PR 5990

	* descriptors.cc: New file.
	* descriptors.h: New file.
	* gold-threads.h (class Hold_optional_lock): New class.
	* fileread.cc: Include "descriptors.h".
	(File_read::~File_read): Release descriptor rather than closing
	it.
	(File_read::open) [file]: Call open_descriptor rather than open.
	Set is_descriptor_opened_.
	(File_read::open) [memory]: Assert that descriptor is not open.
	(File_read::reopen_descriptor): New function.
	(File_read::release): Release descriptor.
	(File_read::do_read): Make non-const.  Reopen descriptor.
	(File_read::read): Make non-const.
	(File_read::make_view): Reopen descriptor.
	(File_read::do_readv): Likewise.
	* fileread.h (class File_read): Add is_descriptor_opened_ field.
	Update declarations.
	* layout.cc: Include "descriptors.h".
	(Layout::create_build_id): Use open_descriptor rather than open.
	* output.cc: Include "descriptors.h".
	(Output_file::open): Use open_descriptor rather than open.
	* archive.cc (Archive::const_iterator): Change Archive to be
	non-const.
	(Archive::begin, Archive::end): Make non-const.
	(Archive::count_members): Likewise.
	* archive.h (class Archive): Update declarations.
	* object.h (Object::read): Make non-const.
	* Makefile.am (CCFILES): Add descriptors.cc.
	(HFILES): Add descriptors.h.
	* Makefile.in: Rebuild.

1 files changed, 211 insertions, 0 deletions

diff --git a/gold/descriptors.cc b/gold/descriptors.cc
new file mode 100644
index 0000000..75a7a86
--- /dev/null
+++ b/gold/descriptors.cc
@@ -0,0 +1,211 @@
+// descriptors.cc -- manage file descriptors for gold
+
+// Copyright 2008 Free Software Foundation, Inc.
+// Written by Ian Lance Taylor <iant@google.com>.
+
+// This file is part of gold.
+
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+// MA 02110-1301, USA.
+
+#include "gold.h"
+
+#include <cerrno>
+#include <cstring>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "parameters.h"
+#include "gold-threads.h"
+#include "descriptors.h"
+
+namespace gold
+{
+
+// Class Descriptors.
+
+// The default for limit_ is meant to simply be large.  It gets
+// adjusted downward if we run out of file descriptors.
+
+Descriptors::Descriptors()
+  : lock_(NULL), open_descriptors_(), stack_top_(-1), current_(0),
+    limit_(8192 - 16)
+{
+  this->open_descriptors_.reserve(128);
+}
+
+// Open a file.
+
+int
+Descriptors::open(int descriptor, const char* name, int flags, int mode)
+{
+  // We don't initialize this until we are called, because we can't
+  // initialize a Lock until we have parsed the options to find out
+  // whether we are running with threads.  We can be called before
+  // options are valid when reading a linker script.
+  if (this->lock_ == NULL)
+    {
+      if (parameters->options_valid())
+	this->lock_ = new Lock();
+      else
+	gold_assert(descriptor < 0);
+    }
+
+  if (descriptor >= 0)
+    {
+      Hold_lock hl(*this->lock_);
+
+      gold_assert(static_cast<size_t>(descriptor)
+		  < this->open_descriptors_.size());
+      Open_descriptor* pod = &this->open_descriptors_[descriptor];
+      if (pod->name == name
+	  || (pod->name != NULL && strcmp(pod->name, name) == 0))
+	{
+	  gold_assert(!pod->inuse);
+	  pod->inuse = true;
+	  return descriptor;
+	}
+    }
+
+  while (true)
+    {
+      int new_descriptor = ::open(name, flags, mode);
+      if (new_descriptor < 0
+	  && errno != ENFILE
+	  && errno != EMFILE)
+	{
+	  if (descriptor >= 0 && errno == ENOENT)
+	    {
+	      {
+		Hold_lock hl(*this->lock_);
+
+		gold_error(_("file %s was removed during the link"),
+			   this->open_descriptors_[descriptor].name);
+	      }
+
+	      errno = ENOENT;
+	    }
+
+	  return new_descriptor;
+	}
+
+      if (new_descriptor >= 0)
+	{
+	  Hold_optional_lock hl(this->lock_);
+
+	  if (static_cast<size_t>(new_descriptor)
+	      >= this->open_descriptors_.size())
+	    this->open_descriptors_.resize(new_descriptor + 64);
+
+	  Open_descriptor* pod = &this->open_descriptors_[new_descriptor];
+	  pod->name = name;
+	  pod->stack_next = -1;
+	  pod->inuse = true;
+	  pod->is_write = (flags & O_ACCMODE) != O_RDONLY;
+
+	  ++this->current_;
+	  if (this->current_ >= this->limit_)
+	    this->close_some_descriptor();
+
+	  return new_descriptor;
+	}
+
+      // We ran out of file descriptors.
+      {
+	Hold_optional_lock hl(this->lock_);
+
+	this->limit_ = this->current_ - 16;
+	if (this->limit_ < 8)
+	  this->limit_ = 8;
+	if (!this->close_some_descriptor())
+	  gold_fatal(_("out of file descriptors and couldn't close any"));
+      }
+    }
+}
+
+// Release a descriptor.
+
+void
+Descriptors::release(int descriptor, bool permanent)
+{
+  Hold_optional_lock hl(this->lock_);
+
+  gold_assert(descriptor >= 0
+	      && (static_cast<size_t>(descriptor)
+		  < this->open_descriptors_.size()));
+  Open_descriptor* pod = &this->open_descriptors_[descriptor];
+
+  if (permanent
+      || (this->current_ > this->limit_ && !pod->is_write))
+    {
+      if (::close(descriptor) < 0)
+	gold_warning(_("while closing %s: %s"), pod->name, strerror(errno));
+      pod->name = NULL;
+      --this->current_;
+    }
+  else
+    {
+      pod->inuse = false;
+      if (!pod->is_write)
+	{
+	  pod->stack_next = this->stack_top_;
+	  this->stack_top_ = descriptor;
+	}
+    }
+}
+
+// Close some descriptor.  The lock is held when this is called.  We
+// close the descriptor on the top of the free stack.  Note that this
+// is the opposite of an LRU algorithm--we close the most recently
+// used descriptor.  That is because the linker tends to cycle through
+// all the files; after we release a file, we are unlikely to need it
+// again until we have looked at all the other files.  Return true if
+// we closed a descriptor.
+
+bool
+Descriptors::close_some_descriptor()
+{
+  int last = -1;
+  int i = this->stack_top_;
+  while (i >= 0)
+    {
+      gold_assert(static_cast<size_t>(i) < this->open_descriptors_.size());
+      Open_descriptor* pod = &this->open_descriptors_[i];
+      if (!pod->inuse && !pod->is_write)
+	{
+	  if (::close(i) < 0)
+	    gold_warning(_("while closing %s: %s"), pod->name, strerror(errno));
+	  --this->current_;
+	  pod->name = NULL;
+	  if (last < 0)
+	    this->stack_top_ = pod->stack_next;
+	  else
+	    this->open_descriptors_[last].stack_next = pod->stack_next;
+	  return true;
+	}
+      last = i;
+      i = pod->stack_next;
+    }
+
+  // We couldn't find any descriptors to close.  This is weird but not
+  // necessarily an error.
+  return false;
+}
+
+// The single global variable which manages descriptors.
+
+Descriptors descriptors;
+
+} // End namespace gold.