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2560 jermar 1 
/*
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 * Copyright (c) 2007 Jakub Jermar
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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/** @addtogroup fs
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 * @{
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 */
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/**
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 * @file    vfs_open.c
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 * @brief   VFS_OPEN method.
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 */
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#include <ipc/ipc.h>
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#include <async.h>
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#include <errno.h>
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#include <rwlock.h>
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#include <sys/types.h>
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#include <stdlib.h>
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#include "vfs.h"
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void vfs_open(ipc_callid_t rid, ipc_call_t *request)
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{
2593 jermar 48 
    if (!vfs_files_init()) {
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        ipc_answer_0(rid, ENOMEM);
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        return;
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    }
2590 jermar 52 
 
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    /*
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     * The POSIX interface is open(path, flags, mode).
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     * We can receive flags and mode along with the VFS_OPEN call; the path
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     * will need to arrive in another call.
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     */
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    int flags = IPC_GET_ARG1(*request);
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    int mode = IPC_GET_ARG2(*request);
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    size_t len;
2590 jermar 61 
 
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    ipc_callid_t callid;
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2687 jermar 64 
    if (!ipc_data_write_receive(&callid, &len)) {
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        ipc_answer_0(callid, EINVAL);
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        ipc_answer_0(rid, EINVAL);
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        return;
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    }
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    /*
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     * Now we are on the verge of accepting the path.
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     *
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     * There is one optimization we could do in the future: copy the path
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     * directly into the PLB using some kind of a callback.
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     */
2687 jermar 76 
    char *path = malloc(len);
2590 jermar 77 
 
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    if (!path) {
2619 jermar 79 
        ipc_answer_0(callid, ENOMEM);
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        ipc_answer_0(rid, ENOMEM);
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        return;
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    }
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    int rc;
2687 jermar 85 
    if ((rc = ipc_data_write_finalize(callid, path, len))) {
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        ipc_answer_0(rid, rc);
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        free(path);
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        return;
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    }
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    /*
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     * Avoid the race condition in which the file can be deleted before we
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     * find/create-and-lock the VFS node corresponding to the looked-up
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     * triplet.
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     */
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    rwlock_read_lock(&namespace_rwlock);
2593 jermar 97 
 
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    /*
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     * The path is now populated and we can call vfs_lookup_internal().
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     */
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    vfs_triplet_t triplet;
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    size_t size;
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    rc = vfs_lookup_internal(path, len, &triplet, &size, NULL);
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    if (rc) {
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        rwlock_read_unlock(&namespace_rwlock);
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        ipc_answer_0(rid, rc);
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        free(path);
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        return;
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    }
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    /*
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     * Path is no longer needed.
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     */
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    free(path);
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    vfs_node_t *node = vfs_node_get(&triplet, size);
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    rwlock_read_unlock(&namespace_rwlock);
2593 jermar 118 
 
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    /*
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     * Get ourselves a file descriptor and the corresponding vfs_file_t
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     * structure.
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     */
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    int fd = vfs_fd_alloc();
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    if (fd < 0) {
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        vfs_node_put(node);
2619 jermar 126 
        ipc_answer_0(rid, fd);
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        return;
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    }
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    vfs_file_t *file = vfs_file_get(fd);
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    file->node = node;
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    /*
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     * The following increase in reference count is for the fact that the
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     * file is being opened and that a file structure is pointing to it.
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     * It is necessary so that the file will not disappear when
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     * vfs_node_put() is called. The reference will be dropped by the
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     * respective VFS_CLOSE.
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     */
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    vfs_node_addref(node);
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    vfs_node_put(node);
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    /*
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     * Success! Return the new file descriptor to the client.
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     */
2619 jermar 145 
    ipc_answer_1(rid, EOK, fd);
2560 jermar 146 
}
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/**
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 * @}
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 */