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

168 lines
3.5 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>
/* libc plugin interface */
#include <libc-plugin/fd_alloc.h>
/* libc includes */
#include <fcntl.h>
#include <unistd.h>
/* libc-internal includes */
#include <libc_init.h>
#include <base/internal/unmanaged_singleton.h>
using namespace Libc;
using namespace Genode;
static Allocator *_alloc_ptr;
void Libc::init_fd_alloc(Allocator &alloc) { _alloc_ptr = &alloc; }
File_descriptor_allocator *Libc::file_descriptor_allocator()
{
if (_alloc_ptr)
return unmanaged_singleton<File_descriptor_allocator>(*_alloc_ptr);
error("missing call of 'init_fd_alloc'");
return nullptr;
}
File_descriptor_allocator::File_descriptor_allocator(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);
if (fdo->fd_path)
_alloc.free((void *)fdo->fd_path, ::strlen(fdo->fd_path) + 1);
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;
}
void File_descriptor_allocator::generate_info(Xml_generator &xml)
{
Lock::Guard guard(_lock);
_id_space.for_each<File_descriptor>([&] (File_descriptor &fd) {
xml.node("fd", [&] () {
xml.attribute("id", fd.libc_fd);
if (fd.fd_path)
xml.attribute("path", fd.fd_path);
if (fd.cloexec)
xml.attribute("cloexec", "yes");
if (((fd.flags & O_ACCMODE) != O_WRONLY))
xml.attribute("readable", "yes");
if (((fd.flags & O_ACCMODE) != O_RDONLY))
xml.attribute("writeable", "yes");
if (fd.plugin) {
::off_t const seek = fd.plugin->lseek(&fd, 0, SEEK_CUR);
if (seek)
xml.attribute("seek", seek);
}
});
});
}
void File_descriptor::path(char const *newpath)
{
if (fd_path)
warning("may leak former FD path memory");
if (!_alloc_ptr) {
error("missing call of 'init_fd_alloc'");
return;
}
if (newpath) {
Genode::size_t const path_size = ::strlen(newpath) + 1;
char *buf = (char*)_alloc_ptr->alloc(path_size);
if (!buf) {
error("could not allocate path buffer for libc_fd ", libc_fd);
return;
}
::memcpy(buf, newpath, path_size);
fd_path = buf;
} else
fd_path = 0;
}
/********************
** Libc functions **
********************/
extern "C" int __attribute__((weak)) getdtablesize(void) { return MAX_NUM_FDS; }