367 lines
8.5 KiB
C++
367 lines
8.5 KiB
C++
/*
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* \brief Embedded RAM VFS
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* \author Emery Hemingway
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* \date 2015-07-21
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*/
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/*
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* Copyright (C) 2015 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 _INCLUDE__VFS__RAM_FILE_SYSTEM_H_
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#define _INCLUDE__VFS__RAM_FILE_SYSTEM_H_
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#include <vfs/dir_file_system.h>
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#include <ram_fs/directory.h>
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namespace Vfs {
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using namespace ::File_system;
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class Ram_file_system;
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}
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class Vfs::Ram_file_system : public File_system, private ::File_system::Directory
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{
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private:
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struct Ram_vfs_handle : Vfs_handle
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{
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private:
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::File_system::Node *_node;
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public:
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Ram_vfs_handle(File_system &fs, int status_flags,
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::File_system::Node *node)
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: Vfs_handle(fs, fs, status_flags), _node(node)
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{ }
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::File_system::Node *node() const { return _node; }
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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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Ram_file_system(Xml_node config)
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: Directory("/") { }
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/***************************
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** File_system interface **
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***************************/
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static char const *name() { return "ram"; }
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/********************************
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** File I/O service interface **
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********************************/
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Write_result write(Vfs_handle *vfs_handle,
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char const *buf, file_size buf_size,
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file_size &out_count)
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{
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Ram_vfs_handle const *handle = static_cast<Ram_vfs_handle *>(vfs_handle);
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out_count = handle->node()->write(buf, buf_size, handle->seek());
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return WRITE_OK;
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}
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Read_result read(Vfs_handle *vfs_handle, char *dst, file_size count,
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file_size &out_count)
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{
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Ram_vfs_handle const *handle = static_cast<Ram_vfs_handle *>(vfs_handle);
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out_count = handle->node()->read(dst, count, handle->seek());
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return READ_OK;
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}
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Ftruncate_result ftruncate(Vfs_handle *vfs_handle, file_size len)
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{
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Ram_vfs_handle const *handle = static_cast<Ram_vfs_handle *>(vfs_handle);
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File *file = dynamic_cast<File *>(handle->node());
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if (!file)
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return FTRUNCATE_ERR_INTERRUPT;
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file->truncate(len);
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return FTRUNCATE_OK;
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}
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void register_read_ready_sigh(Vfs_handle *vfs_handle,
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Signal_context_capability sigh)
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{ }
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/*********************************
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** Directory service interface **
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*********************************/
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Dataspace_capability dataspace(char const *path)
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{
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Ram_dataspace_capability ds_cap;
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char *local_addr = 0;
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try {
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File *file = lookup_and_lock_file(path);
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Node_lock_guard guard(file);
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ds_cap = env()->ram_session()->alloc(file->length());
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local_addr = env()->rm_session()->attach(ds_cap);
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file->read(local_addr, file->length(), 0);
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env()->rm_session()->detach(local_addr);
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} catch(...) {
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env()->rm_session()->detach(local_addr);
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env()->ram_session()->free(ds_cap);
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return Dataspace_capability();
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}
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return ds_cap;
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}
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void release(char const *path, Dataspace_capability ds_cap)
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{
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env()->ram_session()->free(static_cap_cast<Genode::Ram_dataspace>(ds_cap));
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}
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Open_result open(char const *path, unsigned mode, Vfs_handle **handle)
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{
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bool const create = mode & OPEN_MODE_CREATE;
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char const *name = basename(++path);
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Node *node;
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try {
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if (create) {
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Directory *parent = lookup_and_lock_parent(path);
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Node_lock_guard parent_guard(parent);
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if (parent->has_sub_node_unsynchronized(name))
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return OPEN_ERR_EXISTS;
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node = new (env()->heap())
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File(*env()->heap(), name);
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parent->adopt_unsynchronized(node);
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} else {
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node = lookup_and_lock(path);
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node->unlock();
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}
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} catch (Lookup_failed) {
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return OPEN_ERR_UNACCESSIBLE;
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}
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*handle = new (env()->heap())
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Ram_vfs_handle(*this, mode, node);
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return OPEN_OK;
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}
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Stat_result stat(char const *path, Stat &stat)
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{
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try {
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Node *node = lookup_and_lock(++path);
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Node_lock_guard node_guard(node);
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memset(&stat, 0x00, sizeof(stat));
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stat.inode = node->inode();
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File *file = dynamic_cast<File *>(node);
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if (file) {
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stat.size = file->length();
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stat.mode = STAT_MODE_FILE | 0777;
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return STAT_OK;
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}
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Directory *dir = dynamic_cast<Directory *>(node);
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if (dir) {
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stat.size = dir->num_entries();
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stat.mode = STAT_MODE_DIRECTORY | 0777;
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return STAT_OK;
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}
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Symlink *symlink = dynamic_cast<Symlink *>(node);
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if (symlink) {
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stat.size = symlink->length();
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stat.mode = STAT_MODE_SYMLINK | 0777;
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return STAT_OK;
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}
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} catch (Lookup_failed) { }
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return STAT_ERR_NO_ENTRY;
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}
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Dirent_result dirent(char const *path, file_offset index, Dirent &dirent)
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{
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try {
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Directory *dir = lookup_and_lock_dir(++path);
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Node_lock_guard guard(dir);
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Node *node = dir->entry_unsynchronized(index);
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if (!node) {
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dirent.fileno = 0;
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dirent.type = DIRENT_TYPE_END;
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dirent.name[0] = '\0';
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return DIRENT_OK;
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}
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dirent.fileno = index+1;
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if (dynamic_cast<File *>(node))
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dirent.type = DIRENT_TYPE_FILE;
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else if (dynamic_cast<Directory *>(node))
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dirent.type = DIRENT_TYPE_DIRECTORY;
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else if (dynamic_cast<Symlink *>(node))
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dirent.type = DIRENT_TYPE_SYMLINK;
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strncpy(dirent.name, node->name(), sizeof(dirent.name));
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} catch (Lookup_failed) {
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return DIRENT_ERR_INVALID_PATH;
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}
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return DIRENT_OK;
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}
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Unlink_result unlink(char const *path)
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{
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try {
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Directory *parent = lookup_and_lock_parent(++path);
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Node_lock_guard parent_guard(parent);
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char const *name = basename(path);
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Node *node = parent->lookup_and_lock(name);
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parent->discard_unsynchronized(node);
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destroy(env()->heap(), node);
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} catch (Lookup_failed) {
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return UNLINK_ERR_NO_ENTRY;
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}
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return UNLINK_OK;
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}
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Readlink_result readlink(char const *path, char *buf,
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file_size buf_size, file_size &out_len)
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{
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try {
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Symlink *symlink = lookup_and_lock_symlink(++path);
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Node_lock_guard guard(symlink);
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out_len = symlink->read(buf, buf_size, 0);
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} catch (Lookup_failed) {
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return READLINK_ERR_NO_ENTRY;
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}
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return READLINK_OK;
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}
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Rename_result rename(char const *from, char const *to)
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{
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try {
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Directory *from_dir = lookup_and_lock_parent(++from);
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Node_lock_guard from_guard(from_dir);
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Directory *to_dir = lookup_and_lock_parent(++to);
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Node_lock_guard to_guard(to_dir);
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Node *node = from_dir->lookup_and_lock(basename(from));
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Node_lock_guard guard(node);
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from_dir->discard_unsynchronized(node);
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node->name(basename(to));
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to_dir->adopt_unsynchronized(node);
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} catch (Lookup_failed) {
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return RENAME_ERR_NO_ENTRY;
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}
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return RENAME_OK;
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}
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Mkdir_result mkdir(char const *path, unsigned mode)
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{
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try {
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Directory *parent = lookup_and_lock_parent(++path);
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Node_lock_guard parent_guard(parent);
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char const *name = basename(path);
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if (strlen(name) > MAX_NAME_LEN)
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return MKDIR_ERR_NAME_TOO_LONG;
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if (parent->has_sub_node_unsynchronized(name))
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return MKDIR_ERR_EXISTS;
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parent->adopt_unsynchronized(new (env()->heap())
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Directory(name));
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} catch (Lookup_failed) {
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return MKDIR_ERR_NO_ENTRY;
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} catch (Allocator::Out_of_memory) {
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return MKDIR_ERR_NO_SPACE;
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}
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return MKDIR_OK;
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}
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Symlink_result symlink(char const *from, char const *to)
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{
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try {
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Directory *parent = lookup_and_lock_parent(++to);
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Node_lock_guard parent_guard(parent);
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char const *name = basename(to);
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if (strlen(name) > MAX_NAME_LEN)
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return SYMLINK_ERR_NAME_TOO_LONG;
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if (parent->has_sub_node_unsynchronized(name))
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return SYMLINK_ERR_EXISTS;
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Symlink * const symlink = new (env()->heap())
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Symlink(name);
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parent->adopt_unsynchronized(symlink);
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symlink->write(from, strlen(from), 0);
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} catch (Lookup_failed) {
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return SYMLINK_ERR_NO_ENTRY;
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} catch (Allocator::Out_of_memory) {
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return SYMLINK_ERR_NO_SPACE;
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}
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return SYMLINK_OK;
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}
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file_size num_dirent(char const *path)
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{
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try {
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Directory *dir = lookup_and_lock_dir(++path);
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Node_lock_guard guard(dir);
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return dir->num_entries();
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} catch (Lookup_failed) {
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return 0;
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}
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}
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bool is_directory(char const *path)
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{
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try {
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lookup_and_lock_dir(++path)->unlock();
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return true;
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} catch (...) {
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return false;
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}
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}
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char const *leaf_path(char const *path)
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{
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try {
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lookup_and_lock(path+1)->unlock();
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return path;
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} catch (...) { }
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return 0;
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}
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};
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#endif /* _INCLUDE__VFS__RAM_FILE_SYSTEM_H_ */
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