// descriptors.cc -- manage file descriptors for gold
-// Copyright 2008 Free Software Foundation, Inc.
+// Copyright 2008, 2009 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
#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
{
// adjusted downward if we run out of file descriptors.
Descriptors::Descriptors()
- : lock_(NULL), open_descriptors_(), stack_top_(-1), current_(0),
- limit_(8192 - 16)
+ : lock_(NULL), initialize_lock_(&this->lock_), open_descriptors_(),
+ stack_top_(-1), current_(0), limit_(8192 - 16)
{
this->open_descriptors_.reserve(128);
}
// 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);
- }
+ bool lock_initialized = this->initialize_lock_.initialize();
+
+ gold_assert(lock_initialized || descriptor < 0);
if (descriptor >= 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
{
Hold_lock hl(*this->lock_);
- gold_error(_("file %s was removed during the link"),
- this->open_descriptors_[descriptor].name);
+ gold_error(_("file %s was removed during the link"), name);
}
errno = ENOENT;
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;
+ // 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;
- if (!pod->is_claimed)
++this->current_;
- pod->is_claimed = false;
- if (this->current_ >= this->limit_)
- this->close_some_descriptor();
+ if (this->current_ >= this->limit_)
+ this->close_some_descriptor();
- return new_descriptor;
+ return new_descriptor;
+ }
}
// We ran out of file descriptors.
else
{
pod->inuse = false;
- if (!pod->is_write)
+ if (!pod->is_write && !pod->is_on_stack)
{
pod->stack_next = this->stack_top_;
this->stack_top_ = descriptor;
+ pod->is_on_stack = true;
}
}
}
-// Claim the file descriptor DESCRIPTOR for a plugin. This effectively
-// removes the descriptor from the pool of linker-managed descriptors,
-// as the plugin will assume responsibility for closing it.
-// The IS_CLAIMED flag allows us to recognize when a file descriptor
-// has been reused after being closed by the plugin.
-
-void
-Descriptors::claim_for_plugin(int descriptor)
-{
- Hold_lock hl(*this->lock_);
-
- gold_assert(descriptor >= 0
- && (static_cast<size_t>(descriptor)
- < this->open_descriptors_.size()));
- Open_descriptor* pod = &this->open_descriptors_[descriptor];
- pod->is_claimed = 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
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;