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/*

 * Copyright (c) 2009 Martin Decky

 * 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 devfs_ops.c

 * @brief Implementation of VFS operations for the devfs file system server.

 */

#include <ipc/ipc.h>

#include <bool.h>

#include <errno.h>

#include <malloc.h>

#include <string.h>

#include <libfs.h>

#include <fibril_sync.h>

#include <adt/hash_table.h>

#include <sys/stat.h>

#include "devfs.h"

#include "devfs_ops.h"

#define PLB_GET_CHAR(pos)  (devfs_reg.plb_ro[pos % PLB_SIZE])

/** Opened devices structure */

typedef struct {

    dev_handle_t handle;

    int phone;

    size_t refcount;

    link_t link;

} device_t;

/** Hash table of opened devices */

static hash_table_t devices;

/** Hash table mutex */

static FIBRIL_MUTEX_INITIALIZE(devices_mutex);

#define DEVICES_KEYS        1

#define DEVICES_KEY_HANDLE  0

#define DEVICES_BUCKETS     256

/* Implementation of hash table interface for the nodes hash table. */

static hash_index_t devices_hash(unsigned long key[])

{

    return key[DEVICES_KEY_HANDLE] % DEVICES_BUCKETS;

}

static int devices_compare(unsigned long key[], hash_count_t keys, link_t *item)

{

    device_t *dev = hash_table_get_instance(item, device_t, link);

    return (dev->handle == (dev_handle_t) key[DEVICES_KEY_HANDLE]);

}

static void devices_remove_callback(link_t *item)

{

    free(hash_table_get_instance(item, device_t, link));

}

static hash_table_operations_t devices_ops = {

    .hash = devices_hash,

    .compare = devices_compare,

    .remove_callback = devices_remove_callback

};

bool devfs_init(void)

{

    if (!hash_table_create(&devices, DEVICES_BUCKETS,

        DEVICES_KEYS, &devices_ops))

        return false;

    if (devmap_get_phone(DEVMAP_CLIENT, IPC_FLAG_BLOCKING) < 0)

        return false;

    return true;

}

void devfs_mounted(ipc_callid_t rid, ipc_call_t *request)

{

    /* Accept the mount options */

    ipc_callid_t callid;

    size_t size;

    if (!ipc_data_write_receive(&callid, &size)) {

        ipc_answer_0(callid, EINVAL);

        ipc_answer_0(rid, EINVAL);

        return;

    }

    char *opts = malloc(size + 1);

    if (!opts) {

        ipc_answer_0(callid, ENOMEM);

        ipc_answer_0(rid, ENOMEM);

        return;

    }

    ipcarg_t retval = ipc_data_write_finalize(callid, opts, size);

    if (retval != EOK) {

        ipc_answer_0(rid, retval);

        free(opts);

        return;

    }

    free(opts);

    ipc_answer_3(rid, EOK, 0, 0, 0);

}

void devfs_mount(ipc_callid_t rid, ipc_call_t *request)

{

    ipc_answer_0(rid, ENOTSUP);

}

void devfs_lookup(ipc_callid_t rid, ipc_call_t *request)

{

    ipcarg_t first = IPC_GET_ARG1(*request);

    ipcarg_t last = IPC_GET_ARG2(*request);

    dev_handle_t dev_handle = IPC_GET_ARG3(*request);

    ipcarg_t lflag = IPC_GET_ARG4(*request);

    fs_index_t index = IPC_GET_ARG5(*request);

    /* Hierarchy is flat, no altroot is supported */

    if (index != 0) {

        ipc_answer_0(rid, ENOENT);

        return;

    }

    if ((lflag & L_LINK) || (lflag & L_UNLINK)) {

        ipc_answer_0(rid, ENOTSUP);

        return;

    }

    /* Eat slash */

    if (PLB_GET_CHAR(first) == '/') {

        first++;

        first %= PLB_SIZE;

    }

    if (first >= last) {

        /* Root entry */

        if (!(lflag & L_FILE))

            ipc_answer_5(rid, EOK, devfs_reg.fs_handle, dev_handle, 0, 0, 0);

        else

            ipc_answer_0(rid, ENOENT);

    } else {

        if (!(lflag & L_DIRECTORY)) {

            size_t len;

            if (last >= first)

                len = last - first + 1;

            else

                len = first + PLB_SIZE - last + 1;

            char *name = (char *) malloc(len + 1);

            if (name == NULL) {

                ipc_answer_0(rid, ENOMEM);

                return;

            }

            size_t i;

            for (i = 0; i < len; i++)

                name[i] = PLB_GET_CHAR(first + i);

            name[len] = 0;

            dev_handle_t handle;

            if (devmap_device_get_handle(name, &handle, 0) != EOK) {

                free(name);

                ipc_answer_0(rid, ENOENT);

                return;

            }

            if (lflag & L_OPEN) {

                unsigned long key[] = {

                    [DEVICES_KEY_HANDLE] = (unsigned long) handle

                };

                fibril_mutex_lock(&devices_mutex);

                link_t *lnk = hash_table_find(&devices, key);

                if (lnk == NULL) {

                    int phone = devmap_device_connect(handle, 0);

                    if (phone < 0) {

                        fibril_mutex_unlock(&devices_mutex);

                        free(name);

                        ipc_answer_0(rid, ENOENT);

                        return;

                    }

                    device_t *dev = (device_t *) malloc(sizeof(device_t));

                    if (dev == NULL) {

                        fibril_mutex_unlock(&devices_mutex);

                        free(name);

                        ipc_answer_0(rid, ENOMEM);

                        return;

                    }

                    dev->handle = handle;

                    dev->phone = phone;

                    dev->refcount = 1;

                    hash_table_insert(&devices, key, &dev->link);

                } else {

                    device_t *dev = hash_table_get_instance(lnk, device_t, link);

                    dev->refcount++;

                }

                fibril_mutex_unlock(&devices_mutex);

            }

            free(name);

            ipc_answer_5(rid, EOK, devfs_reg.fs_handle, dev_handle, handle, 0, 1);

        } else

            ipc_answer_0(rid, ENOENT);

    }

}

void devfs_open_node(ipc_callid_t rid, ipc_call_t *request)

{

    dev_handle_t handle = IPC_GET_ARG2(*request);

    unsigned long key[] = {

        [DEVICES_KEY_HANDLE] = (unsigned long) handle

    };

    fibril_mutex_lock(&devices_mutex);

    link_t *lnk = hash_table_find(&devices, key);

    if (lnk == NULL) {

        int phone = devmap_device_connect(handle, 0);

        if (phone < 0) {

            fibril_mutex_unlock(&devices_mutex);

            ipc_answer_0(rid, ENOENT);

            return;

        }

        device_t *dev = (device_t *) malloc(sizeof(device_t));

        if (dev == NULL) {

            fibril_mutex_unlock(&devices_mutex);

            ipc_answer_0(rid, ENOMEM);

            return;

        }

        dev->handle = handle;

        dev->phone = phone;

        dev->refcount = 1;

        hash_table_insert(&devices, key, &dev->link);

    } else {

        device_t *dev = hash_table_get_instance(lnk, device_t, link);

        dev->refcount++;

    }

    fibril_mutex_unlock(&devices_mutex);

    ipc_answer_3(rid, EOK, 0, 1, L_FILE);

}

void devfs_stat(ipc_callid_t rid, ipc_call_t *request)

{

    dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);

    fs_index_t index = (fs_index_t) IPC_GET_ARG2(*request);

    ipc_callid_t callid;

    size_t size;

    if (!ipc_data_read_receive(&callid, &size) ||

        size != sizeof(struct stat)) {

        ipc_answer_0(callid, EINVAL);

        ipc_answer_0(rid, EINVAL);

        return;

    }

    struct stat stat;

    memset(&stat, 0, sizeof(struct stat));

    stat.fs_handle = devfs_reg.fs_handle;

    stat.dev_handle = dev_handle;

    stat.index = index;

    stat.lnkcnt = 1;

    stat.is_file = (index != 0);

    stat.size = 0;

    if (index != 0) {

        unsigned long key[] = {

            [DEVICES_KEY_HANDLE] = (unsigned long) index

        };

        fibril_mutex_lock(&devices_mutex);

        link_t *lnk = hash_table_find(&devices, key);

        if (lnk != NULL)

            stat.devfs_stat.device = (dev_handle_t)index;

        fibril_mutex_unlock(&devices_mutex);

    }

    ipc_data_read_finalize(callid, &stat, sizeof(struct stat));

    ipc_answer_0(rid, EOK);

}

void devfs_read(ipc_callid_t rid, ipc_call_t *request)

{

    fs_index_t index = (fs_index_t) IPC_GET_ARG2(*request);

    off_t pos = (off_t) IPC_GET_ARG3(*request);

    if (index != 0) {

        unsigned long key[] = {

            [DEVICES_KEY_HANDLE] = (unsigned long) index

        };

        fibril_mutex_lock(&devices_mutex);

        link_t *lnk = hash_table_find(&devices, key);

        if (lnk == NULL) {

            fibril_mutex_unlock(&devices_mutex);

            ipc_answer_0(rid, ENOENT);

            return;

        }

        device_t *dev = hash_table_get_instance(lnk, device_t, link);

        ipc_callid_t callid;

        if (!ipc_data_read_receive(&callid, NULL)) {

            fibril_mutex_unlock(&devices_mutex);

            ipc_answer_0(callid, EINVAL);

            ipc_answer_0(rid, EINVAL);

            return;

        }

        /* Make a request at the driver */

        ipc_call_t answer;

        aid_t msg = async_send_3(dev->phone, IPC_GET_METHOD(*request),

            IPC_GET_ARG1(*request), IPC_GET_ARG2(*request),

            IPC_GET_ARG3(*request), &answer);

        /* Forward the IPC_M_DATA_READ request to the driver */

        ipc_forward_fast(callid, dev->phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);

        fibril_mutex_unlock(&devices_mutex);

        /* Wait for reply from the driver. */

        ipcarg_t rc;

        async_wait_for(msg, &rc);

        size_t bytes = IPC_GET_ARG1(answer);

        /* Driver reply is the final result of the whole operation */

        ipc_answer_1(rid, rc, bytes);

    } else {

        ipc_callid_t callid;

        size_t size;

        if (!ipc_data_read_receive(&callid, &size)) {

            ipc_answer_0(callid, EINVAL);

            ipc_answer_0(rid, EINVAL);

            return;

        }

        size_t count = devmap_device_get_count();

        dev_desc_t *desc = malloc(count * sizeof(dev_desc_t));

        if (desc == NULL) {

            ipc_answer_0(callid, ENOMEM);

            ipc_answer_1(rid, ENOMEM, 0);

            return;

        }

        size_t max = devmap_device_get_devices(count, desc);

        if (pos < max) {

            ipc_data_read_finalize(callid, desc[pos].name, str_size(desc[pos].name) + 1);

        } else {

            ipc_answer_0(callid, ENOENT);

            ipc_answer_1(rid, ENOENT, 0);

            return;

        }

        free(desc);

        ipc_answer_1(rid, EOK, 1);

    }

}

void devfs_write(ipc_callid_t rid, ipc_call_t *request)

{

    fs_index_t index = (fs_index_t) IPC_GET_ARG2(*request);

    off_t pos = (off_t) IPC_GET_ARG3(*request);

    if (index != 0) {

        unsigned long key[] = {

            [DEVICES_KEY_HANDLE] = (unsigned long) index

        };

        fibril_mutex_lock(&devices_mutex);

        link_t *lnk = hash_table_find(&devices, key);

        if (lnk == NULL) {

            fibril_mutex_unlock(&devices_mutex);

            ipc_answer_0(rid, ENOENT);

            return;

        }

        device_t *dev = hash_table_get_instance(lnk, device_t, link);

        ipc_callid_t callid;

        if (!ipc_data_write_receive(&callid, NULL)) {

            fibril_mutex_unlock(&devices_mutex);

            ipc_answer_0(callid, EINVAL);

            ipc_answer_0(rid, EINVAL);

            return;

        }

        /* Make a request at the driver */

        ipc_call_t answer;

        aid_t msg = async_send_3(dev->phone, IPC_GET_METHOD(*request),

            IPC_GET_ARG1(*request), IPC_GET_ARG2(*request),

            IPC_GET_ARG3(*request), &answer);

        /* Forward the IPC_M_DATA_WRITE request to the driver */

        ipc_forward_fast(callid, dev->phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);

        fibril_mutex_unlock(&devices_mutex);

        /* Wait for reply from the driver. */

        ipcarg_t rc;

        async_wait_for(msg, &rc);

        size_t bytes = IPC_GET_ARG1(answer);

        /* Driver reply is the final result of the whole operation */

        ipc_answer_1(rid, rc, bytes);

    } else {

        /* Read-only filesystem */

        ipc_answer_0(rid, ENOTSUP);

    }

}

void devfs_truncate(ipc_callid_t rid, ipc_call_t *request)

{

    ipc_answer_0(rid, ENOTSUP);

}

void devfs_close(ipc_callid_t rid, ipc_call_t *request)

{

    fs_index_t index = (fs_index_t) IPC_GET_ARG2(*request);

    if (index != 0) {

        unsigned long key[] = {

            [DEVICES_KEY_HANDLE] = (unsigned long) index

        };

        fibril_mutex_lock(&devices_mutex);

        link_t *lnk = hash_table_find(&devices, key);

        if (lnk == NULL) {

            fibril_mutex_unlock(&devices_mutex);

            ipc_answer_0(rid, ENOENT);

            return;

        }

        device_t *dev = hash_table_get_instance(lnk, device_t, link);

        dev->refcount--;

        if (dev->refcount == 0) {

            ipc_hangup(dev->phone);

            hash_table_remove(&devices, key, DEVICES_KEYS);

        }

        fibril_mutex_unlock(&devices_mutex);

        ipc_answer_0(rid, EOK);

    } else

        ipc_answer_0(rid, ENOTSUP);

}

void devfs_sync(ipc_callid_t rid, ipc_call_t *request)

{

    fs_index_t index = (fs_index_t) IPC_GET_ARG2(*request);

    if (index != 0) {

        unsigned long key[] = {

            [DEVICES_KEY_HANDLE] = (unsigned long) index

        };

        fibril_mutex_lock(&devices_mutex);

        link_t *lnk = hash_table_find(&devices, key);

        if (lnk == NULL) {

            fibril_mutex_unlock(&devices_mutex);

            ipc_answer_0(rid, ENOENT);

            return;

        }

        device_t *dev = hash_table_get_instance(lnk, device_t, link);

        /* Make a request at the driver */

        ipc_call_t answer;

        aid_t msg = async_send_2(dev->phone, IPC_GET_METHOD(*request),

            IPC_GET_ARG1(*request), IPC_GET_ARG2(*request), &answer);

        fibril_mutex_unlock(&devices_mutex);

        /* Wait for reply from the driver */

        ipcarg_t rc;

        async_wait_for(msg, &rc);

        /* Driver reply is the final result of the whole operation */

        ipc_answer_0(rid, rc);

    } else

        ipc_answer_0(rid, ENOTSUP);

}

void devfs_destroy(ipc_callid_t rid, ipc_call_t *request)

{

    ipc_answer_0(rid, ENOTSUP);

}

/**

 * @}

 */