xref: /netbsd/external/gpl3/gdb/dist/gold/fileread.cc (revision 1424dfb3)
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 std::vector<std::string> File_read::files_read;
128 
129 // Class File_read::View.
130 
~View()131 File_read::View::~View()
132 {
133   gold_assert(!this->is_locked());
134   switch (this->data_ownership_)
135     {
136     case DATA_ALLOCATED_ARRAY:
137       free(const_cast<unsigned char*>(this->data_));
138       break;
139     case DATA_MMAPPED:
140       if (::munmap(const_cast<unsigned char*>(this->data_), this->size_) != 0)
141 	gold_warning(_("munmap failed: %s"), strerror(errno));
142       if (!parameters->options_valid() || parameters->options().stats())
143 	{
144 	  file_counts_initialize_lock.initialize();
145 	  Hold_optional_lock hl(file_counts_lock);
146 	  File_read::current_mapped_bytes -= this->size_;
147 	}
148       break;
149     case DATA_NOT_OWNED:
150       break;
151     default:
152       gold_unreachable();
153     }
154 }
155 
156 void
lock()157 File_read::View::lock()
158 {
159   ++this->lock_count_;
160 }
161 
162 void
unlock()163 File_read::View::unlock()
164 {
165   gold_assert(this->lock_count_ > 0);
166   --this->lock_count_;
167 }
168 
169 bool
is_locked()170 File_read::View::is_locked()
171 {
172   return this->lock_count_ > 0;
173 }
174 
175 // Class File_read.
176 
~File_read()177 File_read::~File_read()
178 {
179   gold_assert(this->token_.is_writable());
180   if (this->is_descriptor_opened_)
181     {
182       release_descriptor(this->descriptor_, true);
183       this->descriptor_ = -1;
184       this->is_descriptor_opened_ = false;
185     }
186   this->name_.clear();
187   this->clear_views(CLEAR_VIEWS_ALL);
188 }
189 
190 // Open the file.
191 
192 bool
open(const Task * task,const std::string & name)193 File_read::open(const Task* task, const std::string& name)
194 {
195   gold_assert(this->token_.is_writable()
196 	      && this->descriptor_ < 0
197 	      && !this->is_descriptor_opened_
198 	      && this->name_.empty());
199   this->name_ = name;
200 
201   this->descriptor_ = open_descriptor(-1, this->name_.c_str(),
202 				      O_RDONLY);
203 
204   if (this->descriptor_ >= 0)
205     {
206       this->is_descriptor_opened_ = true;
207       struct stat s;
208       if (::fstat(this->descriptor_, &s) < 0)
209 	gold_error(_("%s: fstat failed: %s"),
210 		   this->name_.c_str(), strerror(errno));
211       this->size_ = s.st_size;
212       gold_debug(DEBUG_FILES, "Attempt to open %s succeeded",
213 		 this->name_.c_str());
214       this->token_.add_writer(task);
215       Hold_optional_lock hl(file_counts_lock);
216       record_file_read(this->name_);
217     }
218 
219   return this->descriptor_ >= 0;
220 }
221 
222 // Open the file with the contents in memory.
223 
224 bool
open(const Task * task,const std::string & name,const unsigned char * contents,off_t size)225 File_read::open(const Task* task, const std::string& name,
226 		const unsigned char* contents, off_t size)
227 {
228   gold_assert(this->token_.is_writable()
229 	      && this->descriptor_ < 0
230 	      && !this->is_descriptor_opened_
231 	      && this->name_.empty());
232   this->name_ = name;
233   this->whole_file_view_ = new View(0, size, contents, 0, false,
234 				    View::DATA_NOT_OWNED);
235   this->add_view(this->whole_file_view_);
236   this->size_ = size;
237   this->token_.add_writer(task);
238   return true;
239 }
240 
241 // Reopen a descriptor if necessary.
242 
243 void
reopen_descriptor()244 File_read::reopen_descriptor()
245 {
246   if (!this->is_descriptor_opened_)
247     {
248       this->descriptor_ = open_descriptor(this->descriptor_,
249 					  this->name_.c_str(),
250 					  O_RDONLY);
251       if (this->descriptor_ < 0)
252 	gold_fatal(_("could not reopen file %s"), this->name_.c_str());
253       this->is_descriptor_opened_ = true;
254     }
255 }
256 
257 // Release the file.  This is called when we are done with the file in
258 // a Task.
259 
260 void
release()261 File_read::release()
262 {
263   gold_assert(this->is_locked());
264 
265   if (!parameters->options_valid() || parameters->options().stats())
266     {
267       file_counts_initialize_lock.initialize();
268       Hold_optional_lock hl(file_counts_lock);
269       File_read::total_mapped_bytes += this->mapped_bytes_;
270       File_read::current_mapped_bytes += this->mapped_bytes_;
271       if (File_read::current_mapped_bytes > File_read::maximum_mapped_bytes)
272 	File_read::maximum_mapped_bytes = File_read::current_mapped_bytes;
273     }
274 
275   this->mapped_bytes_ = 0;
276 
277   // Only clear views if there is only one attached object.  Otherwise
278   // we waste time trying to clear cached archive views.  Similarly
279   // for releasing the descriptor.
280   if (this->object_count_ <= 1)
281     {
282       this->clear_views(CLEAR_VIEWS_NORMAL);
283       if (this->is_descriptor_opened_)
284 	{
285 	  release_descriptor(this->descriptor_, false);
286 	  this->is_descriptor_opened_ = false;
287 	}
288     }
289 
290   this->released_ = true;
291 }
292 
293 // Lock the file.
294 
295 void
lock(const Task * task)296 File_read::lock(const Task* task)
297 {
298   gold_assert(this->released_);
299   gold_debug(DEBUG_FILES, "Locking file \"%s\"", this->name_.c_str());
300   this->token_.add_writer(task);
301   this->released_ = false;
302 }
303 
304 // Unlock the file.
305 
306 void
unlock(const Task * task)307 File_read::unlock(const Task* task)
308 {
309   gold_debug(DEBUG_FILES, "Unlocking file \"%s\"", this->name_.c_str());
310   this->release();
311   this->token_.remove_writer(task);
312 }
313 
314 // Return whether the file is locked.
315 
316 bool
is_locked() const317 File_read::is_locked() const
318 {
319   if (!this->token_.is_writable())
320     return true;
321   // The file is not locked, so it should have been released.
322   gold_assert(this->released_);
323   return false;
324 }
325 
326 // See if we have a view which covers the file starting at START for
327 // SIZE bytes.  Return a pointer to the View if found, NULL if not.
328 // If BYTESHIFT is not -1U, the returned View must have the specified
329 // byte shift; otherwise, it may have any byte shift.  If VSHIFTED is
330 // not NULL, this sets *VSHIFTED to a view which would have worked if
331 // not for the requested BYTESHIFT.
332 
333 inline File_read::View*
find_view(off_t start,section_size_type size,unsigned int byteshift,File_read::View ** vshifted) const334 File_read::find_view(off_t start, section_size_type size,
335 		     unsigned int byteshift, File_read::View** vshifted) const
336 {
337   gold_assert(start <= this->size_
338 	      && (static_cast<unsigned long long>(size)
339 		  <= static_cast<unsigned long long>(this->size_ - start)));
340 
341   if (vshifted != NULL)
342     *vshifted = NULL;
343 
344   // If we have the whole file mmapped, and the alignment is right,
345   // we can return it.
346   if (this->whole_file_view_)
347     if (byteshift == -1U || byteshift == 0)
348       return this->whole_file_view_;
349 
350   off_t page = File_read::page_offset(start);
351 
352   unsigned int bszero = 0;
353   Views::const_iterator p = this->views_.upper_bound(std::make_pair(page - 1,
354 								    bszero));
355 
356   while (p != this->views_.end() && p->first.first <= page)
357     {
358       if (p->second->start() <= start
359 	  && (p->second->start() + static_cast<off_t>(p->second->size())
360 	      >= start + static_cast<off_t>(size)))
361 	{
362 	  if (byteshift == -1U || byteshift == p->second->byteshift())
363 	    {
364 	      p->second->set_accessed();
365 	      return p->second;
366 	    }
367 
368 	  if (vshifted != NULL && *vshifted == NULL)
369 	    *vshifted = p->second;
370 	}
371 
372       ++p;
373     }
374 
375   return NULL;
376 }
377 
378 // Read SIZE bytes from the file starting at offset START.  Read into
379 // the buffer at P.
380 
381 void
do_read(off_t start,section_size_type size,void * p)382 File_read::do_read(off_t start, section_size_type size, void* p)
383 {
384   ssize_t bytes;
385   if (this->whole_file_view_ != NULL)
386     {
387       bytes = this->size_ - start;
388       if (static_cast<section_size_type>(bytes) >= size)
389 	{
390 	  memcpy(p, this->whole_file_view_->data() + start, size);
391 	  return;
392 	}
393     }
394   else
395     {
396       this->reopen_descriptor();
397 
398       char *read_ptr = static_cast<char *>(p);
399       off_t read_pos = start;
400       size_t to_read = size;
401       do
402 	{
403 	  bytes = ::pread(this->descriptor_, read_ptr, to_read, read_pos);
404 	  if (bytes < 0)
405 	    gold_fatal(_("%s: pread failed: %s"),
406 		       this->filename().c_str(), strerror(errno));
407 
408 	  read_pos += bytes;
409 	  read_ptr += bytes;
410 	  to_read -= bytes;
411 	  if (to_read == 0)
412 	    return;
413 	}
414       while (bytes > 0);
415 
416       bytes = size - to_read;
417     }
418 
419   gold_fatal(_("%s: file too short: read only %lld of %lld bytes at %lld"),
420 	     this->filename().c_str(),
421 	     static_cast<long long>(bytes),
422 	     static_cast<long long>(size),
423 	     static_cast<long long>(start));
424 }
425 
426 // Read data from the file.
427 
428 void
read(off_t start,section_size_type size,void * p)429 File_read::read(off_t start, section_size_type size, void* p)
430 {
431   const File_read::View* pv = this->find_view(start, size, -1U, NULL);
432   if (pv != NULL)
433     {
434       memcpy(p, pv->data() + (start - pv->start() + pv->byteshift()), size);
435       return;
436     }
437 
438   this->do_read(start, size, p);
439 }
440 
441 // Add a new view.  There may already be an existing view at this
442 // offset.  If there is, the new view will be larger, and should
443 // replace the old view.
444 
445 void
add_view(File_read::View * v)446 File_read::add_view(File_read::View* v)
447 {
448   std::pair<Views::iterator, bool> ins =
449     this->views_.insert(std::make_pair(std::make_pair(v->start(),
450 						      v->byteshift()),
451 				       v));
452   if (ins.second)
453     return;
454 
455   // There was an existing view at this offset.  It must not be large
456   // enough.  We can't delete it here, since something might be using
457   // it; we put it on a list to be deleted when the file is unlocked.
458   File_read::View* vold = ins.first->second;
459   gold_assert(vold->size() < v->size());
460   if (vold->should_cache())
461     {
462       v->set_cache();
463       vold->clear_cache();
464     }
465   this->saved_views_.push_back(vold);
466 
467   ins.first->second = v;
468 }
469 
470 // Make a new view with a specified byteshift, reading the data from
471 // the file.
472 
473 File_read::View*
make_view(off_t start,section_size_type size,unsigned int byteshift,bool cache)474 File_read::make_view(off_t start, section_size_type size,
475 		     unsigned int byteshift, bool cache)
476 {
477   gold_assert(size > 0);
478   gold_assert(start <= this->size_
479 	      && (static_cast<unsigned long long>(size)
480 		  <= static_cast<unsigned long long>(this->size_ - start)));
481 
482   off_t poff = File_read::page_offset(start);
483 
484   section_size_type psize = File_read::pages(size + (start - poff));
485 
486   if (poff + static_cast<off_t>(psize) >= this->size_)
487     {
488       psize = this->size_ - poff;
489       gold_assert(psize >= size);
490     }
491 
492   void* p;
493   View::Data_ownership ownership;
494   if (byteshift != 0)
495     {
496       p = malloc(psize + byteshift);
497       if (p == NULL)
498 	gold_nomem();
499       memset(p, 0, byteshift);
500       this->do_read(poff, psize, static_cast<unsigned char*>(p) + byteshift);
501       ownership = View::DATA_ALLOCATED_ARRAY;
502     }
503   else
504     {
505       this->reopen_descriptor();
506       p = ::mmap(NULL, psize, PROT_READ, MAP_PRIVATE, this->descriptor_, poff);
507       if (p != MAP_FAILED)
508 	{
509 	  ownership = View::DATA_MMAPPED;
510 	  this->mapped_bytes_ += psize;
511 	}
512       else
513 	{
514 	  p = malloc(psize);
515 	  if (p == NULL)
516 	    gold_nomem();
517 	  this->do_read(poff, psize, p);
518 	  ownership = View::DATA_ALLOCATED_ARRAY;
519 	}
520     }
521 
522   const unsigned char* pbytes = static_cast<const unsigned char*>(p);
523   File_read::View* v = new File_read::View(poff, psize, pbytes, byteshift,
524 					   cache, ownership);
525 
526   this->add_view(v);
527 
528   return v;
529 }
530 
531 // Find a View or make a new one, shifted as required by the file
532 // offset OFFSET and ALIGNED.
533 
534 File_read::View*
find_or_make_view(off_t offset,off_t start,section_size_type size,bool aligned,bool cache)535 File_read::find_or_make_view(off_t offset, off_t start,
536 			     section_size_type size, bool aligned, bool cache)
537 {
538   // Check that start and end of the view are within the file.
539   if (start > this->size_
540       || (static_cast<unsigned long long>(size)
541 	  > static_cast<unsigned long long>(this->size_ - start)))
542     gold_fatal(_("%s: attempt to map %lld bytes at offset %lld exceeds "
543 		 "size of file; the file may be corrupt"),
544 		   this->filename().c_str(),
545 		   static_cast<long long>(size),
546 		   static_cast<long long>(start));
547 
548   unsigned int byteshift;
549   if (offset == 0)
550     byteshift = 0;
551   else
552     {
553       unsigned int target_size = (!parameters->target_valid()
554 				  ? 64
555 				  : parameters->target().get_size());
556       byteshift = offset & ((target_size / 8) - 1);
557 
558       // Set BYTESHIFT to the number of dummy bytes which must be
559       // inserted before the data in order for this data to be
560       // aligned.
561       if (byteshift != 0)
562 	byteshift = (target_size / 8) - byteshift;
563     }
564 
565   // If --map-whole-files is set, make sure we have a
566   // whole file view.  Options may not yet be ready, e.g.,
567   // when reading a version script.  We then default to
568   // --no-map-whole-files.
569   if (this->whole_file_view_ == NULL
570       && parameters->options_valid()
571       && parameters->options().map_whole_files())
572     this->whole_file_view_ = this->make_view(0, this->size_, 0, cache);
573 
574   // Try to find a View with the required BYTESHIFT.
575   File_read::View* vshifted;
576   File_read::View* v = this->find_view(offset + start, size,
577 				       aligned ? byteshift : -1U,
578 				       &vshifted);
579   if (v != NULL)
580     {
581       if (cache)
582 	v->set_cache();
583       return v;
584     }
585 
586   // If VSHIFTED is not NULL, then it has the data we need, but with
587   // the wrong byteshift.
588   v = vshifted;
589   if (v != NULL)
590     {
591       gold_assert(aligned);
592 
593       unsigned char* pbytes;
594       pbytes = static_cast<unsigned char*>(malloc(v->size() + byteshift));
595       if (pbytes == NULL)
596 	gold_nomem();
597       memset(pbytes, 0, byteshift);
598       memcpy(pbytes + byteshift, v->data() + v->byteshift(), v->size());
599 
600       File_read::View* shifted_view =
601 	  new File_read::View(v->start(), v->size(), pbytes, byteshift,
602 			      cache, View::DATA_ALLOCATED_ARRAY);
603 
604       this->add_view(shifted_view);
605       return shifted_view;
606     }
607 
608   // Make a new view.  If we don't need an aligned view, use a
609   // byteshift of 0, so that we can use mmap.
610   return this->make_view(offset + start, size,
611 			 aligned ? byteshift : 0,
612 			 cache);
613 }
614 
615 // Get a view into the file.
616 
617 const unsigned char*
get_view(off_t offset,off_t start,section_size_type size,bool aligned,bool cache)618 File_read::get_view(off_t offset, off_t start, section_size_type size,
619 		    bool aligned, bool cache)
620 {
621   File_read::View* pv = this->find_or_make_view(offset, start, size,
622 						aligned, cache);
623   return pv->data() + (offset + start - pv->start() + pv->byteshift());
624 }
625 
626 File_view*
get_lasting_view(off_t offset,off_t start,section_size_type size,bool aligned,bool cache)627 File_read::get_lasting_view(off_t offset, off_t start, section_size_type size,
628 			    bool aligned, bool cache)
629 {
630   File_read::View* pv = this->find_or_make_view(offset, start, size,
631 						aligned, cache);
632   pv->lock();
633   return new File_view(*this, pv,
634 		       (pv->data()
635 			+ (offset + start - pv->start() + pv->byteshift())));
636 }
637 
638 // Use readv to read COUNT entries from RM starting at START.  BASE
639 // must be added to all file offsets in RM.
640 
641 void
do_readv(off_t base,const Read_multiple & rm,size_t start,size_t count)642 File_read::do_readv(off_t base, const Read_multiple& rm, size_t start,
643 		    size_t count)
644 {
645   unsigned char discard[File_read::page_size];
646   iovec iov[File_read::max_readv_entries * 2];
647   size_t iov_index = 0;
648 
649   off_t first_offset = rm[start].file_offset;
650   off_t last_offset = first_offset;
651   ssize_t want = 0;
652   for (size_t i = 0; i < count; ++i)
653     {
654       const Read_multiple_entry& i_entry(rm[start + i]);
655 
656       if (i_entry.file_offset > last_offset)
657 	{
658 	  size_t skip = i_entry.file_offset - last_offset;
659 	  gold_assert(skip <= sizeof discard);
660 
661 	  iov[iov_index].iov_base = discard;
662 	  iov[iov_index].iov_len = skip;
663 	  ++iov_index;
664 
665 	  want += skip;
666 	}
667 
668       iov[iov_index].iov_base = i_entry.buffer;
669       iov[iov_index].iov_len = i_entry.size;
670       ++iov_index;
671 
672       want += i_entry.size;
673 
674       last_offset = i_entry.file_offset + i_entry.size;
675     }
676 
677   this->reopen_descriptor();
678 
679   gold_assert(iov_index < sizeof iov / sizeof iov[0]);
680 
681   if (::lseek(this->descriptor_, base + first_offset, SEEK_SET) < 0)
682     gold_fatal(_("%s: lseek failed: %s"),
683 	       this->filename().c_str(), strerror(errno));
684 
685   ssize_t got = ::readv(this->descriptor_, iov, iov_index);
686 
687   if (got < 0)
688     gold_fatal(_("%s: readv failed: %s"),
689 	       this->filename().c_str(), strerror(errno));
690   if (got != want)
691     gold_fatal(_("%s: file too short: read only %zd of %zd bytes at %lld"),
692 	       this->filename().c_str(),
693 	       got, want, static_cast<long long>(base + first_offset));
694 }
695 
696 // Portable IOV_MAX.
697 
698 #if !defined(HAVE_READV)
699 #define GOLD_IOV_MAX 1
700 #elif defined(IOV_MAX)
701 #define GOLD_IOV_MAX IOV_MAX
702 #else
703 #define GOLD_IOV_MAX (File_read::max_readv_entries * 2)
704 #endif
705 
706 // Read several pieces of data from the file.
707 
708 void
read_multiple(off_t base,const Read_multiple & rm)709 File_read::read_multiple(off_t base, const Read_multiple& rm)
710 {
711   static size_t iov_max = GOLD_IOV_MAX;
712   size_t count = rm.size();
713   size_t i = 0;
714   while (i < count)
715     {
716       // Find up to MAX_READV_ENTRIES consecutive entries which are
717       // less than one page apart.
718       const Read_multiple_entry& i_entry(rm[i]);
719       off_t i_off = i_entry.file_offset;
720       off_t end_off = i_off + i_entry.size;
721       size_t j;
722       for (j = i + 1; j < count; ++j)
723 	{
724 	  if (j - i >= File_read::max_readv_entries || j - i >= iov_max / 2)
725 	    break;
726 	  const Read_multiple_entry& j_entry(rm[j]);
727 	  off_t j_off = j_entry.file_offset;
728 	  gold_assert(j_off >= end_off);
729 	  off_t j_end_off = j_off + j_entry.size;
730 	  if (j_end_off - end_off >= File_read::page_size)
731 	    break;
732 	  end_off = j_end_off;
733 	}
734 
735       if (j == i + 1)
736 	this->read(base + i_off, i_entry.size, i_entry.buffer);
737       else
738 	{
739 	  File_read::View* view = this->find_view(base + i_off,
740 						  end_off - i_off,
741 						  -1U, NULL);
742 	  if (view == NULL)
743 	    this->do_readv(base, rm, i, j - i);
744 	  else
745 	    {
746 	      const unsigned char* v = (view->data()
747 					+ (base + i_off - view->start()
748 					   + view->byteshift()));
749 	      for (size_t k = i; k < j; ++k)
750 		{
751 		  const Read_multiple_entry& k_entry(rm[k]);
752 		  gold_assert((convert_to_section_size_type(k_entry.file_offset
753 							   - i_off)
754 			       + k_entry.size)
755 			      <= convert_to_section_size_type(end_off
756 							      - i_off));
757 		  memcpy(k_entry.buffer,
758 			 v + (k_entry.file_offset - i_off),
759 			 k_entry.size);
760 		}
761 	    }
762 	}
763 
764       i = j;
765     }
766 }
767 
768 // Mark all views as no longer cached.
769 
770 void
clear_view_cache_marks()771 File_read::clear_view_cache_marks()
772 {
773   // Just ignore this if there are multiple objects associated with
774   // the file.  Otherwise we will wind up uncaching and freeing some
775   // views for other objects.
776   if (this->object_count_ > 1)
777     return;
778 
779   for (Views::iterator p = this->views_.begin();
780        p != this->views_.end();
781        ++p)
782     p->second->clear_cache();
783   for (Saved_views::iterator p = this->saved_views_.begin();
784        p != this->saved_views_.end();
785        ++p)
786     (*p)->clear_cache();
787 }
788 
789 // Remove all the file views.  For a file which has multiple
790 // associated objects (i.e., an archive), we keep accessed views
791 // around until next time, in the hopes that they will be useful for
792 // the next object.
793 
794 void
clear_views(Clear_views_mode mode)795 File_read::clear_views(Clear_views_mode mode)
796 {
797   bool keep_files_mapped = (parameters->options_valid()
798 			    && parameters->options().keep_files_mapped());
799   Views::iterator p = this->views_.begin();
800   while (p != this->views_.end())
801     {
802       bool should_delete;
803       if (p->second->is_locked() || p->second->is_permanent_view())
804 	should_delete = false;
805       else if (mode == CLEAR_VIEWS_ALL)
806 	should_delete = true;
807       else if ((p->second->should_cache()
808 		|| p->second == this->whole_file_view_)
809 	       && keep_files_mapped)
810 	should_delete = false;
811       else if (this->object_count_ > 1
812 	       && p->second->accessed()
813 	       && mode != CLEAR_VIEWS_ARCHIVE)
814 	should_delete = false;
815       else
816 	should_delete = true;
817 
818       if (should_delete)
819 	{
820 	  if (p->second == this->whole_file_view_)
821 	    this->whole_file_view_ = NULL;
822 	  delete p->second;
823 
824 	  // map::erase invalidates only the iterator to the deleted
825 	  // element.
826 	  Views::iterator pe = p;
827 	  ++p;
828 	  this->views_.erase(pe);
829 	}
830       else
831 	{
832 	  p->second->clear_accessed();
833 	  ++p;
834 	}
835     }
836 
837   Saved_views::iterator q = this->saved_views_.begin();
838   while (q != this->saved_views_.end())
839     {
840       if (!(*q)->is_locked())
841 	{
842 	  delete *q;
843 	  q = this->saved_views_.erase(q);
844 	}
845       else
846 	{
847 	  gold_assert(mode != CLEAR_VIEWS_ALL);
848 	  ++q;
849 	}
850     }
851 }
852 
853 // Print statistical information to stderr.  This is used for --stats.
854 
855 void
print_stats()856 File_read::print_stats()
857 {
858   fprintf(stderr, _("%s: total bytes mapped for read: %llu\n"),
859 	  program_name, File_read::total_mapped_bytes);
860   fprintf(stderr, _("%s: maximum bytes mapped for read at one time: %llu\n"),
861 	  program_name, File_read::maximum_mapped_bytes);
862 }
863 
864 // Class File_view.
865 
~File_view()866 File_view::~File_view()
867 {
868   gold_assert(this->file_.is_locked());
869   this->view_->unlock();
870 }
871 
872 // Class Input_file.
873 
874 // Create a file given just the filename.
875 
Input_file(const char * name)876 Input_file::Input_file(const char* name)
877   : found_name_(), file_(), is_in_sysroot_(false), format_(FORMAT_NONE)
878 {
879   this->input_argument_ =
880     new Input_file_argument(name, Input_file_argument::INPUT_FILE_TYPE_FILE,
881 			    "", false, Position_dependent_options());
882 }
883 
884 // Create a file for testing.
885 
Input_file(const Task * task,const char * name,const unsigned char * contents,off_t size)886 Input_file::Input_file(const Task* task, const char* name,
887 		       const unsigned char* contents, off_t size)
888   : file_()
889 {
890   this->input_argument_ =
891     new Input_file_argument(name, Input_file_argument::INPUT_FILE_TYPE_FILE,
892 			    "", false, Position_dependent_options());
893   bool ok = this->file_.open(task, name, contents, size);
894   gold_assert(ok);
895 }
896 
897 // Return the position dependent options in force for this file.
898 
899 const Position_dependent_options&
options() const900 Input_file::options() const
901 {
902   return this->input_argument_->options();
903 }
904 
905 // Return the name given by the user.  For -lc this will return "c".
906 
907 const char*
name() const908 Input_file::name() const
909 {
910   return this->input_argument_->name();
911 }
912 
913 // Return whether this file is in a system directory.
914 
915 bool
is_in_system_directory() const916 Input_file::is_in_system_directory() const
917 {
918   if (this->is_in_sysroot())
919     return true;
920   return parameters->options().is_in_system_directory(this->filename());
921 }
922 
923 // Return whether we are only reading symbols.
924 
925 bool
just_symbols() const926 Input_file::just_symbols() const
927 {
928   return this->input_argument_->just_symbols();
929 }
930 
931 // Return whether this is a file that we will search for in the list
932 // of directories.
933 
934 bool
will_search_for() const935 Input_file::will_search_for() const
936 {
937   return (!IS_ABSOLUTE_PATH(this->input_argument_->name())
938 	  && (this->input_argument_->is_lib()
939 	      || this->input_argument_->is_searched_file()
940 	      || this->input_argument_->extra_search_path() != NULL));
941 }
942 
943 // Return the file last modification time.  Calls gold_fatal if the stat
944 // system call failed.
945 
946 Timespec
get_mtime()947 File_read::get_mtime()
948 {
949   struct stat file_stat;
950   this->reopen_descriptor();
951 
952   if (fstat(this->descriptor_, &file_stat) < 0)
953     gold_fatal(_("%s: stat failed: %s"), this->name_.c_str(),
954 	       strerror(errno));
955 #ifdef HAVE_STAT_ST_MTIM
956   return Timespec(file_stat.st_mtim.tv_sec, file_stat.st_mtim.tv_nsec);
957 #else
958   return Timespec(file_stat.st_mtime, 0);
959 #endif
960 }
961 
962 // Try to find a file in the extra search dirs.  Returns true on success.
963 
964 bool
try_extra_search_path(int * pindex,const Input_file_argument * input_argument,std::string filename,std::string * found_name,std::string * namep)965 Input_file::try_extra_search_path(int* pindex,
966 				  const Input_file_argument* input_argument,
967 				  std::string filename, std::string* found_name,
968 				  std::string* namep)
969 {
970   if (input_argument->extra_search_path() == NULL)
971     return false;
972 
973   std::string name = input_argument->extra_search_path();
974   if (!IS_DIR_SEPARATOR(name[name.length() - 1]))
975     name += '/';
976   name += filename;
977 
978   struct stat dummy_stat;
979   if (*pindex > 0 || ::stat(name.c_str(), &dummy_stat) < 0)
980     return false;
981 
982   *found_name = filename;
983   *namep = name;
984   return true;
985 }
986 
987 // Find the actual file.
988 // If the filename is not absolute, we assume it is in the current
989 // directory *except* when:
990 //    A) input_argument_->is_lib() is true;
991 //    B) input_argument_->is_searched_file() is true; or
992 //    C) input_argument_->extra_search_path() is not empty.
993 // In each, we look in extra_search_path + library_path to find
994 // the file location, rather than the current directory.
995 
996 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)997 Input_file::find_file(const Dirsearch& dirpath, int* pindex,
998 		      const Input_file_argument* input_argument,
999 		      bool* is_in_sysroot,
1000 		      std::string* found_name, std::string* namep)
1001 {
1002   std::string name;
1003 
1004   // Case 1: name is an absolute file, just try to open it
1005   // Case 2: name is relative but is_lib is false, is_searched_file is false,
1006   //         and extra_search_path is empty
1007   if (IS_ABSOLUTE_PATH(input_argument->name())
1008       || (!input_argument->is_lib()
1009 	  && !input_argument->is_searched_file()
1010 	  && input_argument->extra_search_path() == NULL))
1011     {
1012       name = input_argument->name();
1013       *found_name = name;
1014       *namep = name;
1015       return true;
1016     }
1017   // Case 3: is_lib is true or is_searched_file is true
1018   else if (input_argument->is_lib()
1019 	   || input_argument->is_searched_file())
1020     {
1021       std::vector<std::string> names;
1022       names.reserve(2);
1023       if (input_argument->is_lib())
1024 	{
1025 	  std::string prefix = "lib";
1026 	  prefix += input_argument->name();
1027 	  if (parameters->options().is_static()
1028 	      || !input_argument->options().Bdynamic())
1029 	    names.push_back(prefix + ".a");
1030 	  else
1031 	    {
1032 	      names.push_back(prefix + ".so");
1033 	      names.push_back(prefix + ".a");
1034 	    }
1035 	}
1036       else
1037 	names.push_back(input_argument->name());
1038 
1039       for (std::vector<std::string>::const_iterator n = names.begin();
1040 	   n != names.end();
1041 	   ++n)
1042 	if (Input_file::try_extra_search_path(pindex, input_argument, *n,
1043 					      found_name, namep))
1044 	  return true;
1045 
1046       // It is not in the extra_search_path.
1047       name = dirpath.find(names, is_in_sysroot, pindex, found_name);
1048       if (name.empty())
1049 	{
1050 	  gold_error(_("cannot find %s%s"),
1051 		     input_argument->is_lib() ? "-l" : "",
1052 		     input_argument->name());
1053 	  return false;
1054 	}
1055       *namep = name;
1056       return true;
1057     }
1058   // Case 4: extra_search_path is not empty
1059   else
1060     {
1061       gold_assert(input_argument->extra_search_path() != NULL);
1062 
1063       if (try_extra_search_path(pindex, input_argument, input_argument->name(),
1064 				found_name, namep))
1065 	return true;
1066 
1067       // extra_search_path failed, so check the normal search-path.
1068       int index = *pindex;
1069       if (index > 0)
1070 	--index;
1071       name = dirpath.find(std::vector<std::string>(1, input_argument->name()),
1072 			  is_in_sysroot, &index, found_name);
1073       if (name.empty())
1074 	{
1075 	  gold_error(_("cannot find %s"),
1076 		     input_argument->name());
1077 	  return false;
1078 	}
1079       *namep = name;
1080       *pindex = index + 1;
1081       return true;
1082     }
1083 }
1084 
1085 // Open the file.
1086 
1087 bool
open(const Dirsearch & dirpath,const Task * task,int * pindex)1088 Input_file::open(const Dirsearch& dirpath, const Task* task, int* pindex)
1089 {
1090   std::string name;
1091   if (!Input_file::find_file(dirpath, pindex, this->input_argument_,
1092 			     &this->is_in_sysroot_, &this->found_name_, &name))
1093     return false;
1094 
1095   // Now that we've figured out where the file lives, try to open it.
1096 
1097   General_options::Object_format format =
1098     this->input_argument_->options().format_enum();
1099   bool ok;
1100   if (format == General_options::OBJECT_FORMAT_ELF)
1101     {
1102       ok = this->file_.open(task, name);
1103       this->format_ = FORMAT_ELF;
1104     }
1105   else
1106     {
1107       gold_assert(format == General_options::OBJECT_FORMAT_BINARY);
1108       ok = this->open_binary(task, name);
1109       this->format_ = FORMAT_BINARY;
1110     }
1111 
1112   if (!ok)
1113     {
1114       gold_error(_("cannot open %s: %s"),
1115 		 name.c_str(), strerror(errno));
1116       this->format_ = FORMAT_NONE;
1117       return false;
1118     }
1119 
1120   return true;
1121 }
1122 
1123 // Open a file for --format binary.
1124 
1125 bool
open_binary(const Task * task,const std::string & name)1126 Input_file::open_binary(const Task* task, const std::string& name)
1127 {
1128   // In order to open a binary file, we need machine code, size, and
1129   // endianness.  We may not have a valid target at this point, in
1130   // which case we use the default target.
1131   parameters_force_valid_target();
1132   const Target& target(parameters->target());
1133 
1134   Binary_to_elf binary_to_elf(target.machine_code(),
1135 			      target.get_size(),
1136 			      target.is_big_endian(),
1137 			      name);
1138   if (!binary_to_elf.convert(task))
1139     return false;
1140   return this->file_.open(task, name, binary_to_elf.converted_data_leak(),
1141 			  binary_to_elf.converted_size());
1142 }
1143 
1144 void
record_file_read(const std::string & name)1145 File_read::record_file_read(const std::string& name)
1146 {
1147   File_read::files_read.push_back(name);
1148 }
1149 
1150 void
write_dependency_file(const char * dependency_file_name,const char * output_file_name)1151 File_read::write_dependency_file(const char* dependency_file_name,
1152 				 const char* output_file_name)
1153 {
1154   FILE *depfile = fopen(dependency_file_name, "w");
1155 
1156   fprintf(depfile, "%s:", output_file_name);
1157   for (std::vector<std::string>::const_iterator it = files_read.begin();
1158        it != files_read.end();
1159        ++it)
1160     fprintf(depfile, " \\\n  %s", it->c_str());
1161   fprintf(depfile, "\n");
1162 
1163   for (std::vector<std::string>::const_iterator it = files_read.begin();
1164        it != files_read.end();
1165        ++it)
1166     fprintf(depfile, "\n%s:\n", it->c_str());
1167 
1168   fclose(depfile);
1169 }
1170 
1171 } // End namespace gold.
1172