // not NULL, this sets *VSHIFTED to a view which would have worked if
328 // not for the requested BYTESHIFT.
329 
330 inline File_read::View*
find_view(off_t start,section_size_type size,unsigned int byteshift,File_read::View ** vshifted) const331 File_read::find_view(off_t start, section_size_type size,
332 		     unsigned int byteshift, File_read::View** vshifted) const
333 {
334   gold_assert(start <= this->size_
335 	      && (static_cast<unsigned long long>(size)
336 		  <= static_cast<unsigned long long>(this->size_ - start)));
337 
338   if (vshifted != NULL)
339     *vshifted = NULL;
340 
341   // If we have the whole file mmapped, and the alignment is right,
342   // we can return it.
343   if (this->whole_file_view_)
344     if (byteshift == -1U || byteshift == 0)
345       return this->whole_file_view_;
346 
347   off_t page = File_read::page_offset(start);
348 
349   unsigned int bszero = 0;
350   Views::const_iterator p = this->views_.upper_bound(std::make_pair(page - 1,
351 								    bszero));
352 
353   while (p != this->views_.end() && p->first.first <= page)
354     {
355       if (p->second->start() <= start
356 	  && (p->second->start() + static_cast<off_t>(p->second->size())
357 	      >= start + static_cast<off_t>(size)))
358 	{
359 	  if (byteshift == -1U || byteshift == p->second->byteshift())
360 	    {
361 	      p->second->set_accessed();
362 	      return p->second;
363 	    }
364 
365 	  if (vshifted != NULL && *vshifted == NULL)
366 	    *vshifted = p->second;
367 	}
368 
369       ++p;
370     }
371 
372   return NULL;
373 }
374 
375 // Read SIZE bytes from the file starting at offset START.  Read into
376 // the buffer at P.
377 
378 void
do_read(off_t start,section_size_type size,void * p)379 File_read::do_read(off_t start, section_size_type size, void* p)
380 {
381   ssize_t bytes;
382   if (this->whole_file_view_ != NULL)
383     {
384       bytes = this->size_ - start;
385       if (static_cast<section_size_type>(bytes) >= size)
386 	{
387 	  memcpy(p, this->whole_file_view_->data() + start, size);
388 	  return;
389 	}
390     }
391   else
392     {
393       this->reopen_descriptor();
394 
395       char *read_ptr = static_cast<char *>(p);
396       off_t read_pos = start;
397       size_t to_read = size;
398       do
399 	{
400 	  bytes = ::pread(this->descriptor_, read_ptr, to_read, read_pos);
401 	  if (bytes < 0)
402 	    gold_fatal(_("%s: pread failed: %s"),
403 		       this->filename().c_str(), strerror(errno));
404 
405 	  read_pos += bytes;
406 	  read_ptr += bytes;
407 	  to_read -= bytes;
408 	  if (to_read == 0)
409 	    return;
410 	}
411       while (bytes > 0);
412 
413       bytes = size - to_read;
414     }
415 
416   gold_fatal(_("%s: file too short: read only %lld of %lld bytes at %lld"),
417 	     this->filename().c_str(),
418 	     static_cast<long long>(bytes),
419 	     static_cast<long long>(size),
420 	     static_cast<long long>(start));
421 }
422 
423 // Read data from the file.
424 
425 void
read(off_t start,section_size_type size,void * p)426 File_read::read(off_t start, section_size_type size, void* p)
427 {
428   const File_read::View* pv = this->find_view(start, size, -1U, NULL);
429   if (pv != NULL)
430     {
431       memcpy(p, pv->data() + (start - pv->start() + pv->byteshift()), size);
432       return;
433     }
434 
435   this->do_read(start, size, p);
436 }
437 
438 // Add a new view.  There may already be an existing view at this
439 // offset.  If there is, the new view will be larger, and should
440 // replace the old view.
441 
442 void
add_view(File_read::View * v)443 File_read::add_view(File_read::View* v)
444 {
445   std::pair<Views::iterator, bool> ins =
446     this->views_.insert(std::make_pair(std::make_pair(v->start(),
447 						      v->byteshift()),
448 				       v));
449   if (ins.second)
450     return;
451 
452   // There was an existing view at this offset.  It must not be large
453   // enough.  We can't delete it here, since something might be using
454   // it; we put it on a list to be deleted when the file is unlocked.
455   File_read::View* vold = ins.first->second;
456   gold_assert(vold->size() < v->size());
457   if (vold->should_cache())
458     {
459       v->set_cache();
460       vold->clear_cache();
461     }
462   this->saved_views_.push_back(vold);
463 
464   ins.first->second = v;
465 }
466 
467 // Make a new view with a specified byteshift, reading the data from
468 // the file.
469 
470 File_read::View*
make_view(off_t start,section_size_type size,unsigned int byteshift,bool cache)471 File_read::make_view(off_t start, section_size_type size,
472 		     unsigned int byteshift, bool cache)
473 {
474   gold_assert(size > 0);
475   gold_assert(start <= this->size_
476 	      && (static_cast<unsigned long long>(size)
477 		  <= static_cast<unsigned long long>(this->size_ - start)));
478 
479   off_t poff = File_read::page_offset(start);
480 
481   section_size_type psize = File_read::pages(size + (start - poff));
482 
483   if (poff + static_cast<off_t>(psize) >= this->size_)
484     {
485       psize = this->size_ - poff;
486       gold_assert(psize >= size);
487     }
488 
489   void* p;
490   View::Data_ownership ownership;
491   if (byteshift != 0)
492     {
493       p = malloc(psize + byteshift);
494       if (p == NULL)
495 	gold_nomem();
496       memset(p, 0, byteshift);
497       this->do_read(poff, psize, static_cast<unsigned char*>(p) + byteshift);
498       ownership = View::DATA_ALLOCATED_ARRAY;
499     }
500   else
501     {
502       this->reopen_descriptor();
503       p = ::mmap(NULL, psize, PROT_READ, MAP_PRIVATE, this->descriptor_, poff);
504       if (p != MAP_FAILED)
505 	{
506 	  ownership = View::DATA_MMAPPED;
507 	  this->mapped_bytes_ += psize;
508 	}
509       else
510 	{
511 	  p = malloc(psize);
512 	  if (p == NULL)
513 	    gold_nomem();
514 	  this->do_read(poff, psize, p);
515 	  ownership = View::DATA_ALLOCATED_ARRAY;
516 	}
517     }
518 
519   const unsigned char* pbytes = static_cast<const unsigned char*>(p);
520   File_read::View* v = new File_read::View(poff, psize, pbytes, byteshift,
521 					   cache, ownership);
522 
523   this->add_view(v);
524 
525   return v;
526 }
527 
528 // Find a View or make a new one, shifted as required by the file
529 // offset OFFSET and ALIGNED.
530 
531 File_read::View*
find_or_make_view(off_t offset,off_t start,section_size_type size,bool aligned,bool cache)532 File_read::find_or_make_view(off_t offset, off_t start,
533 			     section_size_type size, bool aligned, bool cache)
534 {
535   // Check that start and end of the view are within the file.
536   if (start > this->size_
537       || (static_cast<unsigned long long>(size)
538 	  > static_cast<unsigned long long>(this->size_ - start)))
539     gold_fatal(_("%s: attempt to map %lld bytes at offset %lld exceeds "
540 		 "size of file; the file may be corrupt"),
541 		   this->filename().c_str(),
542 		   static_cast<long long>(size),
543 		   static_cast<long long>(start));
544 
545   unsigned int byteshift;
546   if (offset == 0)
547     byteshift = 0;
548   else
549     {
550       unsigned int target_size = (!parameters->target_valid()
551 				  ? 64
552 				  : parameters->target().get_size());
553       byteshift = offset & ((target_size / 8) - 1);
554 
555       // Set BYTESHIFT to the number of dummy bytes which must be
556       // inserted before the data in order for this data to be
557       // aligned.
558       if (byteshift != 0)
559 	byteshift = (target_size / 8) - byteshift;
560     }
561 
562   // If --map-whole-files is set, make sure we have a
563   // whole file view.  Options may not yet be ready, e.g.,
564   // when reading a version script.  We then default to
565   // --no-map-whole-files.
566   if (this->whole_file_view_ == NULL
567       && parameters->options_valid()
568       && parameters->options().map_whole_files())
569     this->whole_file_view_ = this->make_view(0, this->size_, 0, cache);
570 
571   // Try to find a View with the required BYTESHIFT.
572   File_read::View* vshifted;
573   File_read::View* v = this->find_view(offset + start, size,
574 				       aligned ? byteshift : -1U,
575 				       &vshifted);
576   if (v != NULL)
577     {
578       if (cache)
579 	v->set_cache();
580       return v;
581     }
582 
583   // If VSHIFTED is not NULL, then it has the data we need, but with
584   // the wrong byteshift.
585   v = vshifted;
586   if (v != NULL)
587     {
588       gold_assert(aligned);
589 
590       unsigned char* pbytes;
591       pbytes = static_cast<unsigned char*>(malloc(v->size() + byteshift));
592       if (pbytes == NULL)
593 	gold_nomem();
594       memset(pbytes, 0, byteshift);
595       memcpy(pbytes + byteshift, v->data() + v->byteshift(), v->size());
596 
597       File_read::View* shifted_view =
598 	  new File_read::View(v->start(), v->size(), pbytes, byteshift,
599 			      cache, View::DATA_ALLOCATED_ARRAY);
600 
601       this->add_view(shifted_view);
602       return shifted_view;
603     }
604 
605   // Make a new view.  If we don't need an aligned view, use a
606   // byteshift of 0, so that we can use mmap.
607   return this->make_view(offset + start, size,
608 			 aligned ? byteshift : 0,
609 			 cache);
610 }
611 
612 // Get a view into the file.
613 
614 const unsigned char*
get_view(off_t offset,off_t start,section_size_type size,bool aligned,bool cache)615 File_read::get_view(off_t offset, off_t start, section_size_type size,
616 		    bool aligned, bool cache)
617 {
618   File_read::View* pv = this->find_or_make_view(offset, start, size,
619 						aligned, cache);
620   return pv->data() + (offset + start - pv->start() + pv->byteshift());
621 }
622 
623 File_view*
get_lasting_view(off_t offset,off_t start,section_size_type size,bool aligned,bool cache)624 File_read::get_lasting_view(off_t offset, off_t start, section_size_type size,
625 			    bool aligned, bool cache)
626 {
627   File_read::View* pv = this->find_or_make_view(offset, start, size,
628 						aligned, cache);
629   pv->lock();
630   return new File_view(*this, pv,
631 		       (pv->data()
632 			+ (offset + start - pv->start() + pv->byteshift())));
633 }
634 
635 // Use readv to read COUNT entries from RM starting at START.  BASE
636 // must be added to all file offsets in RM.
637 
638 void
do_readv(off_t base,const Read_multiple & rm,size_t start,size_t count)639 File_read::do_readv(off_t base, const Read_multiple& rm, size_t start,
640 		    size_t count)
641 {
642   unsigned char discard[File_read::page_size];
643   iovec iov[File_read::max_readv_entries * 2];
644   size_t iov_index = 0;
645 
646   off_t first_offset = rm[start].file_offset;
647   off_t last_offset = first_offset;
648   ssize_t want = 0;
649   for (size_t i = 0; i < count; ++i)
650     {
651       const Read_multiple_entry& i_entry(rm[start + i]);
652 
653       if (i_entry.file_offset > last_offset)
654 	{
655 	  size_t skip = i_entry.file_offset - last_offset;
656 	  gold_assert(skip <= sizeof discard);
657 
658 	  iov[iov_index].iov_base = discard;
659 	  iov[iov_index].iov_len = skip;
660 	  ++iov_index;
661 
662 	  want += skip;
663 	}
664 
665       iov[iov_index].iov_base = i_entry.buffer;
666       iov[iov_index].iov_len = i_entry.size;
667       ++iov_index;
668 
669       want += i_entry.size;
670 
671       last_offset = i_entry.file_offset + i_entry.size;
672     }
673 
674   this->reopen_descriptor();
675 
676   gold_assert(iov_index < sizeof iov / sizeof iov[0]);
677 
678   if (::lseek(this->descriptor_, base + first_offset, SEEK_SET) < 0)
679     gold_fatal(_("%s: lseek failed: %s"),
680 	       this->filename().c_str(), strerror(errno));
681 
682   ssize_t got = ::readv(this->descriptor_, iov, iov_index);
683 
684   if (got < 0)
685     gold_fatal(_("%s: readv failed: %s"),
686 	       this->filename().c_str(), strerror(errno));
687   if (got != want)
688     gold_fatal(_("%s: file too short: read only %zd of %zd bytes at %lld"),
689 	       this->filename().c_str(),
690 	       got, want, static_cast<long long>(base + first_offset));
691 }
692 
693 // Portable IOV_MAX.
694 
695 #if !defined(HAVE_READV)
696 #define GOLD_IOV_MAX 1
697 #elif defined(IOV_MAX)
698 #define GOLD_IOV_MAX IOV_MAX
699 #else
700 #define GOLD_IOV_MAX (File_read::max_readv_entries * 2)
701 #endif
702 
703 // Read several pieces of data from the file.
704 
705 void
read_multiple(off_t base,const Read_multiple & rm)706 File_read::read_multiple(off_t base, const Read_multiple& rm)
707 {
708   static size_t iov_max = GOLD_IOV_MAX;
709   size_t count = rm.size();
710   size_t i = 0;
711   while (i < count)
712     {
713       // Find up to MAX_READV_ENTRIES consecutive entries which are
714       // less than one page apart.
715       const Read_multiple_entry& i_entry(rm[i]);
716       off_t i_off = i_entry.file_offset;
717       off_t end_off = i_off + i_entry.size;
718       size_t j;
719       for (j = i + 1; j < count; ++j)
720 	{
721 	  if (j - i >= File_read::max_readv_entries || j - i >= iov_max / 2)
722 	    break;
723 	  const Read_multiple_entry& j_entry(rm[j]);
724 	  off_t j_off = j_entry.file_offset;
725 	  gold_assert(j_off >= end_off);
726 	  off_t j_end_off = j_off + j_entry.size;
727 	  if (j_end_off - end_off >= File_read::page_size)
728 	    break;
729 	  end_off = j_end_off;
730 	}
731 
732       if (j == i + 1)
733 	this->read(base + i_off, i_entry.size, i_entry.buffer);
734       else
735 	{
736 	  File_read::View* view = this->find_view(base + i_off,
737 						  end_off - i_off,
738 						  -1U, NULL);
739 	  if (view == NULL)
740 	    this->do_readv(base, rm, i, j - i);
741 	  else
742 	    {
743 	      const unsigned char* v = (view->data()
744 					+ (base + i_off - view->start()
745 					   + view->byteshift()));
746 	      for (size_t k = i; k < j; ++k)
747 		{
748 		  const Read_multiple_entry& k_entry(rm[k]);
749 		  gold_assert((convert_to_section_size_type(k_entry.file_offset
750 							   - i_off)
751 			       + k_entry.size)
752 			      <= convert_to_section_size_type(end_off
753 							      - i_off));
754 		  memcpy(k_entry.buffer,
755 			 v + (k_entry.file_offset - i_off),
756 			 k_entry.size);
757 		}
758 	    }
759 	}
760 
761       i = j;
762     }
763 }
764 
765 // Mark all views as no longer cached.
766 
767 void
clear_view_cache_marks()768 File_read::clear_view_cache_marks()
769 {
770   // Just ignore this if there are multiple objects associated with
771   // the file.  Otherwise we will wind up uncaching and freeing some
772   // views for other objects.
773   if (this->object_count_ > 1)
774     return;
775 
776   for (Views::iterator p = this->views_.begin();
777        p != this->views_.end();
778        ++p)
779     p->second->clear_cache();
780   for (Saved_views::iterator p = this->saved_views_.begin();
781        p != this->saved_views_.end();
782        ++p)
783     (*p)->clear_cache();
784 }
785 
786 // Remove all the file views.  For a file which has multiple
787 // associated objects (i.e., an archive), we keep accessed views
788 // around until next time, in the hopes that they will be useful for
789 // the next object.
790 
791 void
clear_views(Clear_views_mode mode)792 File_read::clear_views(Clear_views_mode mode)
793 {
794   bool keep_files_mapped = (parameters->options_valid()
795 			    && parameters->options().keep_files_mapped());
796   Views::iterator p = this->views_.begin();
797   while (p != this->views_.end())
798     {
799       bool should_delete;
800       if (p->second->is_locked() || p->second->is_permanent_view())
801 	should_delete = false;
802       else if (mode == CLEAR_VIEWS_ALL)
803 	should_delete = true;
804       else if ((p->second->should_cache()
805 		|| p->second == this->whole_file_view_)
806 	       && keep_files_mapped)
807 	should_delete = false;
808       else if (this->object_count_ > 1
809 	       && p->second->accessed()
810 	       && mode != CLEAR_VIEWS_ARCHIVE)
811 	should_delete = false;
812       else
813 	should_delete = true;
814 
815       if (should_delete)
816 	{
817 	  if (p->second == this->whole_file_view_)
818 	    this->whole_file_view_ = NULL;
819 	  delete p->second;
820 
821 	  // map::erase invalidates only the iterator to the deleted
822 	  // element.
823 	  Views::iterator pe = p;
824 	  ++p;
825 	  this->views_.erase(pe);
826 	}
827       else
828 	{
829 	  p->second->clear_accessed();
830 	  ++p;
831 	}
832     }
833 
834   Saved_views::iterator q = this->saved_views_.begin();
835   while (q != this->saved_views_.end())
836     {
837       if (!(*q)->is_locked())
838 	{
839 	  delete *q;
840 	  q = this->saved_views_.erase(q);
841 	}
842       else
843 	{
844 	  gold_assert(mode != CLEAR_VIEWS_ALL);
845 	  ++q;
846 	}
847     }
848 }
849 
850 // Print statistical information to stderr.  This is used for --stats.
851 
852 void
print_stats()853 File_read::print_stats()
854 {
855   fprintf(stderr, _("%s: total bytes mapped for read: %llu\n"),
856 	  program_name, File_read::total_mapped_bytes);
857   fprintf(stderr, _("%s: maximum bytes mapped for read at one time: %llu\n"),
858 	  program_name, File_read::maximum_mapped_bytes);
859 }
860 
861 // Class File_view.
862 
~File_view()863 File_view::~File_view()
864 {
865   gold_assert(this->file_.is_locked());
866   this->view_->unlock();
867 }
868 
869 // Class Input_file.
870 
871 // Create a file given just the filename.
872 
Input_file(const char * name)873 Input_file::Input_file(const char* name)
874   : found_name_(), file_(), is_in_sysroot_(false), format_(FORMAT_NONE)
875 {
876   this->input_argument_ =
877     new Input_file_argument(name, Input_file_argument::INPUT_FILE_TYPE_FILE,
878 			    "", false, Position_dependent_options());
879 }
880 
881 // Create a file for testing.
882 
Input_file(const Task * task,const char * name,const unsigned char * contents,off_t size)883 Input_file::Input_file(const Task* task, const char* name,
884 		       const unsigned char* contents, off_t size)
885   : file_()
886 {
887   this->input_argument_ =
888     new Input_file_argument(name, Input_file_argument::INPUT_FILE_TYPE_FILE,
889 			    "", false, Position_dependent_options());
890   bool ok = this->file_.open(task, name, contents, size);
891   gold_assert(ok);
892 }
893 
894 // Return the position dependent options in force for this file.
895 
896 const Position_dependent_options&
options() const897 Input_file::options() const
898 {
899   return this->input_argument_->options();
900 }
901 
902 // Return the name given by the user.  For -lc this will return "c".
903 
904 const char*
name() const905 Input_file::name() const
906 {
907   return this->input_argument_->name();
908 }
909 
910 // Return whether this file is in a system directory.
911 
912 bool
is_in_system_directory() const913 Input_file::is_in_system_directory() const
914 {
915   if (this->is_in_sysroot())
916     return true;
917   return parameters->options().is_in_system_directory(this->filename());
918 }
919 
920 // Return whether we are only reading symbols.
921 
922 bool
just_symbols() const923 Input_file::just_symbols() const
924 {
925   return this->input_argument_->just_symbols();
926 }
927 
928 // Return whether this is a file that we will search for in the list
929 // of directories.
930 
931 bool
will_search_for() const932 Input_file::will_search_for() const
933 {
934   return (!IS_ABSOLUTE_PATH(this->input_argument_->name())
935 	  && (this->input_argument_->is_lib()
936 	      || this->input_argument_->is_searched_file()
937 	      || this->input_argument_->extra_search_path() != NULL));
938 }
939 
940 // Return the file last modification time.  Calls gold_fatal if the stat
941 // system call failed.
942 
943 Timespec
get_mtime()944 File_read::get_mtime()
945 {
946   struct stat file_stat;
947   this->reopen_descriptor();
948 
949   if (fstat(this->descriptor_, &file_stat) < 0)
950     gold_fatal(_("%s: stat failed: %s"), this->name_.c_str(),
951 	       strerror(errno));
952 #ifdef HAVE_STAT_ST_MTIM
953   return Timespec(file_stat.st_mtim.tv_sec, file_stat.st_mtim.tv_nsec);
954 #else
955   return Timespec(file_stat.st_mtime, 0);
956 #endif
957 }
958 
959 // Try to find a file in the extra search dirs.  Returns true on success.
960 
961 bool
try_extra_search_path(int * pindex,const Input_file_argument * input_argument,std::string filename,std::string * found_name,std::string * namep)962 Input_file::try_extra_search_path(int* pindex,
963 				  const Input_file_argument* input_argument,
964 				  std::string filename, std::string* found_name,
965 				  std::string* namep)
966 {
967   if (input_argument->extra_search_path() == NULL)
968     return false;
969 
970   std::string name = input_argument->extra_search_path();
971   if (!IS_DIR_SEPARATOR(name[name.length() - 1]))
972     name += '/';
973   name += filename;
974 
975   struct stat dummy_stat;
976   if (*pindex > 0 || ::stat(name.c_str(), &dummy_stat) < 0)
977     return false;
978 
979   *found_name = filename;
980   *namep = name;
981   return true;
982 }
983 
984 // Find the actual file.
985 // If the filename is not absolute, we assume it is in the current
986 // directory *except* when:
987 //    A) input_argument_->is_lib() is true;
988 //    B) input_argument_->is_searched_file() is true; or
989 //    C) input_argument_->extra_search_path() is not empty.
990 // In each, we look in extra_search_path + library_path to find
991 // the file location, rather than the current directory.
992 
993 bool
find_file(const Dirsearch & dirpath,int * pindex,const Input_file_argument * input_argument,bool * is_in_sysroot,std::string * found_name,std::string * namep)994 Input_file::find_file(const Dirsearch& dirpath, int* pindex,
995 		      const Input_file_argument* input_argument,
996 		      bool* is_in_sysroot,
997 		      std::string* found_name, std::string* namep)
998 {
999   std::string name;
1000 
1001   // Case 1: name is an absolute file, just try to open it
1002   // Case 2: name is relative but is_lib is false, is_searched_file is false,
1003   //         and extra_search_path is empty
1004   if (IS_ABSOLUTE_PATH(input_argument->name())
1005       || (!input_argument->is_lib()
1006 	  && !input_argument->is_searched_file()
1007 	  && input_argument->extra_search_path() == NULL))
1008     {
1009       name = input_argument->name();
1010       *found_name = name;
1011       *namep = name;
1012       return true;
1013     }
1014   // Case 3: is_lib is true or is_searched_file is true
1015   else if (input_argument->is_lib()
1016 	   || input_argument->is_searched_file())
1017     {
1018       std::vector<std::string> names;
1019       names.reserve(2);
1020       if (input_argument->is_lib())
1021 	{
1022 	  std::string prefix = "lib";
1023 	  prefix += input_argument->name();
1024 	  if (parameters->options().is_static()
1025 	      || !input_argument->options().Bdynamic())
1026 	    names.push_back(prefix + ".a");
1027 	  else
1028 	    {
1029 	      names.push_back(prefix + ".so");
1030 	      names.push_back(prefix + ".a");
1031 	    }
1032 	}
1033       else
1034 	names.push_back(input_argument->name());
1035 
1036       for (std::vector<std::string>::const_iterator n = names.begin();
1037 	   n != names.end();
1038 	   ++n)
1039 	if (Input_file::try_extra_search_path(pindex, input_argument, *n,
1040 					      found_name, namep))
1041 	  return true;
1042 
1043       // It is not in the extra_search_path.
1044       name = dirpath.find(names, is_in_sysroot, pindex, found_name);
1045       if (name.empty())
1046 	{
1047 	  gold_error(_("cannot find %s%s"),
1048 		     input_argument->is_lib() ? "-l" : "",
1049 		     input_argument->name());
1050 	  return false;
1051 	}
1052       *namep = name;
1053       return true;
1054     }
1055   // Case 4: extra_search_path is not empty
1056   else
1057     {
1058       gold_assert(input_argument->extra_search_path() != NULL);
1059 
1060       if (try_extra_search_path(pindex, input_argument, input_argument->name(),
1061 				found_name, namep))
1062 	return true;
1063 
1064       // extra_search_path failed, so check the normal search-path.
1065       int index = *pindex;
1066       if (index > 0)
1067 	--index;
1068       name = dirpath.find(std::vector<std::string>(1, input_argument->name()),
1069 			  is_in_sysroot, &index, found_name);
1070       if (name.empty())
1071 	{
1072 	  gold_error(_("cannot find %s"),
1073 		     input_argument->name());
1074 	  return false;
1075 	}
1076       *namep = name;
1077       *pindex = index + 1;
1078       return true;
1079     }
1080 }
1081 
1082 // Open the file.
1083 
1084 bool
open(const Dirsearch & dirpath,const Task * task,int * pindex)1085 Input_file::open(const Dirsearch& dirpath, const Task* task, int* pindex)
1086 {
1087   std::string name;
1088   if (!Input_file::find_file(dirpath, pindex, this->input_argument_,
1089 			     &this->is_in_sysroot_, &this->found_name_, &name))
1090     return false;
1091 
1092   // Now that we've figured out where the file lives, try to open it.
1093 
1094   General_options::Object_format format =
1095     this->input_argument_->options().format_enum();
1096   bool ok;
1097   if (format == General_options::OBJECT_FORMAT_ELF)
1098     {
1099       ok = this->file_.open(task, name);
1100       this->format_ = FORMAT_ELF;
1101     }
1102   else
1103     {
1104       gold_assert(format == General_options::OBJECT_FORMAT_BINARY);
1105       ok = this->open_binary(task, name);
1106       this->format_ = FORMAT_BINARY;
1107     }
1108 
1109   if (!ok)
1110     {
1111       gold_error(_("cannot open %s: %s"),
1112 		 name.c_str(), strerror(errno));
1113       this->format_ = FORMAT_NONE;
1114       return false;
1115     }
1116 
1117   return true;
1118 }
1119 
1120 // Open a file for --format binary.
1121 
1122 bool
open_binary(const Task * task,const std::string & name)1123 Input_file::open_binary(const Task* task, const std::string& name)
1124 {
1125   // In order to open a binary file, we need machine code, size, and
1126   // endianness.  We may not have a valid target at this point, in
1127   // which case we use the default target.
1128   parameters_force_valid_target();
1129   const Target& target(parameters->target());
1130 
1131   Binary_to_elf binary_to_elf(target.machine_code(),
1132 			      target.get_size(),
1133 			      target.is_big_endian(),
1134 			      name);
1135   if (!binary_to_elf.convert(task))
1136     return false;
1137   return this->file_.open(task, name, binary_to_elf.converted_data_leak(),
1138 			  binary_to_elf.converted_size());
1139 }
1140 
1141 } // End namespace gold.
1142