WebSVN – HelenOS – Diff – /branches/dynload/uspace/srv/devmap/devmap.c

  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 /**
  * @defgroup devmap Device mapper.
- * @brief   HelenOS device mapper.
+ * @brief HelenOS device mapper.
  * @{
  */
 /** @file
  */
 #include <ipc/services.h>
 #include <futex.h>
 #include <stdlib.h>
 #include <string.h>
 #include <ipc/devmap.h>
-#define NAME "devmap"
+#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);
-/* order of locking:
+/* Locking order:
- * drivers_list_futex
+ *  drivers_list_futex
- * devices_list_futex
+ *  devices_list_futex
- * (devmap_driver_t *)->devices_futex
+ *  (devmap_driver_t *)->devices_futex
- * create_handle_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 */
+     * 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;
+    link_t *item = devices_list.next;
     devmap_device_t *device = NULL;
-    item = devices_list.next;
     while (item != &devices_list) {
         device = list_get_instance(item, devmap_device_t, devices);
-        if (0 == strcmp(device->name, name)) {
+        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;
+    link_t *item = (&devices_list)->next;
     devmap_device_t *device = NULL;
-    futex_down(&devices_list_futex);
-    item = (&devices_list)->next;
     while (item != &devices_list) {
         device = list_get_instance(item, devmap_device_t, devices);
-        if (device->handle == handle) {
+        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)
+{
-    size_t name_size;
-    ipc_callid_t callid;
-    ipc_call_t call;
-    devmap_driver_t *driver;
-    ipc_callid_t iid;
-    ipc_call_t icall;
     *odriver = NULL;
+    ipc_call_t icall;
-    iid = async_get_call(&icall);
+    ipc_callid_t iid = async_get_call(&icall);
     if (IPC_GET_METHOD(icall) != DEVMAP_DRIVER_REGISTER) {
         ipc_answer_0(iid, EREFUSED);
         return;
     }
-    if (NULL ==
-        (driver = (devmap_driver_t *)malloc(sizeof(devmap_driver_t)))) {
+    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.
      */
-    if (NULL == (driver->name = (char *)malloc(name_size + 1))) {
+    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
+ * Unregister device driver, unregister all its devices and free driver
  * structure.
+ *
  */
 static int devmap_driver_unregister(devmap_driver_t *driver)
+{
-    devmap_device_t *device;
-    if (NULL == 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))) {
-        device = list_get_instance(driver->devices.next,
+        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) {
+    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)
+{
-    ipc_callid_t callid;
-    size_t size;
-    devmap_device_t *device;
-    if (NULL == driver) {
+    if (driver == NULL) {
         ipc_answer_0(iid, EREFUSED);
         return;
+    }
     /* Create new device entry */
-    if (NULL ==
-        (device = (devmap_device_t *) malloc(sizeof(devmap_device_t)))) {
+    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 (NULL == device->name) {
+    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)
+{
-    devmap_device_t *dev;
-    int handle;
     /*
      * Get handle from request
      */
-    handle = IPC_GET_ARG2(*call);
+    int handle = IPC_GET_ARG2(*call);
-    dev = devmap_device_find_handle(handle);
+    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)
+{
-    char *name = NULL;
-    size_t name_size;
-    const devmap_device_t *dev;
-    ipc_callid_t callid;
-    ipcarg_t retval;
     /*
      * 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, &name_size)) {
+    if (!ipc_data_write_receive(&callid, &size)) {
         ipc_answer_0(callid, EREFUSED);
         ipc_answer_0(iid, EREFUSED);
         return;
+    }
-    if (name_size > DEVMAP_NAME_MAXLEN) {
+    if ((size < 1) || (size > DEVMAP_NAME_MAXLEN)) {
         ipc_answer_0(callid, EINVAL);
         ipc_answer_0(iid, EREFUSED);
         return;
+    }
     /*
      * Allocate buffer for device name.
      */
-    if (NULL == (name = (char *)malloc(name_size))) {
+    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.
      */
-    if (EOK != (retval = ipc_data_write_finalize(callid, name,
+    ipcarg_t retval = ipc_data_write_finalize(callid, name, size);
-        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.
      */
-    dev = devmap_device_find_name(name);
+    const devmap_device_t *dev = devmap_device_find_name(name);
     /*
      * Device was not found.
      */
-    if (NULL == dev) {
+    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;
-    size_t name_size;
-    device = devmap_device_find_handle(IPC_GET_ARG1(*icall));
+    const devmap_device_t *device = devmap_device_find_handle(IPC_GET_ARG1(*icall));
     /*
      * Device not found.
      */
-    if (NULL == device) {
+    if (device == NULL) {
         ipc_answer_0(iid, ENOENT);
         return;
-    }
-    ipc_answer_0(iid, EOK);
-    name_size = strlen(device->name);
-/*  FIXME:
-    we have no channel from DEVMAP to client ->
-    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;
+    }
+    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)
+{
-    ipc_callid_t callid;
+    /* Accept connection */
-    ipc_call_t call;
+    ipc_answer_0(iid, EOK);
-    bool cont = true;
     devmap_driver_t *driver = NULL;
-    ipc_answer_0(iid, EOK);
     devmap_driver_register(&driver);
     if (NULL == driver)
         return;
+    bool cont = true;
     while (cont) {
+        ipc_call_t call;
-        callid = async_get_call(&call);
+        ipc_callid_t callid = async_get_call(&call);
         switch (IPC_GET_METHOD(call)) {
         case IPC_M_PHONE_HUNGUP:
             cont = false;
-            continue; /* Exit thread */
+            /* Exit thread */
+            continue;
         case DEVMAP_DRIVER_UNREGISTER:
-            if (NULL == driver) {
+            if (NULL == driver)
                 ipc_answer_0(callid, ENOENT);
-            } else {
+            else
                 ipc_answer_0(callid, EOK);
-            }
             break;
         case DEVMAP_DEVICE_REGISTER:
             /* Register one instance of device */
             devmap_device_register(callid, &call, driver);
             break;
             break;
         case DEVMAP_DEVICE_GET_NAME:
             devmap_get_handle(callid, &call);
             break;
         default:
-            if (!(callid & IPC_CALLID_NOTIFICATION)) {
+            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)
+{
-    ipc_callid_t callid;
+    /* Accept connection */
-    ipc_call_t call;
+    ipc_answer_0(iid, EOK);
     bool cont = true;
-    ipc_answer_0(iid, EOK); /* Accept connection */
     while (cont) {
+        ipc_call_t call;
-        callid = async_get_call(&call);
+        ipc_callid_t callid = async_get_call(&call);
         switch (IPC_GET_METHOD(call)) {
         case IPC_M_PHONE_HUNGUP:
             cont = false;
-            continue; /* Exit thread */
+            /* 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)) {
+            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 */
     case DEVMAP_CONNECT_TO_DEVICE:
         /* Connect client to selected device */
         devmap_forward(iid, icall);
         break;
     default:
+        /* No such interface */
-        ipc_answer_0(iid, ENOENT); /* No such interface */
+        ipc_answer_0(iid, ENOENT);
+    }
-    /* Cleanup */
+}
 /**
+ *
  */
 int main(int argc, char *argv[])
+{
     printf(NAME ": HelenOS Device Mapper\n");
-    ipcarg_t phonead;
     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;
+}
 /**

Subversion Repositories HelenOS

(root)/branches/dynload/uspace/srv/devmap/devmap.c – Rev 3150 → 4345