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[/] [openrisc/] [trunk/] [gnu-src/] [binutils-2.20.1/] [gold/] [descriptors.cc] - Rev 243
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// 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.
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