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36f91c2007
This lock is needed to prevent multiple threads and/or multiple
libc-plugins from using the same file descriptor in p{read,write}.
Fixes #948.
95 lines
1.8 KiB
C++
95 lines
1.8 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) 2010-2013 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 General Public License version 2.
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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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#include <base/allocator_avl.h>
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#include <base/lock.h>
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#include <base/printf.h>
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#include <os/path.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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class 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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int libc_fd;
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char *fd_path; /* for 'fchdir()' */
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Plugin *plugin;
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Plugin_context *context;
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Genode::Lock lock;
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void path(char const *newpath)
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{
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if (newpath) {
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size_t path_size = ::strlen(newpath) + 1;
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fd_path = (char*)malloc(path_size);
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if (!fd_path) {
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PERR("could not allocate path buffer for libc_fd %d%s",
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libc_fd, libc_fd == ANY_FD ? " (any)" : "");
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return;
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}
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::memcpy(fd_path, newpath, path_size);
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} else
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fd_path = 0;
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}
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};
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class File_descriptor_allocator : Allocator_avl_tpl<File_descriptor>
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{
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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();
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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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File_descriptor *find_by_libc_fd(int libc_fd);
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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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