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/*
* Copyright (c) 2007 Josef Cejka
* 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.
*/
/**
* @defgroup devmap Device mapper.
* @brief HelenOS device mapper.
* @{
*/
/** @file
*/
#include <ipc/services.h>
#include <ipc/ns.h>
#include <async.h>
#include <stdio.h>
#include <errno.h>
#include <bool.h>
#include <futex.h>
#include <stdlib.h>
#include <string.h>
#include <ipc/devmap.h>
#define NAME "devmap"
/** Pending lookup structure. */
typedef struct {
link_t link;
char *name; /**< Device name */
ipc_callid_t callid; /**< Call ID waiting for the lookup */
} pending_req_t;
LIST_INITIALIZE(devices_list);
LIST_INITIALIZE(drivers_list);
LIST_INITIALIZE(pending_req);
/* Locking order:
* drivers_list_futex
* devices_list_futex
* (devmap_driver_t *)->devices_futex
* create_handle_futex
**/
static atomic_t devices_list_futex = FUTEX_INITIALIZER;
static atomic_t drivers_list_futex = FUTEX_INITIALIZER;
static atomic_t create_handle_futex = FUTEX_INITIALIZER;
static int devmap_create_handle(void)
{
static int last_handle = 0;
int handle;
/* TODO: allow reusing old handles after their unregistration
* and implement some version of LRU algorithm
*/
/* FIXME: overflow */
futex_down(&create_handle_futex);
last_handle += 1;
handle = last_handle;
futex_up(&create_handle_futex);
return handle;
}
/** Initialize device mapper.
*
*
*/
static int devmap_init()
{
/* TODO: */
return EOK;
}
/** Find device with given name.
*
*/
static devmap_device_t *devmap_device_find_name(const char *name)
{
link_t *item = devices_list.next;
devmap_device_t *device = NULL;
while (item != &devices_list) {
device = list_get_instance(item, devmap_device_t, devices);
if (0 == strcmp(device->name, name))
break;
item = item->next;
}
if (item == &devices_list)
return NULL;
device = list_get_instance(item, devmap_device_t, devices);
return device;
}
/** Find device with given handle.
*
* @todo: use hash table
*
*/
static devmap_device_t *devmap_device_find_handle(int handle)
{
futex_down(&devices_list_futex);
link_t *item = (&devices_list)->next;
devmap_device_t *device = NULL;
while (item != &devices_list) {
device = list_get_instance(item, devmap_device_t, devices);
if (device->handle == handle)
break;
item = item->next;
}
if (item == &devices_list) {
futex_up(&devices_list_futex);
return NULL;
}
device = list_get_instance(item, devmap_device_t, devices);
futex_up(&devices_list_futex);
return device;
}
/**
*
* Unregister device and free it. It's assumed that driver's device list is
* already locked.
*
*/
static int devmap_device_unregister_core(devmap_device_t *device)
{
list_remove(&(device->devices));
list_remove(&(device->driver_devices));
free(device->name);
free(device);
return EOK;
}
/**
*
* Read info about new driver and add it into linked list of registered
* drivers.
*
*/
static void devmap_driver_register(devmap_driver_t **odriver)
{
*odriver = NULL;
ipc_call_t icall;
ipc_callid_t iid = async_get_call(&icall);
if (IPC_GET_METHOD(icall) != DEVMAP_DRIVER_REGISTER) {
ipc_answer_0(iid, EREFUSED);
return;
}
devmap_driver_t *driver = (devmap_driver_t *) malloc(sizeof(devmap_driver_t));
if (driver == NULL) {
ipc_answer_0(iid, ENOMEM);
return;
}
/*
* Get driver name
*/
ipc_callid_t callid;
size_t name_size;
if (!ipc_data_write_receive(&callid, &name_size)) {
free(driver);
ipc_answer_0(callid, EREFUSED);
ipc_answer_0(iid, EREFUSED);
return;
}
if (name_size > DEVMAP_NAME_MAXLEN) {
free(driver);
ipc_answer_0(callid, EINVAL);
ipc_answer_0(iid, EREFUSED);
return;
}
/*
* Allocate buffer for device name.
*/
driver->name = (char *) malloc(name_size + 1);
if (driver->name == NULL) {
free(driver);
ipc_answer_0(callid, ENOMEM);
ipc_answer_0(iid, EREFUSED);
return;
}
/*
* Send confirmation to sender and get data into buffer.
*/
if (EOK != ipc_data_write_finalize(callid, driver->name, name_size)) {
free(driver->name);
free(driver);
ipc_answer_0(iid, EREFUSED);
return;
}
driver->name[name_size] = 0;
/* Initialize futex for list of devices owned by this driver */
futex_initialize(&(driver->devices_futex), 1);
/*
* Initialize list of asociated devices
*/
list_initialize(&(driver->devices));
/*
* Create connection to the driver
*/
ipc_call_t call;
callid = async_get_call(&call);
if (IPC_M_CONNECT_TO_ME != IPC_GET_METHOD(call)) {
ipc_answer_0(callid, ENOTSUP);
free(driver->name);
free(driver);
ipc_answer_0(iid, ENOTSUP);
return;
}
driver->phone = IPC_GET_ARG5(call);
ipc_answer_0(callid, EOK);
list_initialize(&(driver->drivers));
futex_down(&drivers_list_futex);
/* TODO:
* check that no driver with name equal to driver->name is registered
*/
/*
* Insert new driver into list of registered drivers
*/
list_append(&(driver->drivers), &drivers_list);
futex_up(&drivers_list_futex);
ipc_answer_0(iid, EOK);
*odriver = driver;
}
/**
* Unregister device driver, unregister all its devices and free driver
* structure.
*
*/
static int devmap_driver_unregister(devmap_driver_t *driver)
{
if (driver == NULL)
return EEXISTS;
futex_down(&drivers_list_futex);
ipc_hangup(driver->phone);
/* remove it from list of drivers */
list_remove(&(driver->drivers));
/* unregister all its devices */
futex_down(&devices_list_futex);
futex_down(&(driver->devices_futex));
while (!list_empty(&(driver->devices))) {
devmap_device_t *device = list_get_instance(driver->devices.next,
devmap_device_t, driver_devices);
devmap_device_unregister_core(device);
}
futex_up(&(driver->devices_futex));
futex_up(&devices_list_futex);
futex_up(&drivers_list_futex);
/* free name and driver */
if (NULL != driver->name)
free(driver->name);
free(driver);
return EOK;
}
/** Process pending lookup requests */
static void process_pending_lookup()
{
link_t *cur;
loop:
for (cur = pending_req.next; cur != &pending_req; cur = cur->next) {
pending_req_t *pr = list_get_instance(cur, pending_req_t, link);
const devmap_device_t *dev = devmap_device_find_name(pr->name);
if (!dev)
continue;
ipc_answer_1(pr->callid, EOK, dev->handle);
free(pr->name);
list_remove(cur);
free(pr);
goto loop;
}
}
/** Register instance of device
*
*/
static void devmap_device_register(ipc_callid_t iid, ipc_call_t *icall,
devmap_driver_t *driver)
{
if (driver == NULL) {
ipc_answer_0(iid, EREFUSED);
return;
}
/* Create new device entry */
devmap_device_t *device = (devmap_device_t *) malloc(sizeof(devmap_device_t));
if (device == NULL) {
ipc_answer_0(iid, ENOMEM);
return;
}
/* Get device name */
ipc_callid_t callid;
size_t size;
if (!ipc_data_write_receive(&callid, &size)) {
free(device);
ipc_answer_0(iid, EREFUSED);
return;
}
if (size > DEVMAP_NAME_MAXLEN) {
free(device);
ipc_answer_0(callid, EINVAL);
ipc_answer_0(iid, EREFUSED);
return;
}
/* +1 for terminating \0 */
device->name = (char *) malloc(size + 1);
if (device->name == NULL) {
free(device);
ipc_answer_0(callid, ENOMEM);
ipc_answer_0(iid, EREFUSED);
return;
}
ipc_data_write_finalize(callid, device->name, size);
device->name[size] = 0;
list_initialize(&(device->devices));
list_initialize(&(device->driver_devices));
futex_down(&devices_list_futex);
/* Check that device with such name is not already registered */
if (NULL != devmap_device_find_name(device->name)) {
printf(NAME ": Device '%s' already registered\n", device->name);
futex_up(&devices_list_futex);
free(device->name);
free(device);
ipc_answer_0(iid, EEXISTS);
return;
}
/* Get unique device handle */
device->handle = devmap_create_handle();
device->driver = driver;
/* Insert device into list of all devices */
list_append(&device->devices, &devices_list);
/* Insert device into list of devices that belog to one driver */
futex_down(&device->driver->devices_futex);
list_append(&device->driver_devices, &device->driver->devices);
futex_up(&device->driver->devices_futex);
futex_up(&devices_list_futex);
ipc_answer_1(iid, EOK, device->handle);
process_pending_lookup();
}
/**
*
*/
static int devmap_device_unregister(ipc_callid_t iid, ipc_call_t *icall,
devmap_driver_t *driver)
{
/* TODO */
return EOK;
}
/** Connect client to the device.
*
* Find device driver owning requested device and forward
* the message to it.
*
*/
static void devmap_forward(ipc_callid_t callid, ipc_call_t *call)
{
/*
* Get handle from request
*/
int handle = IPC_GET_ARG2(*call);
devmap_device_t *dev = devmap_device_find_handle(handle);
if (NULL == dev) {
ipc_answer_0(callid, ENOENT);
return;
}
ipc_forward_fast(callid, dev->driver->phone, (ipcarg_t)(dev->handle),
IPC_GET_ARG3(*call), 0, IPC_FF_NONE);
}
/** Find handle for device instance identified by name.
*
* In answer will be send EOK and device handle in arg1 or a error
* code from errno.h.
*
*/
static void devmap_get_handle(ipc_callid_t iid, ipc_call_t *icall)
{
/*
* Wait for incoming message with device name (but do not
* read the name itself until the buffer is allocated).
*/
ipc_callid_t callid;
size_t size;
if (!ipc_data_write_receive(&callid, &size)) {
ipc_answer_0(callid, EREFUSED);
ipc_answer_0(iid, EREFUSED);
return;
}
if ((size < 1) || (size > DEVMAP_NAME_MAXLEN)) {
ipc_answer_0(callid, EINVAL);
ipc_answer_0(iid, EREFUSED);
return;
}
/*
* Allocate buffer for device name.
*/
char *name = (char *) malloc(size);
if (name == NULL) {
ipc_answer_0(callid, ENOMEM);
ipc_answer_0(iid, EREFUSED);
return;
}
/*
* Send confirmation to sender and get data into buffer.
*/
ipcarg_t retval = ipc_data_write_finalize(callid, name, size);
if (retval != EOK) {
ipc_answer_0(iid, EREFUSED);
free(name);
return;
}
name[size] = '\0';
/*
* Find device name in linked list of known devices.
*/
const devmap_device_t *dev = devmap_device_find_name(name);
/*
* Device was not found.
*/
if (dev == NULL) {
if (IPC_GET_ARG1(*icall) & IPC_FLAG_BLOCKING) {
/* Blocking lookup, add to pending list */
pending_req_t *pr = (pending_req_t *) malloc(sizeof(pending_req_t));
if (!pr) {
ipc_answer_0(iid, ENOMEM);
free(name);
return;
}
pr->name = name;
pr->callid = iid;
list_append(&pr->link, &pending_req);
return;
}
ipc_answer_0(iid, ENOENT);
free(name);
return;
}
ipc_answer_1(iid, EOK, dev->handle);
free(name);
}
/** Find name of device identified by id and send it to caller.
*
*/
static void devmap_get_name(ipc_callid_t iid, ipc_call_t *icall)
{
const devmap_device_t *device = devmap_device_find_handle(IPC_GET_ARG1(*icall));
/*
* Device not found.
*/
if (device == NULL) {
ipc_answer_0(iid, ENOENT);
return;
}
ipc_answer_0(iid, EOK);
size_t name_size = strlen(device->name);
/* FIXME:
* We have no channel from DEVMAP to client, therefore
* sending must be initiated by client.
*
* int rc = ipc_data_write_send(phone, device->name, name_size);
* if (rc != EOK) {
* async_wait_for(req, NULL);
* return rc;
* }
*/
/* TODO: send name in response */
}
/** Handle connection with device driver.
*
*/
static void devmap_connection_driver(ipc_callid_t iid, ipc_call_t *icall)
{
/* Accept connection */
ipc_answer_0(iid, EOK);
devmap_driver_t *driver = NULL;
devmap_driver_register(&driver);
if (NULL == driver)
return;
bool cont = true;
while (cont) {
ipc_call_t call;
ipc_callid_t callid = async_get_call(&call);
switch (IPC_GET_METHOD(call)) {
case IPC_M_PHONE_HUNGUP:
cont = false;
/* Exit thread */
continue;
case DEVMAP_DRIVER_UNREGISTER:
if (NULL == driver)
ipc_answer_0(callid, ENOENT);
else
ipc_answer_0(callid, EOK);
break;
case DEVMAP_DEVICE_REGISTER:
/* Register one instance of device */
devmap_device_register(callid, &call, driver);
break;
case DEVMAP_DEVICE_UNREGISTER:
/* Remove instance of device identified by handler */
devmap_device_unregister(callid, &call, driver);
break;
case DEVMAP_DEVICE_GET_HANDLE:
devmap_get_handle(callid, &call);
break;
case DEVMAP_DEVICE_GET_NAME:
devmap_get_handle(callid, &call);
break;
default:
if (!(callid & IPC_CALLID_NOTIFICATION))
ipc_answer_0(callid, ENOENT);
}
}
if (NULL != driver) {
/*
* Unregister the device driver and all its devices.
*/
devmap_driver_unregister(driver);
driver = NULL;
}
}
/** Handle connection with device client.
*
*/
static void devmap_connection_client(ipc_callid_t iid, ipc_call_t *icall)
{
/* Accept connection */
ipc_answer_0(iid, EOK);
bool cont = true;
while (cont) {
ipc_call_t call;
ipc_callid_t callid = async_get_call(&call);
switch (IPC_GET_METHOD(call)) {
case IPC_M_PHONE_HUNGUP:
cont = false;
/* Exit thread */
continue;
case DEVMAP_DEVICE_GET_HANDLE:
devmap_get_handle(callid, &call);
break;
case DEVMAP_DEVICE_GET_NAME:
/* TODO */
devmap_get_name(callid, &call);
break;
default:
if (!(callid & IPC_CALLID_NOTIFICATION))
ipc_answer_0(callid, ENOENT);
}
}
}
/** Function for handling connections to devmap
*
*/
static void devmap_connection(ipc_callid_t iid, ipc_call_t *icall)
{
/* Select interface */
switch ((ipcarg_t) (IPC_GET_ARG1(*icall))) {
case DEVMAP_DRIVER:
devmap_connection_driver(iid, icall);
break;
case DEVMAP_CLIENT:
devmap_connection_client(iid, icall);
break;
case DEVMAP_CONNECT_TO_DEVICE:
/* Connect client to selected device */
devmap_forward(iid, icall);
break;
default:
/* No such interface */
ipc_answer_0(iid, ENOENT);
}
}
/**
*
*/
int main(int argc, char *argv[])
{
printf(NAME ": HelenOS Device Mapper\n");
if (devmap_init() != 0) {
printf(NAME ": Error while initializing service\n");
return -1;
}
/* Set a handler of incomming connections */
async_set_client_connection(devmap_connection);
/* Register device mapper at naming service */
ipcarg_t phonead;
if (ipc_connect_to_me(PHONE_NS, SERVICE_DEVMAP, 0, 0, &phonead) != 0)
return -1;
printf(NAME ": Accepting connections\n");
async_manager();
/* Never reached */
return 0;
}
/**
* @}
*/