genode/repos/libports/src/lib/libc/fd_alloc.cc

104 lines
2.3 KiB
C++

/*
* \brief File-descriptor allocator implementation
* \author Christian Prochaska
* \author Norman Feske
* \date 2010-01-21
*/
/*
* Copyright (C) 2010-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
/* Genode includes */
#include <util/construct_at.h>
#include <base/env.h>
#include <base/log.h>
#include <libc/allocator.h>
/* libc plugin interface */
#include <libc-plugin/fd_alloc.h>
using namespace Libc;
using namespace Genode;
File_descriptor_allocator *Libc::file_descriptor_allocator()
{
static bool constructed = false;
static char placeholder[sizeof(File_descriptor_allocator)];
static Libc::Allocator md_alloc;
if (!constructed) {
Genode::construct_at<File_descriptor_allocator>(placeholder, md_alloc);
constructed = true;
}
return reinterpret_cast<File_descriptor_allocator *>(placeholder);
}
File_descriptor_allocator::File_descriptor_allocator(Genode::Allocator &alloc)
: _alloc(alloc)
{ }
File_descriptor *File_descriptor_allocator::alloc(Plugin *plugin,
Plugin_context *context,
int libc_fd)
{
Lock::Guard guard(_lock);
bool const any_fd = (libc_fd < 0);
if (any_fd)
return new (_alloc) File_descriptor(_id_space, *plugin, *context);
Id_space::Id const id {(unsigned)libc_fd};
return new (_alloc) File_descriptor(_id_space, *plugin, *context, id);
}
void File_descriptor_allocator::free(File_descriptor *fdo)
{
Lock::Guard guard(_lock);
::free((void *)fdo->fd_path);
Genode::destroy(_alloc, fdo);
}
void File_descriptor_allocator::preserve(int fd)
{
if (!find_by_libc_fd(fd))
alloc(nullptr, nullptr, fd);
}
File_descriptor *File_descriptor_allocator::find_by_libc_fd(int libc_fd)
{
Lock::Guard guard(_lock);
if (libc_fd < 0)
return nullptr;
File_descriptor *result = nullptr;
try {
Id_space::Id const id {(unsigned)libc_fd};
_id_space.apply<File_descriptor>(id, [&] (File_descriptor &fd) {
result = &fd; });
} catch (Id_space::Unknown_id) { }
return result;
}
/********************
** Libc functions **
********************/
extern "C" int __attribute__((weak)) getdtablesize(void) { return MAX_NUM_FDS; }