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/*

 * Copyright (c) 2008 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 libfs

 * @{

 */

/**

 * @file

 * Glue code which is commonod to all FS implementations.

 */

#include "libfs.h" 

#include "../../srv/vfs/vfs.h"

#include <errno.h>

#include <async.h>

#include <ipc/ipc.h>

#include <as.h>

#include <assert.h>

#include <dirent.h>

/** Register file system server.

 *

 * This function abstracts away the tedious registration protocol from

 * file system implementations and lets them to reuse this registration glue

 * code.

 *

 * @param vfs_phone Open phone for communication with VFS.

 * @param reg       File system registration structure. It will be

 *          initialized by this function.

 * @param info      VFS info structure supplied by the file system

 *          implementation.

 * @param conn      Connection fibril for handling all calls originating in

 *          VFS.

 *

 * @return      EOK on success or a non-zero error code on errror.

 */

int fs_register(int vfs_phone, fs_reg_t *reg, vfs_info_t *info,

    async_client_conn_t conn)

{

    /*

     * Tell VFS that we are here and want to get registered.

     * We use the async framework because VFS will answer the request

     * out-of-order, when it knows that the operation succeeded or failed.

     */

    ipc_call_t answer;

    aid_t req = async_send_0(vfs_phone, VFS_REGISTER, &answer);

    /*

     * Send our VFS info structure to VFS.

     */

    int rc = ipc_data_write_start(vfs_phone, info, sizeof(*info));

    if (rc != EOK) {

        async_wait_for(req, NULL);

        return rc;

    }

    /*

     * Ask VFS for callback connection.

     */

    ipc_connect_to_me(vfs_phone, 0, 0, 0, &reg->vfs_phonehash);

    /*

     * Allocate piece of address space for PLB.

     */

    reg->plb_ro = as_get_mappable_page(PLB_SIZE);

    if (!reg->plb_ro) {

        async_wait_for(req, NULL);

        return ENOMEM;

    }

    /*

     * Request sharing the Path Lookup Buffer with VFS.

     */

    rc = ipc_share_in_start_0_0(vfs_phone, reg->plb_ro, PLB_SIZE);

    if (rc) {

        async_wait_for(req, NULL);

        return rc;

    }

    /*

     * Pick up the answer for the request to the VFS_REQUEST call.

     */

    async_wait_for(req, NULL);

    reg->fs_handle = (int) IPC_GET_ARG1(answer);

    /*

     * Create a connection fibril to handle the callback connection.

     */

    async_new_connection(reg->vfs_phonehash, 0, NULL, conn);

    /*

     * Tell the async framework that other connections are to be handled by

     * the same connection fibril as well.

     */

    async_set_client_connection(conn);

    return IPC_GET_RETVAL(answer);

}

/** Lookup VFS triplet by name in the file system name space.

 *

 * The path passed in the PLB must be in the canonical file system path format

 * as returned by the canonify() function.

 *

 * @param ops       libfs operations structure with function pointers to

 *          file system implementation

 * @param fs_handle File system handle of the file system where to perform

 *          the lookup.

 * @param rid       Request ID of the VFS_LOOKUP request.

 * @param request   VFS_LOOKUP request data itself.

 */

void libfs_lookup(libfs_ops_t *ops, fs_handle_t fs_handle, ipc_callid_t rid,

    ipc_call_t *request)

{

    unsigned next = IPC_GET_ARG1(*request);

    unsigned last = IPC_GET_ARG2(*request);

    dev_handle_t dev_handle = IPC_GET_ARG3(*request);

    int lflag = IPC_GET_ARG4(*request);

    fs_index_t index = IPC_GET_ARG5(*request); /* when L_LINK specified */

    char component[NAME_MAX + 1];

    int len;

    if (last < next)

        last += PLB_SIZE;

    void *par = NULL;

    void *cur = ops->root_get(dev_handle);

    void *tmp = NULL;

    if (ops->plb_get_char(next) == '/')

        next++;     /* eat slash */

    while (next <= last && ops->has_children(cur)) {

        /* collect the component */

        len = 0;

        while ((next <= last) &&  (ops->plb_get_char(next) != '/')) {

            if (len + 1 == NAME_MAX) {

                /* component length overflow */

                ipc_answer_0(rid, ENAMETOOLONG);

                goto out;

            }

            component[len++] = ops->plb_get_char(next);

            next++; /* process next character */

        }

        assert(len);

        component[len] = '\0';

        next++;     /* eat slash */

        /* match the component */

        tmp = ops->match(cur, component);

        /* handle miss: match amongst siblings */

        if (!tmp) {

            if (next <= last) {

                /* there are unprocessed components */

                ipc_answer_0(rid, ENOENT);

                goto out;

            }

            /* miss in the last component */

            if (lflag & (L_CREATE | L_LINK)) {

                /* request to create a new link */

                if (!ops->is_directory(cur)) {

                    ipc_answer_0(rid, ENOTDIR);

                    goto out;

                }

                void *nodep;

                if (lflag & L_CREATE)

                    nodep = ops->create(lflag);

                else

                    nodep = ops->node_get(dev_handle,

                        index);

                if (nodep) {

                    if (!ops->link(cur, nodep, component)) {

                        if (lflag & L_CREATE) {

                            (void)ops->destroy(

                                nodep);

                        }

                        ipc_answer_0(rid, ENOSPC);

                    } else {

                        ipc_answer_5(rid, EOK,

                            fs_handle, dev_handle,

                            ops->index_get(nodep),

                            ops->size_get(nodep),

                            ops->lnkcnt_get(nodep));

                        ops->node_put(nodep);

                    }

                } else {

                    ipc_answer_0(rid, ENOSPC);

                }

                goto out;

            } else if (lflag & L_PARENT) {

                /* return parent */

                ipc_answer_5(rid, EOK, fs_handle, dev_handle,

                    ops->index_get(cur), ops->size_get(cur),

                    ops->lnkcnt_get(cur));

            }

            ipc_answer_0(rid, ENOENT);

            goto out;

        }

        if (par)

            ops->node_put(par);

        /* descend one level */

        par = cur;

        cur = tmp;

        tmp = NULL;

    }

    /* handle miss: excessive components */

    if (next <= last && !ops->has_children(cur)) {

        if (lflag & (L_CREATE | L_LINK)) {

            if (!ops->is_directory(cur)) {

                ipc_answer_0(rid, ENOTDIR);

                goto out;

            }

            /* collect next component */

            len = 0;

            while (next <= last) {

                if (ops->plb_get_char(next) == '/') {

                    /* more than one component */

                    ipc_answer_0(rid, ENOENT);

                    goto out;

                }

                if (len + 1 == NAME_MAX) {

                    /* component length overflow */

                    ipc_answer_0(rid, ENAMETOOLONG);

                    goto out;

                }

                component[len++] = ops->plb_get_char(next);

                next++; /* process next character */

            }

            assert(len);

            component[len] = '\0';

            void *nodep;

            if (lflag & L_CREATE)

                nodep = ops->create(lflag);

            else

                nodep = ops->node_get(dev_handle, index);

            if (nodep) {

                if (!ops->link(cur, nodep, component)) {

                    if (lflag & L_CREATE)

                        (void)ops->destroy(nodep);

                    ipc_answer_0(rid, ENOSPC);

                } else {

                    ipc_answer_5(rid, EOK,

                        fs_handle, dev_handle,

                        ops->index_get(nodep),

                        ops->size_get(nodep),

                        ops->lnkcnt_get(nodep));

                    ops->node_put(nodep);

                }

            } else {

                ipc_answer_0(rid, ENOSPC);

            }

            goto out;

        }

        ipc_answer_0(rid, ENOENT);

        goto out;

    }

    /* handle hit */

    if (lflag & L_PARENT) {

        ops->node_put(cur);

        cur = par;

        par = NULL;

        if (!cur) {

            ipc_answer_0(rid, ENOENT);

            goto out;

        }

    }

    if (lflag & L_UNLINK) {

        unsigned old_lnkcnt = ops->lnkcnt_get(cur);

        int res = ops->unlink(par, cur);

        ipc_answer_5(rid, (ipcarg_t)res, fs_handle, dev_handle,

            ops->index_get(cur), ops->size_get(cur), old_lnkcnt);

        goto out;

    }

    if (((lflag & (L_CREATE | L_EXCLUSIVE)) == (L_CREATE | L_EXCLUSIVE)) ||

        (lflag & L_LINK)) {

        ipc_answer_0(rid, EEXIST);

        goto out;

    }

    if ((lflag & L_FILE) && (ops->is_directory(cur))) {

        ipc_answer_0(rid, EISDIR);

        goto out;

    }

    if ((lflag & L_DIRECTORY) && (ops->is_file(cur))) {

        ipc_answer_0(rid, ENOTDIR);

        goto out;

    }

    ipc_answer_5(rid, EOK, fs_handle, dev_handle, ops->index_get(cur),

        ops->size_get(cur), ops->lnkcnt_get(cur));

out:

    if (par)

        ops->node_put(par);

    if (cur)

        ops->node_put(cur);

    if (tmp)

        ops->node_put(tmp);

}

/** @}

 */