/*
* 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.c
* @brief VFS multiplexer for HelenOS.
*/
#include <ipc/ipc.h>
#include <ipc/services.h>
#include <async.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <bool.h>
#include <futex.h>
#include <libadt/list.h>
#include "vfs.h"
atomic_t fs_head_futex = FUTEX_INITIALIZER;
link_t fs_head;
/** Verify the VFS info structure.
*
* @param info Info structure to be verified.
*
* @return Non-zero if the info structure is sane, zero otherwise.
*/
static bool vfs_info_sane(vfs_info_t *info)
{
int i;
/*
* Check if the name is non-empty and is composed solely of ASCII
* characters [a-z]+[a-z0-9_-]*.
*/
return false;
for (i = 1; i < FS_NAME_MAXLEN; i++) {
(info->name[i] != '-') && (info->name[i] != '_')) {
if (info->name[i] == '\0')
break;
else
return false;
}
}
/*
* Check if the FS implements mandatory VFS operations.
*/
if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_REGISTER)] != VFS_OP_DEFINED)
return false;
if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_MOUNT)] != VFS_OP_DEFINED)
return false;
if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_UNMOUNT)] != VFS_OP_DEFINED)
return false;
if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] != VFS_OP_DEFINED)
return false;
if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_OPEN)] != VFS_OP_DEFINED)
return false;
if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_CLOSE)] != VFS_OP_DEFINED)
return false;
if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_READ)] != VFS_OP_DEFINED)
return false;
/*
* Check if each operation is either not defined, defined or default.
*/
for (i = VFS_FIRST; i < VFS_LAST; i++) {
if ((IPC_METHOD_TO_VFS_OP(i) != VFS_OP_NULL) &&
(IPC_METHOD_TO_VFS_OP(i) != VFS_OP_DEFAULT) &&
(IPC_METHOD_TO_VFS_OP(i) != VFS_OP_DEFINED))
return false;
}
return true;
}
/** VFS_REGISTER protocol function.
*
* @param rid Hash of the call with the request.
* @param request Call structure with the request.
*/
static void vfs_register(ipc_callid_t rid, ipc_call_t *request)
{
ipc_callid_t callid;
ipc_call_t call;
int rc;
size_t size;
/*
* The first call has to be IPC_M_DATA_SEND in which we receive the
* VFS info structure from the client FS.
*/
if (!ipc_data_send_accept(&callid, &call, NULL, &size)) {
/*
* The client doesn't obey the same protocol as we do.
*/
ipc_answer_fast(callid, EINVAL, 0, 0);
ipc_answer_fast(rid, EINVAL, 0, 0);
return;
}
/*
* We know the size of the VFS info structure. See if the client
* understands this easy concept too.
*/
if (size != sizeof(vfs_info_t)) {
/*
* The client is sending us something, which cannot be
* the info structure.
*/
ipc_answer_fast(callid, EINVAL, 0, 0);
ipc_answer_fast(rid, EINVAL, 0, 0);
return;
}
fs_info_t *fs_info;
/*
* Allocate and initialize a buffer for the fs_info structure.
*/
fs_info
= (fs_info_t
*) malloc(sizeof(fs_info_t
)); if (!fs_info) {
ipc_answer_fast(callid, ENOMEM, 0, 0);
ipc_answer_fast(rid, ENOMEM, 0, 0);
return;
}
link_initialize(&fs_info->fs_link);
rc = ipc_data_send_answer(callid, &call, &fs_info->vfs_info, size);
if (!rc) {
ipc_answer_fast(callid, rc, 0, 0);
ipc_answer_fast(rid, rc, 0, 0);
return;
}
if (!vfs_info_sane(&fs_info->vfs_info)) {
ipc_answer_fast(callid, EINVAL, 0, 0);
ipc_answer_fast(rid, EINVAL, 0, 0);
return;
}
futex_down(&fs_head_futex);
/*
* Check for duplicit registrations.
*/
link_t *cur;
for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
fs_info_t *fi = list_get_instance(cur, fs_info_t,
fs_link);
/* TODO: replace strcmp with strncmp once we have it */
if (strcmp(fs_info
->vfs_info.
name, fi
->vfs_info.
name) == 0) { /*
* We already register a fs like this.
*/
futex_up(&fs_head_futex);
ipc_answer_fast(callid, EEXISTS, 0, 0);
ipc_answer_fast(rid, EEXISTS, 0, 0);
return;
}
}
/*
* Add fs_info to the list of registered FS's.
*/
list_append(&fs_info->fs_link, &fs_head);
/*
* ACK receiving a properly formatted, non-duplicit vfs_info.
*/
ipc_answer_fast(callid, EOK, 0, 0);
/*
* Now we want the client to send us the IPC_M_CONNECT_TO_ME call so
* that a callback connection is created and we have a phone through
* which to forward VFS requests to it.
*/
callid = async_get_call(&call);
if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) {
list_remove(&fs_info->fs_link);
futex_up(&fs_head_futex);
ipc_answer_fast(callid, EINVAL, 0, 0);
ipc_answer_fast(rid, EINVAL, 0, 0);
return;
}
fs_info->phone = IPC_GET_ARG3(call);
ipc_answer_fast(callid, EOK, 0, 0);
futex_up(&fs_head_futex);
/*
* That was it. The FS has been registered.
*/
ipc_answer_fast(rid, EOK, 0, 0);
}
static void vfs_connection(ipc_callid_t iid, ipc_call_t *icall)
{
bool keep_on_going = 1;
/*
* The connection was opened via the IPC_CONNECT_ME_TO call.
* This call needs to be answered.
*/
ipc_answer_fast(iid, EOK, 0, 0);
/*
* Here we enter the main connection fibril loop.
* The logic behind this loop and the protocol is that we'd like to keep
* each connection open for a while before we close it. The benefit of
* this is that the client doesn't have to establish a new connection
* upon each request. On the other hand, the client must be ready to
* re-establish a connection if we hang it up due to reaching of maximum
* number of requests per connection or due to the client timing out.
*/
while (keep_on_going) {
ipc_callid_t callid;
ipc_call_t call;
callid = async_get_call(&call);
switch (IPC_GET_METHOD(call)) {
case IPC_M_PHONE_HUNGUP:
keep_on_going = false;
break;
case VFS_REGISTER:
vfs_register(callid, &call);
keep_on_going = false;
break;
case VFS_MOUNT:
case VFS_UNMOUNT:
case VFS_OPEN:
case VFS_CREATE:
case VFS_CLOSE:
case VFS_READ:
case VFS_WRITE:
case VFS_SEEK:
default:
ipc_answer_fast(callid, ENOTSUP, 0, 0);
break;
}
}
/* TODO: cleanup after the client */
}
int main(int argc, char **argv)
{
ipcarg_t phonead;
list_initialize(&fs_head);
async_set_client_connection(vfs_connection);
ipc_connect_to_me(PHONE_NS, SERVICE_VFS, 0, &phonead);
async_manager();
return 0;
}
/**
* @}
*/