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

84 lines
2.0 KiB
C++

/*
* \brief File-descriptor allocator implementation
* \author Christian Prochaska
* \author Norman Feske
* \date 2010-01-21
*/
/*
* Copyright (C) 2010-2013 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
/* Genode includes */
#include <base/env.h>
#include <base/printf.h>
/* libc plugin interface */
#include <libc-plugin/fd_alloc.h>
namespace Libc {
File_descriptor_allocator *file_descriptor_allocator()
{
static File_descriptor_allocator _file_descriptor_allocator;
return &_file_descriptor_allocator;
}
}
using namespace Libc;
using namespace Genode;
File_descriptor_allocator::File_descriptor_allocator()
: Allocator_avl_tpl<File_descriptor>(Genode::env()->heap())
{
add_range(0, MAX_NUM_FDS);
}
File_descriptor *File_descriptor_allocator::alloc(Plugin *plugin,
Plugin_context *context,
int libc_fd)
{
/* we use addresses returned by the allocator as file descriptors */
addr_t addr = (libc_fd <= ANY_FD ? ANY_FD : libc_fd);
/* allocate fresh fd if the default value for 'libc_fd' was specified */
bool alloc_ok = false;
if (libc_fd <= ANY_FD)
alloc_ok = Allocator_avl_base::alloc(1, reinterpret_cast<void**>(&addr));
else
alloc_ok = (Allocator_avl_base::alloc_addr(1, addr).is_ok());
if (!alloc_ok) {
PERR("could not allocate libc_fd %d%s",
libc_fd, libc_fd == ANY_FD ? " (any)" : "");
return 0;
}
File_descriptor *fdo = metadata((void*)addr);
fdo->libc_fd = (int)addr;
fdo->fd_path = 0;
fdo->plugin = plugin;
fdo->context = context;
fdo->lock = Lock(Lock::UNLOCKED);
return fdo;
}
void File_descriptor_allocator::free(File_descriptor *fdo)
{
::free((void *)fdo->fd_path);
Allocator_avl_base::free(reinterpret_cast<void*>(fdo->libc_fd));
}
File_descriptor *File_descriptor_allocator::find_by_libc_fd(int libc_fd)
{
return metadata(reinterpret_cast<void*>(libc_fd));
}