/*
* Copyright (c) 2007 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup fs
* @{
*/
/**
* @file vfs_open.c
* @brief VFS_OPEN method.
*/
#include <ipc/ipc.h>
#include <async.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <bool.h>
#include <futex.h>
#include <libadt/list.h>
#include <sys/types.h>
#include "vfs.h"
/** Per-connection futex protecting the files array. */
__thread atomic_t files_futex = FUTEX_INITIALIZER;
/**
* This is a per-connection table of open files.
* Our assumption is that each client opens only one connection and therefore
* there is one table of open files per task. However, this may not be the case
* and the client can open more connections to VFS. In that case, there will be
* several tables and several file handle name spaces per task. Besides of this,
* the functionality will stay unchanged. So unless the client knows what it is
* doing, it should open one connection to VFS only.
*
* Allocation of the open files table is deferred until the client makes the
* first VFS_OPEN operation.
*/
__thread vfs_file_t *files = NULL;
/** Initialize the table of open files. */
static bool vfs_conn_open_files_init(void)
{
/*
* Optimized fast path that will never go to sleep unnecessarily.
* The assumption is that once files is non-zero, it will never be zero
* again.
*/
if (files)
return true;
futex_down(&files_futex);
if (!files) {
files
= malloc(MAX_OPEN_FILES
* sizeof(vfs_file_t
));
if (!files) {
futex_up(&files_futex);
return false;
}
memset(files
, 0, MAX_OPEN_FILES
* sizeof(vfs_file_t
));
}
futex_up(&files_futex);
return true;
}
void vfs_open(ipc_callid_t rid, ipc_call_t *request)
{
if (!vfs_conn_open_files_init()) {
ipc_answer_fast_0(rid, ENOMEM);
return;
}
/*
* The POSIX interface is open(path, flags, mode).
* We can receive flags and mode along with the VFS_OPEN call; the path
* will need to arrive in another call.
*/
int flags = IPC_GET_ARG1(*request);
int mode = IPC_GET_ARG2(*request);
size_t size;
ipc_callid_t callid;
ipc_call_t call;
if (!ipc_data_receive(&callid, &call, NULL, &size)) {
ipc_answer_fast_0(callid, EINVAL);
ipc_answer_fast_0(rid, EINVAL);
return;
}
/*
* Now we are on the verge of accepting the path.
*
* There is one optimization we could do in the future: copy the path
* directly into the PLB using some kind of a callback.
*/
if (!path) {
ipc_answer_fast_0(callid, ENOMEM);
ipc_answer_fast_0(rid, ENOMEM);
return;
}
int rc;
if (rc = ipc_data_deliver(callid, &call, path, size)) {
ipc_answer_fast_0(rid, rc);
return;
}
/*
* The path is now populated and we can call vfs_lookup_internal().
*/
vfs_triplet_t triplet;
rc = vfs_lookup_internal(path, size, &triplet, NULL);
if (rc) {
ipc_answer_fast_0(rid, rc);
return;
}
/*
* Path is no longer needed.
*/
vfs_node_t *node = vfs_node_get(&triplet);
// TODO: not finished
}
/**
* @}
*/