genode/repos/os/include/ram_fs/directory.h
2016-04-25 10:47:54 +02:00

231 lines
5.0 KiB
C++

/*
* \brief File-system directory node
* \author Norman Feske
* \date 2012-04-11
*/
/*
* Copyright (C) 2011-2015 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.
*/
#ifndef _INCLUDE__RAM_FS__DIRECTORY_H_
#define _INCLUDE__RAM_FS__DIRECTORY_H_
/* Genode includes */
#include <file_system/util.h>
/* local includes */
#include <ram_fs/node.h>
#include <ram_fs/file.h>
#include <ram_fs/symlink.h>
namespace File_system { class Directory; }
class File_system::Directory : public Node
{
private:
List<Node> _entries;
size_t _num_entries;
public:
Directory(char const *name) : _num_entries(0) { Node::name(name); }
Node *entry_unsynchronized(size_t index)
{
Node *node = _entries.first();
for (unsigned i = 0; i < index && node; node = node->next(), i++);
return node;
}
bool has_sub_node_unsynchronized(char const *name) const
{
Node const *sub_node = _entries.first();
for (; sub_node; sub_node = sub_node->next())
if (strcmp(sub_node->name(), name) == 0)
return true;
return false;
}
void adopt_unsynchronized(Node *node)
{
/*
* XXX inc ref counter
*/
_entries.insert(node);
_num_entries++;
mark_as_updated();
}
void discard_unsynchronized(Node *node)
{
_entries.remove(node);
_num_entries--;
mark_as_updated();
}
Node *lookup_and_lock(char const *path, bool return_parent = false)
{
if (strcmp(path, "") == 0) {
lock();
return this;
}
if (!path || path[0] == '/')
throw Lookup_failed();
/* find first path delimiter */
unsigned i = 0;
for (; path[i] && path[i] != '/'; i++);
/*
* If no path delimiter was found, we are the parent of the
* specified path.
*/
if (path[i] == 0 && return_parent) {
lock();
return this;
}
/*
* The offset 'i' corresponds to the end of the first path
* element, which can be either the end of the string or the
* first '/' character.
*/
/* try to find entry that matches the first path element */
Node *sub_node = _entries.first();
for (; sub_node; sub_node = sub_node->next())
if ((strlen(sub_node->name()) == i) &&
(strcmp(sub_node->name(), path, i) == 0))
break;
if (!sub_node)
throw Lookup_failed();
if (is_basename(path)) {
/*
* Because 'path' is a basename that corresponds to an
* existing sub_node, we have found what we were looking
* for.
*/
sub_node->lock();
return sub_node;
}
/*
* As 'path' contains one or more path delimiters, traverse
* into the sub directory names after the first path element.
*/
/*
* We cannot traverse into anything other than a directory.
*
* XXX we might follow symlinks here
*/
Directory *sub_dir = dynamic_cast<Directory *>(sub_node);
if (!sub_dir)
throw Lookup_failed();
return sub_dir->lookup_and_lock(path + i + 1, return_parent);
}
Directory *lookup_and_lock_dir(char const *path)
{
Node *node = lookup_and_lock(path);
Directory *dir = dynamic_cast<Directory *>(node);
if (dir)
return dir;
node->unlock();
throw Lookup_failed();
}
File *lookup_and_lock_file(char const *path)
{
Node *node = lookup_and_lock(path);
File *file = dynamic_cast<File *>(node);
if (file)
return file;
node->unlock();
throw Lookup_failed();
}
Symlink *lookup_and_lock_symlink(char const *path)
{
Node *node = lookup_and_lock(path);
Symlink *symlink = dynamic_cast<Symlink *>(node);
if (symlink)
return symlink;
node->unlock();
throw Lookup_failed();
}
/**
* Lookup parent directory of the specified path
*
* \throw Lookup_failed
*/
Directory *lookup_and_lock_parent(char const *path)
{
return static_cast<Directory *>(lookup_and_lock(path, true));
}
size_t read(char *dst, size_t len, seek_off_t seek_offset)
{
if (len < sizeof(Directory_entry)) {
PERR("read buffer too small for directory entry");
return 0;
}
seek_off_t index = seek_offset / sizeof(Directory_entry);
if (seek_offset % sizeof(Directory_entry)) {
PERR("seek offset not alighed to sizeof(Directory_entry)");
return 0;
}
Node *node = entry_unsynchronized(index);
/* index out of range */
if (!node)
return 0;
Directory_entry *e = (Directory_entry *)(dst);
e->inode = node->inode();
if (dynamic_cast<File *>(node)) e->type = Directory_entry::TYPE_FILE;
if (dynamic_cast<Directory *>(node)) e->type = Directory_entry::TYPE_DIRECTORY;
if (dynamic_cast<Symlink *>(node)) e->type = Directory_entry::TYPE_SYMLINK;
strncpy(e->name, node->name(), sizeof(e->name));
return sizeof(Directory_entry);
}
size_t write(char const *src, size_t len, seek_off_t seek_offset)
{
/* writing to directory nodes is not supported */
return 0;
}
size_t num_entries() const { return _num_entries; }
};
#endif /* _INCLUDE__RAM_FS__DIRECTORY_H_ */