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133 lines
2.7 KiB
C++
133 lines
2.7 KiB
C++
/*
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* \brief file descriptor allocator interface
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* \author Christian Prochaska
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* \date 2010-01-21
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*
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*/
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/*
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* Copyright (C) 2010-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _LIBC_PLUGIN__FD_ALLOC_H_
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#define _LIBC_PLUGIN__FD_ALLOC_H_
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/* Genode includes */
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#include <base/mutex.h>
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#include <base/log.h>
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#include <os/path.h>
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#include <base/allocator.h>
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#include <base/id_space.h>
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#include <util/bit_allocator.h>
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#include <util/xml_generator.h>
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/* libc includes */
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#include <stdlib.h>
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#include <string.h>
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#include <libc-plugin/plugin.h>
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enum { MAX_NUM_FDS = 1024 };
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namespace Libc {
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/**
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* Plugin-specific file-descriptor context
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*/
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struct Plugin_context { virtual ~Plugin_context() { } };
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enum { ANY_FD = -1 };
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struct File_descriptor
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{
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Genode::Mutex mutex { };
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typedef Genode::Id_space<File_descriptor> Id_space;
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Id_space::Element _elem;
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int const libc_fd = _elem.id().value;
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char const *fd_path = nullptr; /* for 'fchdir', 'fstat' */
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Plugin *plugin;
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Plugin_context *context;
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int flags = 0; /* for 'fcntl' */
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bool cloexec = 0; /* for 'fcntl' */
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bool modified = false;
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File_descriptor(Id_space &id_space, Plugin &plugin, Plugin_context &context,
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Id_space::Id id)
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: _elem(*this, id_space, id), plugin(&plugin), context(&context) { }
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void path(char const *newpath);
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};
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class File_descriptor_allocator
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{
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private:
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Genode::Mutex _mutex;
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Genode::Allocator &_alloc;
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typedef File_descriptor::Id_space Id_space;
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Id_space _id_space;
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Genode::Bit_allocator<MAX_NUM_FDS> _id_allocator;
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public:
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/**
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* Constructor
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*/
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File_descriptor_allocator(Genode::Allocator &_alloc);
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/**
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* Allocate file descriptor
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*/
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File_descriptor *alloc(Plugin *plugin, Plugin_context *context, int libc_fd = -1);
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/**
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* Release file descriptor
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*/
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void free(File_descriptor *fdo);
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/**
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* Prevent the use of the specified file descriptor
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*/
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void preserve(int libc_fd);
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File_descriptor *find_by_libc_fd(int libc_fd);
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/**
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* Return any file descriptor with close-on-execve flag set
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*
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* \return pointer to file descriptor, or
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* nullptr is no such file descriptor exists
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*/
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File_descriptor *any_cloexec_libc_fd();
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/**
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* Return file-descriptor ID of any open file, or -1 if no file is
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* open
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*/
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int any_open_fd();
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void generate_info(Genode::Xml_generator &);
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};
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/**
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* Return singleton instance of file-descriptor allocator
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*/
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extern File_descriptor_allocator *file_descriptor_allocator();
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}
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#endif /* _LIBC_PLUGIN__FD_ALLOC_H_ */
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