--- /dev/null
+// descriptors.cc -- manage file descriptors for gold
+
+// Copyright 2008, 2009 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 <cstdio>
+#include <cstring>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "parameters.h"
+#include "options.h"
+#include "gold-threads.h"
+#include "descriptors.h"
+#include "binary-io.h"
+
+// Very old systems may not define FD_CLOEXEC.
+#ifndef FD_CLOEXEC
+#define FD_CLOEXEC 1
+#endif
+
+// O_CLOEXEC is only available on newer systems.
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#endif
+
+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), initialize_lock_(&this->lock_), 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.
+ bool lock_initialized = this->initialize_lock_.initialize();
+
+ gold_assert(lock_initialized || 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;
+ if (descriptor == this->stack_top_)
+ {
+ this->stack_top_ = pod->stack_next;
+ pod->stack_next = -1;
+ pod->is_on_stack = false;
+ }
+ return descriptor;
+ }
+ }
+
+ while (true)
+ {
+ // We always want to set the close-on-exec flag; we don't
+ // require callers to pass it.
+ flags |= O_CLOEXEC;
+
+ // Always open the file as a binary file.
+ flags |= O_BINARY;
+
+ 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)
+ {
+ // If we have any plugins, we really do need to set the
+ // close-on-exec flag, even if O_CLOEXEC is not defined.
+ // FIXME: In some cases O_CLOEXEC may be defined in the
+ // header file but not supported by the kernel.
+ // Unfortunately there doesn't seem to be any obvious way to
+ // detect that, as unknown flags passed to open are ignored.
+ if (O_CLOEXEC == 0
+ && parameters->options_valid()
+ && parameters->options().has_plugins())
+ fcntl(new_descriptor, F_SETFD, FD_CLOEXEC);
+
+ {
+ 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;
+ pod->is_on_stack = false;
+
+ ++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->is_on_stack)
+ {
+ pod->stack_next = this->stack_top_;
+ this->stack_top_ = descriptor;
+ pod->is_on_stack = true;
+ }
+ }
+}
+
+// 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;
+ pod->stack_next = -1;
+ pod->is_on_stack = false;
+ 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.
projects / msp430-binutils.git / blobdiff