WebSVN – HelenOS – Diff – /trunk/uspace/srv/vfs/vfs_ops.c


/*
 * 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 fs
 * @{
 */
 
/**
 * @file vfs_ops.c
 * @brief Operations that VFS offers to its clients.
 */
 
#include "vfs.h"
#include <ipc/ipc.h>
#include <async.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <bool.h>
#include <futex.h>
#include <rwlock.h>
#include <libadt/list.h>
#include <unistd.h>
#include <ctype.h>
#include <fcntl.h>
#include <assert.h>
#include <vfs/canonify.h>
 
/* Forward declarations of static functions. */
static int vfs_truncate_internal(fs_handle_t, dev_handle_t, fs_index_t, size_t);
 
/** Pending mount structure. */
typedef struct {
    link_t link;
    char *fs_name;            /**< File system name */
    char *mp;                 /**< Mount point */
    ipc_callid_t callid;      /**< Call ID waiting for the mount */
    ipc_callid_t rid;         /**< Request ID */
    dev_handle_t dev_handle;  /**< Device handle */
} pending_req_t;
 
LIST_INITIALIZE(pending_req);
 
/**
 * This rwlock prevents the race between a triplet-to-VFS-node resolution and a
 * concurrent VFS operation which modifies the file system namespace.
 */
RWLOCK_INITIALIZE(namespace_rwlock);
 
futex_t rootfs_futex = FUTEX_INITIALIZER;
vfs_pair_t rootfs = {
    .fs_handle = 0,
    .dev_handle = 0
};
 
static void vfs_mount_internal(ipc_callid_t rid, dev_handle_t dev_handle,
    fs_handle_t fs_handle, char *mp)
{
    /* Resolve the path to the mountpoint. */
    vfs_lookup_res_t mp_res;
    vfs_node_t *mp_node = NULL;
    int rc;
    int phone;
    futex_down(&rootfs_futex);
    if (rootfs.fs_handle) {
        /* We already have the root FS. */
        rwlock_write_lock(&namespace_rwlock);
        if (str_cmp(mp, "/") == 0) {
            /* Trying to mount root FS over root FS */
            rwlock_write_unlock(&namespace_rwlock);
            futex_up(&rootfs_futex);
            ipc_answer_0(rid, EBUSY);
            return;
        }
       
        rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);
        if (rc != EOK) {
            /* The lookup failed for some reason. */
            rwlock_write_unlock(&namespace_rwlock);
            futex_up(&rootfs_futex);
            ipc_answer_0(rid, rc);
            return;
        }
       
        mp_node = vfs_node_get(&mp_res);
        if (!mp_node) {
            rwlock_write_unlock(&namespace_rwlock);
            futex_up(&rootfs_futex);
            ipc_answer_0(rid, ENOMEM);
            return;
        }
       
        /*
         * Now we hold a reference to mp_node.
         * It will be dropped upon the corresponding VFS_UNMOUNT.
         * This prevents the mount point from being deleted.
         */
        rwlock_write_unlock(&namespace_rwlock);
    } else {
        /* We still don't have the root file system mounted. */
        if (str_cmp(mp, "/") == 0) {
            vfs_lookup_res_t mr_res;
            vfs_node_t *mr_node;
            ipcarg_t rindex;
            ipcarg_t rsize;
            ipcarg_t rlnkcnt;
           
            /*
             * For this simple, but important case,
             * we are almost done.
             */
           
            /* Tell the mountee that it is being mounted. */
            phone = vfs_grab_phone(fs_handle);
            rc = async_req_1_3(phone, VFS_MOUNTED,
                (ipcarg_t) dev_handle, &rindex, &rsize, &rlnkcnt);
            vfs_release_phone(phone);
           
            if (rc != EOK) {
                futex_up(&rootfs_futex);
                ipc_answer_0(rid, rc);
                return;
            }
           
            mr_res.triplet.fs_handle = fs_handle;
            mr_res.triplet.dev_handle = dev_handle;
            mr_res.triplet.index = (fs_index_t) rindex;
            mr_res.size = (size_t) rsize;
            mr_res.lnkcnt = (unsigned) rlnkcnt;
            mr_res.type = VFS_NODE_DIRECTORY;
           
            rootfs.fs_handle = fs_handle;
            rootfs.dev_handle = dev_handle;
            futex_up(&rootfs_futex);
           
            /* Add reference to the mounted root. */
            mr_node = vfs_node_get(&mr_res);
            assert(mr_node);
           
            ipc_answer_0(rid, rc);
            return;
        } else {
            /*
             * We can't resolve this without the root filesystem
             * being mounted first.
             */
            futex_up(&rootfs_futex);
            ipc_answer_0(rid, ENOENT);
            return;
        }
    }
    futex_up(&rootfs_futex);
   
    /*
     * At this point, we have all necessary pieces: file system and device
     * handles, and we know the mount point VFS node.
     */
   
    phone = vfs_grab_phone(mp_res.triplet.fs_handle);
    rc = async_req_4_0(phone, VFS_MOUNT,
        (ipcarg_t) mp_res.triplet.dev_handle,
        (ipcarg_t) mp_res.triplet.index,
        (ipcarg_t) fs_handle,
        (ipcarg_t) dev_handle);
    vfs_release_phone(phone);
   
    if (rc != EOK) {
        /* Mount failed, drop reference to mp_node. */
        if (mp_node)
            vfs_node_put(mp_node);
    }
   
    ipc_answer_0(rid, rc);
}
 
/** Process pending mount requests */
void vfs_process_pending_mount()
{
    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);
       
        fs_handle_t fs_handle = fs_name_to_handle(pr->fs_name, true);
        if (!fs_handle)
            continue;
       
        /* Acknowledge that we know fs_name. */
        ipc_answer_0(pr->callid, EOK);
       
        /* Do the mount */
        vfs_mount_internal(pr->rid, pr->dev_handle, fs_handle, pr->mp);
       
        free(pr->fs_name);
        free(pr->mp);
        list_remove(cur);
        free(pr);
        goto loop;
    }
}
 
void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
{
    /*
     * We expect the library to do the device-name to device-handle
     * translation for us, thus the device handle will arrive as ARG1
     * in the request.
     */
    dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
   
    /*
     * Mount flags are passed as ARG2.
     */
    unsigned int flags = (unsigned int) IPC_GET_ARG2(*request);
   
    /*
     * For now, don't make use of ARG3, but it can be used to
     * carry mount options in the future.
     */
   
    /* We want the client to send us the mount point. */
    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;
    }
   
    /* Check whether size is reasonable wrt. the mount point. */
    if ((size < 1) || (size > MAX_PATH_LEN)) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
   
    /* Allocate buffer for the mount point data being received. */
    char *mp = malloc(size + 1);
    if (!mp) {
        ipc_answer_0(callid, ENOMEM);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
   
    /* Deliver the mount point. */
    ipcarg_t retval = ipc_data_write_finalize(callid, mp, size);
    if (retval != EOK) {
        ipc_answer_0(rid, retval);
        free(mp);
        return;
    }
    mp[size] = '\0';
   
    /*
     * Now, we expect the client to send us data with the name of the file
     * system.
     */
    if (!ipc_data_write_receive(&callid, &size)) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        free(mp);
        return;
    }
   
    /*
     * Don't receive more than is necessary for storing a full file system
     * name.
     */
    if ((size < 1) || (size > FS_NAME_MAXLEN)) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        free(mp);
        return;
    }
   
    /*
     * Allocate buffer for file system name.
     */
    char *fs_name = (char *) malloc(size + 1);
    if (fs_name == NULL) {
        ipc_answer_0(callid, ENOMEM);
        ipc_answer_0(rid, ENOMEM);
        free(mp);
        return;
    }
   
    /* Deliver the file system name. */
    retval = ipc_data_write_finalize(callid, fs_name, size);
    if (retval != EOK) {
        ipc_answer_0(rid, retval);
        free(mp);
        free(fs_name);
        return;
    }
    fs_name[size] = '\0';
 
    /*
     * Wait for IPC_M_PING so that we can return an error if we don't know
     * fs_name.
     */
    ipc_call_t data;
    callid = async_get_call(&data);
    if (IPC_GET_METHOD(data) != IPC_M_PING) {
        ipc_answer_0(callid, ENOTSUP);
        ipc_answer_0(rid, ENOTSUP);
        free(mp);
        free(fs_name);
        return;
    }
 
    /*
     * Check if we know a file system with the same name as is in fs_name.
     * This will also give us its file system handle.
     */
    fs_handle_t fs_handle = fs_name_to_handle(fs_name, true);
    if (!fs_handle) {
        if (flags & IPC_FLAG_BLOCKING) {
            pending_req_t *pr;
 
            /* Blocking mount, add to pending list */
            pr = (pending_req_t *) malloc(sizeof(pending_req_t));
            if (!pr) {
                ipc_answer_0(callid, ENOMEM);
                ipc_answer_0(rid, ENOMEM);
                free(mp);
                free(fs_name);
                return;
            }
           
            pr->fs_name = fs_name;
            pr->mp = mp;
            pr->callid = callid;
            pr->rid = rid;
            pr->dev_handle = dev_handle;
            link_initialize(&pr->link);
            list_append(&pr->link, &pending_req);
            return;
        }
       
        ipc_answer_0(callid, ENOENT);
        ipc_answer_0(rid, ENOENT);
        free(mp);
        free(fs_name);
        return;
    }
   
    /* Acknowledge that we know fs_name. */
    ipc_answer_0(callid, EOK);
   
    /* Do the mount */
    vfs_mount_internal(rid, dev_handle, fs_handle, mp);
    free(mp);
    free(fs_name);
}
 
void vfs_open(ipc_callid_t rid, ipc_call_t *request)
{
    if (!vfs_files_init()) {
        ipc_answer_0(rid, ENOMEM);
        return;
    }
 
    /*
     * The POSIX interface is open(path, oflag, mode).
     * We can receive oflags and mode along with the VFS_OPEN call; the path
     * will need to arrive in another call.
     *
     * We also receive one private, non-POSIX set of flags called lflag
     * used to pass information to vfs_lookup_internal().
     */
    int lflag = IPC_GET_ARG1(*request);
    int oflag = IPC_GET_ARG2(*request);
    int mode = IPC_GET_ARG3(*request);
    size_t len;
 
    /*
     * Make sure that we are called with exactly one of L_FILE and
     * L_DIRECTORY.
     */
    if ((lflag & (L_FILE | L_DIRECTORY)) == 0 ||
        (lflag & (L_FILE | L_DIRECTORY)) == (L_FILE | L_DIRECTORY)) {
        ipc_answer_0(rid, EINVAL);
        return;
    }
 
    if (oflag & O_CREAT)
        lflag |= L_CREATE;
    if (oflag & O_EXCL)
        lflag |= L_EXCLUSIVE;
 
    ipc_callid_t callid;
 
    if (!ipc_data_write_receive(&callid, &len)) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
    char *path = malloc(len + 1);
    if (!path) {
        ipc_answer_0(callid, ENOMEM);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    int rc;
    if ((rc = ipc_data_write_finalize(callid, path, len))) {
        ipc_answer_0(rid, rc);
        free(path);
        return;
    }
    path[len] = '\0';
   
    /*
     * Avoid the race condition in which the file can be deleted before we
     * find/create-and-lock the VFS node corresponding to the looked-up
     * triplet.
     */
    if (lflag & L_CREATE)
        rwlock_write_lock(&namespace_rwlock);
    else
        rwlock_read_lock(&namespace_rwlock);
 
    /* The path is now populated and we can call vfs_lookup_internal(). */
    vfs_lookup_res_t lr;
    rc = vfs_lookup_internal(path, lflag, &lr, NULL);
    if (rc) {
        if (lflag & L_CREATE)
            rwlock_write_unlock(&namespace_rwlock);
        else
            rwlock_read_unlock(&namespace_rwlock);
        ipc_answer_0(rid, rc);
        free(path);
        return;
    }
 
    /* Path is no longer needed. */
    free(path);
 
    vfs_node_t *node = vfs_node_get(&lr);
    if (lflag & L_CREATE)
        rwlock_write_unlock(&namespace_rwlock);
    else
        rwlock_read_unlock(&namespace_rwlock);
 
    /* Truncate the file if requested and if necessary. */
    if (oflag & O_TRUNC) {
        rwlock_write_lock(&node->contents_rwlock);
        if (node->size) {
            rc = vfs_truncate_internal(node->fs_handle,
                node->dev_handle, node->index, 0);
            if (rc) {
                rwlock_write_unlock(&node->contents_rwlock);
                vfs_node_put(node);
                ipc_answer_0(rid, rc);
                return;
            }
            node->size = 0;
        }
        rwlock_write_unlock(&node->contents_rwlock);
    }
 
    /*
     * Get ourselves a file descriptor and the corresponding vfs_file_t
     * structure.
     */
    int fd = vfs_fd_alloc();
    if (fd < 0) {
        vfs_node_put(node);
        ipc_answer_0(rid, fd);
        return;
    }
    vfs_file_t *file = vfs_file_get(fd);
    file->node = node;
    if (oflag & O_APPEND)
        file->append = true;
 
    /*
     * The following increase in reference count is for the fact that the
     * file is being opened and that a file structure is pointing to it.
     * It is necessary so that the file will not disappear when
     * vfs_node_put() is called. The reference will be dropped by the
     * respective VFS_CLOSE.
     */
    vfs_node_addref(node);
    vfs_node_put(node);
 
    /* Success! Return the new file descriptor to the client. */
    ipc_answer_1(rid, EOK, fd);
}
 
void vfs_close(ipc_callid_t rid, ipc_call_t *request)
{
    int fd = IPC_GET_ARG1(*request);
    int rc = vfs_fd_free(fd);
    ipc_answer_0(rid, rc);
}
 
static void vfs_rdwr(ipc_callid_t rid, ipc_call_t *request, bool read)
{
 
    /*
     * The following code strongly depends on the fact that the files data
     * structure can be only accessed by a single fibril and all file
     * operations are serialized (i.e. the reads and writes cannot
     * interleave and a file cannot be closed while it is being read).
     *
     * Additional synchronization needs to be added once the table of
     * open files supports parallel access!
     */
 
    int fd = IPC_GET_ARG1(*request);
   
    /* Lookup the file structure corresponding to the file descriptor. */
    vfs_file_t *file = vfs_file_get(fd);
    if (!file) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
   
    /*
     * Now we need to receive a call with client's
     * IPC_M_DATA_READ/IPC_M_DATA_WRITE request.
     */
    ipc_callid_t callid;
    int res;
    if (read)
        res = ipc_data_read_receive(&callid, NULL);
    else
        res = ipc_data_write_receive(&callid, NULL);
    if (!res) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
   
    /*
     * Lock the open file structure so that no other thread can manipulate
     * the same open file at a time.
     */
    futex_down(&file->lock);
 
    /*
     * Lock the file's node so that no other client can read/write to it at
     * the same time.
     */
    if (read)
        rwlock_read_lock(&file->node->contents_rwlock);
    else
        rwlock_write_lock(&file->node->contents_rwlock);
 
    if (file->node->type == VFS_NODE_DIRECTORY) {
        /*
         * Make sure that no one is modifying the namespace
         * while we are in readdir().
         */
        assert(read);
        rwlock_read_lock(&namespace_rwlock);
    }
   
    int fs_phone = vfs_grab_phone(file->node->fs_handle);  
   
    /* Make a VFS_READ/VFS_WRITE request at the destination FS server. */
    aid_t msg;
    ipc_call_t answer;
    if (!read && file->append)
        file->pos = file->node->size;
    msg = async_send_3(fs_phone, IPC_GET_METHOD(*request),
        file->node->dev_handle, file->node->index, file->pos, &answer);
   
    /*
     * Forward the IPC_M_DATA_READ/IPC_M_DATA_WRITE request to the
     * destination FS server. The call will be routed as if sent by
     * ourselves. Note that call arguments are immutable in this case so we
     * don't have to bother.
     */
    ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
   
    vfs_release_phone(fs_phone);
   
    /* Wait for reply from the FS server. */
    ipcarg_t rc;
    async_wait_for(msg, &rc);
    size_t bytes = IPC_GET_ARG1(answer);
 
    if (file->node->type == VFS_NODE_DIRECTORY)
        rwlock_read_unlock(&namespace_rwlock);
   
    /* Unlock the VFS node. */
    if (read)
        rwlock_read_unlock(&file->node->contents_rwlock);
    else {
        /* Update the cached version of node's size. */
        if (rc == EOK)
            file->node->size = IPC_GET_ARG2(answer);
        rwlock_write_unlock(&file->node->contents_rwlock);
    }
   
    /* Update the position pointer and unlock the open file. */
    if (rc == EOK)
        file->pos += bytes;
    futex_up(&file->lock);
   
    /*
     * FS server's reply is the final result of the whole operation we
     * return to the client.
     */
    ipc_answer_1(rid, rc, bytes);
}
 
void vfs_read(ipc_callid_t rid, ipc_call_t *request)
{
    vfs_rdwr(rid, request, true);
}
 
void vfs_write(ipc_callid_t rid, ipc_call_t *request)
{
    vfs_rdwr(rid, request, false);
}
 
void vfs_seek(ipc_callid_t rid, ipc_call_t *request)
{
    int fd = (int) IPC_GET_ARG1(*request);
    off_t off = (off_t) IPC_GET_ARG2(*request);
    int whence = (int) IPC_GET_ARG3(*request);
 
 
    /* Lookup the file structure corresponding to the file descriptor. */
    vfs_file_t *file = vfs_file_get(fd);
    if (!file) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
 
    off_t newpos;
    futex_down(&file->lock);
    if (whence == SEEK_SET) {
        file->pos = off;
        futex_up(&file->lock);
        ipc_answer_1(rid, EOK, off);
        return;
    }
    if (whence == SEEK_CUR) {
        if (file->pos + off < file->pos) {
            futex_up(&file->lock);
            ipc_answer_0(rid, EOVERFLOW);
            return;
        }
        file->pos += off;
        newpos = file->pos;
        futex_up(&file->lock);
        ipc_answer_1(rid, EOK, newpos);
        return;
    }
    if (whence == SEEK_END) {
        rwlock_read_lock(&file->node->contents_rwlock);
        size_t size = file->node->size;
        rwlock_read_unlock(&file->node->contents_rwlock);
        if (size + off < size) {
            futex_up(&file->lock);
            ipc_answer_0(rid, EOVERFLOW);
            return;
        }
        newpos = size + off;
        futex_up(&file->lock);
        ipc_answer_1(rid, EOK, newpos);
        return;
    }
    futex_up(&file->lock);
    ipc_answer_0(rid, EINVAL);
}
 
int
vfs_truncate_internal(fs_handle_t fs_handle, dev_handle_t dev_handle,
    fs_index_t index, size_t size)
{
    ipcarg_t rc;
    int fs_phone;
   
    fs_phone = vfs_grab_phone(fs_handle);
    rc = async_req_3_0(fs_phone, VFS_TRUNCATE, (ipcarg_t)dev_handle,
        (ipcarg_t)index, (ipcarg_t)size);
    vfs_release_phone(fs_phone);
    return (int)rc;
}
 
void vfs_truncate(ipc_callid_t rid, ipc_call_t *request)
{
    int fd = IPC_GET_ARG1(*request);
    size_t size = IPC_GET_ARG2(*request);
    int rc;
 
    vfs_file_t *file = vfs_file_get(fd);
    if (!file) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
    futex_down(&file->lock);
 
    rwlock_write_lock(&file->node->contents_rwlock);
    rc = vfs_truncate_internal(file->node->fs_handle,
        file->node->dev_handle, file->node->index, size);
    if (rc == EOK)
        file->node->size = size;
    rwlock_write_unlock(&file->node->contents_rwlock);
 
    futex_up(&file->lock);
    ipc_answer_0(rid, (ipcarg_t)rc);
}
 
void vfs_mkdir(ipc_callid_t rid, ipc_call_t *request)
{
    int mode = IPC_GET_ARG1(*request);
 
    size_t len;
    ipc_callid_t callid;
 
    if (!ipc_data_write_receive(&callid, &len)) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
    char *path = malloc(len + 1);
    if (!path) {
        ipc_answer_0(callid, ENOMEM);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    int rc;
    if ((rc = ipc_data_write_finalize(callid, path, len))) {
        ipc_answer_0(rid, rc);
        free(path);
        return;
    }
    path[len] = '\0';
   
    rwlock_write_lock(&namespace_rwlock);
    int lflag = L_DIRECTORY | L_CREATE | L_EXCLUSIVE;
    rc = vfs_lookup_internal(path, lflag, NULL, NULL);
    rwlock_write_unlock(&namespace_rwlock);
    free(path);
    ipc_answer_0(rid, rc);
}
 
void vfs_unlink(ipc_callid_t rid, ipc_call_t *request)
{
    int lflag = IPC_GET_ARG1(*request);
 
    size_t len;
    ipc_callid_t callid;
 
    if (!ipc_data_write_receive(&callid, &len)) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
    char *path = malloc(len + 1);
    if (!path) {
        ipc_answer_0(callid, ENOMEM);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    int rc;
    if ((rc = ipc_data_write_finalize(callid, path, len))) {
        ipc_answer_0(rid, rc);
        free(path);
        return;
    }
    path[len] = '\0';
   
    rwlock_write_lock(&namespace_rwlock);
    lflag &= L_DIRECTORY;   /* sanitize lflag */
    vfs_lookup_res_t lr;
    rc = vfs_lookup_internal(path, lflag | L_UNLINK, &lr, NULL);
    free(path);
    if (rc != EOK) {
        rwlock_write_unlock(&namespace_rwlock);
        ipc_answer_0(rid, rc);
        return;
    }
 
    /*
     * The name has already been unlinked by vfs_lookup_internal().
     * We have to get and put the VFS node to ensure that it is
     * VFS_DESTROY'ed after the last reference to it is dropped.
     */
    vfs_node_t *node = vfs_node_get(&lr);
    futex_down(&nodes_futex);
    node->lnkcnt--;
    futex_up(&nodes_futex);
    rwlock_write_unlock(&namespace_rwlock);
    vfs_node_put(node);
    ipc_answer_0(rid, EOK);
}
 
void vfs_rename(ipc_callid_t rid, ipc_call_t *request)
{
    size_t olen, nlen;
    ipc_callid_t callid;
    int rc;
 
    /* Retrieve the old path. */
    if (!ipc_data_write_receive(&callid, &olen)) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
    char *old = malloc(olen + 1);
    if (!old) {
        ipc_answer_0(callid, ENOMEM);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    if ((rc = ipc_data_write_finalize(callid, old, olen))) {
        ipc_answer_0(rid, rc);
        free(old);
        return;
    }
    old[olen] = '\0';
   
    /* Retrieve the new path. */
    if (!ipc_data_write_receive(&callid, &nlen)) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        free(old);
        return;
    }
    char *new = malloc(nlen + 1);
    if (!new) {
        ipc_answer_0(callid, ENOMEM);
        ipc_answer_0(rid, ENOMEM);
        free(old);
        return;
    }
    if ((rc = ipc_data_write_finalize(callid, new, nlen))) {
        ipc_answer_0(rid, rc);
        free(old);
        free(new);
        return;
    }
    new[nlen] = '\0';
 
    char *oldc = canonify(old, &olen);
    char *newc = canonify(new, &nlen);
    if (!oldc || !newc) {
        ipc_answer_0(rid, EINVAL);
        free(old);
        free(new);
        return;
    }
    oldc[olen] = '\0';
    newc[nlen] = '\0';
    if (!str_lcmp(newc, oldc, str_length(oldc))) {
        /* oldc is a prefix of newc */
        ipc_answer_0(rid, EINVAL);
        free(old);
        free(new);
        return;
    }
   
    vfs_lookup_res_t old_lr;
    vfs_lookup_res_t new_lr;
    vfs_lookup_res_t new_par_lr;
    rwlock_write_lock(&namespace_rwlock);
    /* Lookup the node belonging to the old file name. */
    rc = vfs_lookup_internal(oldc, L_NONE, &old_lr, NULL);
    if (rc != EOK) {
        rwlock_write_unlock(&namespace_rwlock);
        ipc_answer_0(rid, rc);
        free(old);
        free(new);
        return;
    }
    vfs_node_t *old_node = vfs_node_get(&old_lr);
    if (!old_node) {
        rwlock_write_unlock(&namespace_rwlock);
        ipc_answer_0(rid, ENOMEM);
        free(old);
        free(new);
        return;
    }
    /* Lookup parent of the new file name. */
    rc = vfs_lookup_internal(newc, L_PARENT, &new_par_lr, NULL);
    if (rc != EOK) {
        rwlock_write_unlock(&namespace_rwlock);
        ipc_answer_0(rid, rc);
        free(old);
        free(new);
        return;
    }
    /* Check whether linking to the same file system instance. */
    if ((old_node->fs_handle != new_par_lr.triplet.fs_handle) ||
        (old_node->dev_handle != new_par_lr.triplet.dev_handle)) {
        rwlock_write_unlock(&namespace_rwlock);
        ipc_answer_0(rid, EXDEV);   /* different file systems */
        free(old);
        free(new);
        return;
    }
    /* Destroy the old link for the new name. */
    vfs_node_t *new_node = NULL;
    rc = vfs_lookup_internal(newc, L_UNLINK, &new_lr, NULL);
    switch (rc) {
    case ENOENT:
        /* simply not in our way */
        break;
    case EOK:
        new_node = vfs_node_get(&new_lr);
        if (!new_node) {
            rwlock_write_unlock(&namespace_rwlock);
            ipc_answer_0(rid, ENOMEM);
            free(old);
            free(new);
            return;
        }
        futex_down(&nodes_futex);
        new_node->lnkcnt--;
        futex_up(&nodes_futex);
        break;
    default:
        rwlock_write_unlock(&namespace_rwlock);
        ipc_answer_0(rid, ENOTEMPTY);
        free(old);
        free(new);
        return;
    }
    /* Create the new link for the new name. */
    rc = vfs_lookup_internal(newc, L_LINK, NULL, NULL, old_node->index);
    if (rc != EOK) {
        rwlock_write_unlock(&namespace_rwlock);
        if (new_node)
            vfs_node_put(new_node);
        ipc_answer_0(rid, rc);
        free(old);
        free(new);
        return;
    }
    futex_down(&nodes_futex);
    old_node->lnkcnt++;
    futex_up(&nodes_futex);
    /* Destroy the link for the old name. */
    rc = vfs_lookup_internal(oldc, L_UNLINK, NULL, NULL);
    if (rc != EOK) {
        rwlock_write_unlock(&namespace_rwlock);
        vfs_node_put(old_node);
        if (new_node)
            vfs_node_put(new_node);
        ipc_answer_0(rid, rc);
        free(old);
        free(new);
        return;
    }
    futex_down(&nodes_futex);
    old_node->lnkcnt--;
    futex_up(&nodes_futex);
    rwlock_write_unlock(&namespace_rwlock);
    vfs_node_put(old_node);
    if (new_node)
        vfs_node_put(new_node);
    free(old);
    free(new);
    ipc_answer_0(rid, EOK);
}
 
/**
 * @}
 */
 

Rev 4301	Rev 4302
1	/*	1	/*
2	* Copyright (c) 2008 Jakub Jermar	2	* Copyright (c) 2008 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/** @addtogroup fs	29	/** @addtogroup fs
30	* @{	30	* @{
31	*/	31	*/
32		32
33	/**	33	/**
34	* @file vfs_ops.c	34	* @file vfs_ops.c
35	* @brief Operations that VFS offers to its clients.	35	* @brief Operations that VFS offers to its clients.
36	*/	36	*/
37		37
38	#include "vfs.h"	38	#include "vfs.h"
39	#include <ipc/ipc.h>	39	#include <ipc/ipc.h>
40	#include <async.h>	40	#include <async.h>
41	#include <errno.h>	41	#include <errno.h>
42	#include <stdio.h>	42	#include <stdio.h>
43	#include <stdlib.h>	43	#include <stdlib.h>
44	#include <string.h>	44	#include <string.h>
45	#include <bool.h>	45	#include <bool.h>
46	#include <futex.h>	46	#include <futex.h>
47	#include <rwlock.h>	47	#include <rwlock.h>
48	#include <libadt/list.h>	48	#include <libadt/list.h>
49	#include <unistd.h>	49	#include <unistd.h>
50	#include <ctype.h>	50	#include <ctype.h>
51	#include <fcntl.h>	51	#include <fcntl.h>
52	#include <assert.h>	52	#include <assert.h>
53	#include <vfs/canonify.h>	53	#include <vfs/canonify.h>
54		54
55	/* Forward declarations of static functions. */	55	/* Forward declarations of static functions. */
56	static int vfs_truncate_internal(fs_handle_t, dev_handle_t, fs_index_t, size_t);	56	static int vfs_truncate_internal(fs_handle_t, dev_handle_t, fs_index_t, size_t);
57		57
58	/** Pending mount structure. */	58	/** Pending mount structure. */
59	typedef struct {	59	typedef struct {
60	link_t link;	60	link_t link;
61	char fs_name; /< File system name /	61	char fs_name; /< File system name /
62	char mp; /< Mount point /	62	char mp; /< Mount point /
63	ipc_callid_t callid; /*< Call ID waiting for the mount /	63	ipc_callid_t callid; /*< Call ID waiting for the mount /
64	ipc_callid_t rid; /*< Request ID /	64	ipc_callid_t rid; /*< Request ID /
65	dev_handle_t dev_handle; /*< Device handle /	65	dev_handle_t dev_handle; /*< Device handle /
66	} pending_req_t;	66	} pending_req_t;
67		67
68	LIST_INITIALIZE(pending_req);	68	LIST_INITIALIZE(pending_req);
69		69
70	/**	70	/**
71	* This rwlock prevents the race between a triplet-to-VFS-node resolution and a	71	* This rwlock prevents the race between a triplet-to-VFS-node resolution and a
72	* concurrent VFS operation which modifies the file system namespace.	72	* concurrent VFS operation which modifies the file system namespace.
73	*/	73	*/
74	RWLOCK_INITIALIZE(namespace_rwlock);	74	RWLOCK_INITIALIZE(namespace_rwlock);
75		75
76	futex_t rootfs_futex = FUTEX_INITIALIZER;	76	futex_t rootfs_futex = FUTEX_INITIALIZER;
77	vfs_pair_t rootfs = {	77	vfs_pair_t rootfs = {
78	.fs_handle = 0,	78	.fs_handle = 0,
79	.dev_handle = 0	79	.dev_handle = 0
80	};	80	};
81		81
82	static void vfs_mount_internal(ipc_callid_t rid, dev_handle_t dev_handle,	82	static void vfs_mount_internal(ipc_callid_t rid, dev_handle_t dev_handle,
83	fs_handle_t fs_handle, char *mp)	83	fs_handle_t fs_handle, char *mp)
84	{	84	{
85	/* Resolve the path to the mountpoint. */	85	/* Resolve the path to the mountpoint. */
86	vfs_lookup_res_t mp_res;	86	vfs_lookup_res_t mp_res;
87	vfs_node_t *mp_node = NULL;	87	vfs_node_t *mp_node = NULL;
88	int rc;	88	int rc;
89	int phone;	89	int phone;
90	futex_down(&rootfs_futex);	90	futex_down(&rootfs_futex);
91	if (rootfs.fs_handle) {	91	if (rootfs.fs_handle) {
92	/* We already have the root FS. */	92	/* We already have the root FS. */
93	rwlock_write_lock(&namespace_rwlock);	93	rwlock_write_lock(&namespace_rwlock);
94	if (str_cmp(mp, "/") == 0) {	94	if (str_cmp(mp, "/") == 0) {
95	/* Trying to mount root FS over root FS */	95	/* Trying to mount root FS over root FS */
96	rwlock_write_unlock(&namespace_rwlock);	96	rwlock_write_unlock(&namespace_rwlock);
97	futex_up(&rootfs_futex);	97	futex_up(&rootfs_futex);
98	ipc_answer_0(rid, EBUSY);	98	ipc_answer_0(rid, EBUSY);
99	return;	99	return;
100	}	100	}
101		101
102	rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);	102	rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);
103	if (rc != EOK) {	103	if (rc != EOK) {
104	/* The lookup failed for some reason. */	104	/* The lookup failed for some reason. */
105	rwlock_write_unlock(&namespace_rwlock);	105	rwlock_write_unlock(&namespace_rwlock);
106	futex_up(&rootfs_futex);	106	futex_up(&rootfs_futex);
107	ipc_answer_0(rid, rc);	107	ipc_answer_0(rid, rc);
108	return;	108	return;
109	}	109	}
110		110
111	mp_node = vfs_node_get(&mp_res);	111	mp_node = vfs_node_get(&mp_res);
112	if (!mp_node) {	112	if (!mp_node) {
113	rwlock_write_unlock(&namespace_rwlock);	113	rwlock_write_unlock(&namespace_rwlock);
114	futex_up(&rootfs_futex);	114	futex_up(&rootfs_futex);
115	ipc_answer_0(rid, ENOMEM);	115	ipc_answer_0(rid, ENOMEM);
116	return;	116	return;
117	}	117	}
118		118
119	/*	119	/*
120	* Now we hold a reference to mp_node.	120	* Now we hold a reference to mp_node.
121	* It will be dropped upon the corresponding VFS_UNMOUNT.	121	* It will be dropped upon the corresponding VFS_UNMOUNT.
122	* This prevents the mount point from being deleted.	122	* This prevents the mount point from being deleted.
123	*/	123	*/
124	rwlock_write_unlock(&namespace_rwlock);	124	rwlock_write_unlock(&namespace_rwlock);
125	} else {	125	} else {
126	/* We still don't have the root file system mounted. */	126	/* We still don't have the root file system mounted. */
127	if (str_cmp(mp, "/") == 0) {	127	if (str_cmp(mp, "/") == 0) {
128	vfs_lookup_res_t mr_res;	128	vfs_lookup_res_t mr_res;
129	vfs_node_t *mr_node;	129	vfs_node_t *mr_node;
130	ipcarg_t rindex;	130	ipcarg_t rindex;
131	ipcarg_t rsize;	131	ipcarg_t rsize;
132	ipcarg_t rlnkcnt;	132	ipcarg_t rlnkcnt;
133		133
134	/*	134	/*
135	* For this simple, but important case,	135	* For this simple, but important case,
136	* we are almost done.	136	* we are almost done.
137	*/	137	*/
138		138
139	/* Tell the mountee that it is being mounted. */	139	/* Tell the mountee that it is being mounted. */
140	phone = vfs_grab_phone(fs_handle);	140	phone = vfs_grab_phone(fs_handle);
141	rc = async_req_1_3(phone, VFS_MOUNTED,	141	rc = async_req_1_3(phone, VFS_MOUNTED,
142	(ipcarg_t) dev_handle, &rindex, &rsize, &rlnkcnt);	142	(ipcarg_t) dev_handle, &rindex, &rsize, &rlnkcnt);
143	vfs_release_phone(phone);	143	vfs_release_phone(phone);
144		144
145	if (rc != EOK) {	145	if (rc != EOK) {
146	futex_up(&rootfs_futex);	146	futex_up(&rootfs_futex);
147	ipc_answer_0(rid, rc);	147	ipc_answer_0(rid, rc);
148	return;	148	return;
149	}	149	}
150		150
151	mr_res.triplet.fs_handle = fs_handle;	151	mr_res.triplet.fs_handle = fs_handle;
152	mr_res.triplet.dev_handle = dev_handle;	152	mr_res.triplet.dev_handle = dev_handle;
153	mr_res.triplet.index = (fs_index_t) rindex;	153	mr_res.triplet.index = (fs_index_t) rindex;
154	mr_res.size = (size_t) rsize;	154	mr_res.size = (size_t) rsize;
155	mr_res.lnkcnt = (unsigned) rlnkcnt;	155	mr_res.lnkcnt = (unsigned) rlnkcnt;
156	mr_res.type = VFS_NODE_DIRECTORY;	156	mr_res.type = VFS_NODE_DIRECTORY;
157		157
158	rootfs.fs_handle = fs_handle;	158	rootfs.fs_handle = fs_handle;
159	rootfs.dev_handle = dev_handle;	159	rootfs.dev_handle = dev_handle;
160	futex_up(&rootfs_futex);	160	futex_up(&rootfs_futex);
161		161
162	/* Add reference to the mounted root. */	162	/* Add reference to the mounted root. */
163	mr_node = vfs_node_get(&mr_res);	163	mr_node = vfs_node_get(&mr_res);
164	assert(mr_node);	164	assert(mr_node);
165		165
166	ipc_answer_0(rid, rc);	166	ipc_answer_0(rid, rc);
167	return;	167	return;
168	} else {	168	} else {
169	/*	169	/*
170	* We can't resolve this without the root filesystem	170	* We can't resolve this without the root filesystem
171	* being mounted first.	171	* being mounted first.
172	*/	172	*/
173	futex_up(&rootfs_futex);	173	futex_up(&rootfs_futex);
174	ipc_answer_0(rid, ENOENT);	174	ipc_answer_0(rid, ENOENT);
175	return;	175	return;
176	}	176	}
177	}	177	}
178	futex_up(&rootfs_futex);	178	futex_up(&rootfs_futex);
179		179
180	/*	180	/*
181	* At this point, we have all necessary pieces: file system and device	181	* At this point, we have all necessary pieces: file system and device
182	* handles, and we know the mount point VFS node.	182	* handles, and we know the mount point VFS node.
183	*/	183	*/
184		184
185	phone = vfs_grab_phone(mp_res.triplet.fs_handle);	185	phone = vfs_grab_phone(mp_res.triplet.fs_handle);
186	rc = async_req_4_0(phone, VFS_MOUNT,	186	rc = async_req_4_0(phone, VFS_MOUNT,
187	(ipcarg_t) mp_res.triplet.dev_handle,	187	(ipcarg_t) mp_res.triplet.dev_handle,
188	(ipcarg_t) mp_res.triplet.index,	188	(ipcarg_t) mp_res.triplet.index,
189	(ipcarg_t) fs_handle,	189	(ipcarg_t) fs_handle,
190	(ipcarg_t) dev_handle);	190	(ipcarg_t) dev_handle);
191	vfs_release_phone(phone);	191	vfs_release_phone(phone);
192		192
193	if (rc != EOK) {	193	if (rc != EOK) {
194	/* Mount failed, drop reference to mp_node. */	194	/* Mount failed, drop reference to mp_node. */
195	if (mp_node)	195	if (mp_node)
196	vfs_node_put(mp_node);	196	vfs_node_put(mp_node);
197	}	197	}
198		198
199	ipc_answer_0(rid, rc);	199	ipc_answer_0(rid, rc);
200	}	200	}
201		201
202	/** Process pending mount requests */	202	/** Process pending mount requests */
203	void vfs_process_pending_mount()	203	void vfs_process_pending_mount()
204	{	204	{
205	link_t *cur;	205	link_t *cur;
206		206
207	loop:	207	loop:
208	for (cur = pending_req.next; cur != &pending_req; cur = cur->next) {	208	for (cur = pending_req.next; cur != &pending_req; cur = cur->next) {
209	pending_req_t *pr = list_get_instance(cur, pending_req_t, link);	209	pending_req_t *pr = list_get_instance(cur, pending_req_t, link);
210		210
211	fs_handle_t fs_handle = fs_name_to_handle(pr->fs_name, true);	211	fs_handle_t fs_handle = fs_name_to_handle(pr->fs_name, true);
212	if (!fs_handle)	212	if (!fs_handle)
213	continue;	213	continue;
214		214
215	/* Acknowledge that we know fs_name. */	215	/* Acknowledge that we know fs_name. */
216	ipc_answer_0(pr->callid, EOK);	216	ipc_answer_0(pr->callid, EOK);
217		217
218	/* Do the mount */	218	/* Do the mount */
219	vfs_mount_internal(pr->rid, pr->dev_handle, fs_handle, pr->mp);	219	vfs_mount_internal(pr->rid, pr->dev_handle, fs_handle, pr->mp);
220		220
221	free(pr->fs_name);	221	free(pr->fs_name);
222	free(pr->mp);	222	free(pr->mp);
223	list_remove(cur);	223	list_remove(cur);
224	free(pr);	224	free(pr);
225	goto loop;	225	goto loop;
226	}	226	}
227	}	227	}
228		228
229	void vfs_mount(ipc_callid_t rid, ipc_call_t *request)	229	void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
230	{	230	{
231	/*	231	/*
232	* We expect the library to do the device-name to device-handle	232	* We expect the library to do the device-name to device-handle
233	* translation for us, thus the device handle will arrive as ARG1	233	* translation for us, thus the device handle will arrive as ARG1
234	* in the request.	234	* in the request.
235	*/	235	*/
236	dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);	236	dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
237		237
238	/*	238	/*
239	* Mount flags are passed as ARG2.	239	* Mount flags are passed as ARG2.
240	*/	240	*/
241	unsigned int flags = (unsigned int) IPC_GET_ARG2(*request);	241	unsigned int flags = (unsigned int) IPC_GET_ARG2(*request);
242		242
243	/*	243	/*
244	* For now, don't make use of ARG3, but it can be used to	244	* For now, don't make use of ARG3, but it can be used to
245	* carry mount options in the future.	245	* carry mount options in the future.
246	*/	246	*/
247		247
248	/* We want the client to send us the mount point. */	248	/* We want the client to send us the mount point. */
249	ipc_callid_t callid;	249	ipc_callid_t callid;
250	size_t size;	250	size_t size;
251	if (!ipc_data_write_receive(&callid, &size)) {	251	if (!ipc_data_write_receive(&callid, &size)) {
252	ipc_answer_0(callid, EINVAL);	252	ipc_answer_0(callid, EINVAL);
253	ipc_answer_0(rid, EINVAL);	253	ipc_answer_0(rid, EINVAL);
254	return;	254	return;
255	}	255	}
256		256
257	/* Check whether size is reasonable wrt. the mount point. */	257	/* Check whether size is reasonable wrt. the mount point. */
258	if ((size < 1) \|\| (size > MAX_PATH_LEN)) {	258	if ((size < 1) \|\| (size > MAX_PATH_LEN)) {
259	ipc_answer_0(callid, EINVAL);	259	ipc_answer_0(callid, EINVAL);
260	ipc_answer_0(rid, EINVAL);	260	ipc_answer_0(rid, EINVAL);
261	return;	261	return;
262	}	262	}
263		263
264	/* Allocate buffer for the mount point data being received. */	264	/* Allocate buffer for the mount point data being received. */
265	char *mp = malloc(size + 1);	265	char *mp = malloc(size + 1);
266	if (!mp) {	266	if (!mp) {
267	ipc_answer_0(callid, ENOMEM);	267	ipc_answer_0(callid, ENOMEM);
268	ipc_answer_0(rid, ENOMEM);	268	ipc_answer_0(rid, ENOMEM);
269	return;	269	return;
270	}	270	}
271		271
272	/* Deliver the mount point. */	272	/* Deliver the mount point. */
273	ipcarg_t retval = ipc_data_write_finalize(callid, mp, size);	273	ipcarg_t retval = ipc_data_write_finalize(callid, mp, size);
274	if (retval != EOK) {	274	if (retval != EOK) {
275	ipc_answer_0(rid, retval);	275	ipc_answer_0(rid, retval);
276	free(mp);	276	free(mp);
277	return;	277	return;
278	}	278	}
279	mp[size] = '\0';	279	mp[size] = '\0';
280		280
281	/*	281	/*
282	* Now, we expect the client to send us data with the name of the file	282	* Now, we expect the client to send us data with the name of the file
283	* system.	283	* system.
284	*/	284	*/
285	if (!ipc_data_write_receive(&callid, &size)) {	285	if (!ipc_data_write_receive(&callid, &size)) {
286	ipc_answer_0(callid, EINVAL);	286	ipc_answer_0(callid, EINVAL);
287	ipc_answer_0(rid, EINVAL);	287	ipc_answer_0(rid, EINVAL);
288	free(mp);	288	free(mp);
289	return;	289	return;
290	}	290	}
291		291
292	/*	292	/*
293	* Don't receive more than is necessary for storing a full file system	293	* Don't receive more than is necessary for storing a full file system
294	* name.	294	* name.
295	*/	295	*/
296	if ((size < 1) \|\| (size > FS_NAME_MAXLEN)) {	296	if ((size < 1) \|\| (size > FS_NAME_MAXLEN)) {
297	ipc_answer_0(callid, EINVAL);	297	ipc_answer_0(callid, EINVAL);
298	ipc_answer_0(rid, EINVAL);	298	ipc_answer_0(rid, EINVAL);
299	free(mp);	299	free(mp);
300	return;	300	return;
301	}	301	}
302		302
303	/*	303	/*
304	* Allocate buffer for file system name.	304	* Allocate buffer for file system name.
305	*/	305	*/
306	char fs_name = (char ) malloc(size + 1);	306	char fs_name = (char ) malloc(size + 1);
307	if (fs_name == NULL) {	307	if (fs_name == NULL) {
308	ipc_answer_0(callid, ENOMEM);	308	ipc_answer_0(callid, ENOMEM);
309	ipc_answer_0(rid, ENOMEM);	309	ipc_answer_0(rid, ENOMEM);
310	free(mp);	310	free(mp);
311	return;	311	return;
312	}	312	}
313		313
314	/* Deliver the file system name. */	314	/* Deliver the file system name. */
315	retval = ipc_data_write_finalize(callid, fs_name, size);	315	retval = ipc_data_write_finalize(callid, fs_name, size);
316	if (retval != EOK) {	316	if (retval != EOK) {
317	ipc_answer_0(rid, retval);	317	ipc_answer_0(rid, retval);
318	free(mp);	318	free(mp);
319	free(fs_name);	319	free(fs_name);
320	return;	320	return;
321	}	321	}
322	fs_name[size] = '\0';	322	fs_name[size] = '\0';
-		323
-		324	/*
-		325	* Wait for IPC_M_PING so that we can return an error if we don't know
-		326	* fs_name.
-		327	*/
-		328	ipc_call_t data;
-		329	callid = async_get_call(&data);
-		330	if (IPC_GET_METHOD(data) != IPC_M_PING) {
-		331	ipc_answer_0(callid, ENOTSUP);
-		332	ipc_answer_0(rid, ENOTSUP);
-		333	free(mp);
-		334	free(fs_name);
-		335	return;
323		336	}
-		337
324	/*	338	/*
325	* Check if we know a file system with the same name as is in fs_name.	339	* Check if we know a file system with the same name as is in fs_name.
326	* This will also give us its file system handle.	340	* This will also give us its file system handle.
327	*/	341	*/
328	fs_handle_t fs_handle = fs_name_to_handle(fs_name, true);	342	fs_handle_t fs_handle = fs_name_to_handle(fs_name, true);
329	if (!fs_handle) {	343	if (!fs_handle) {
330	if (flags & IPC_FLAG_BLOCKING) {	344	if (flags & IPC_FLAG_BLOCKING) {
-		345	pending_req_t *pr;
-		346
331	/* Blocking mount, add to pending list */	347	/* Blocking mount, add to pending list */
332	pending_req_t pr = (pending_req_t ) malloc(sizeof(pending_req_t));	348	pr = (pending_req_t *) malloc(sizeof(pending_req_t));
333	if (!pr) {	349	if (!pr) {
334	ipc_answer_0(callid, ENOMEM);	350	ipc_answer_0(callid, ENOMEM);
335	ipc_answer_0(rid, ENOMEM);	351	ipc_answer_0(rid, ENOMEM);
336	free(mp);	352	free(mp);
337	free(fs_name);	353	free(fs_name);
338	return;	354	return;
339	}	355	}
340		356
341	pr->fs_name = fs_name;	357	pr->fs_name = fs_name;
342	pr->mp = mp;	358	pr->mp = mp;
343	pr->callid = callid;	359	pr->callid = callid;
344	pr->rid = rid;	360	pr->rid = rid;
345	pr->dev_handle = dev_handle;	361	pr->dev_handle = dev_handle;
346	link_initialize(&pr->link);	362	link_initialize(&pr->link);
347	list_append(&pr->link, &pending_req);	363	list_append(&pr->link, &pending_req);
348	return;	364	return;
349	}	365	}
350		366
351	ipc_answer_0(callid, ENOENT);	367	ipc_answer_0(callid, ENOENT);
352	ipc_answer_0(rid, ENOENT);	368	ipc_answer_0(rid, ENOENT);
353	free(mp);	369	free(mp);
354	free(fs_name);	370	free(fs_name);
355	return;	371	return;
356	}	372	}
357		373
358	/* Acknowledge that we know fs_name. */	374	/* Acknowledge that we know fs_name. */
359	ipc_answer_0(callid, EOK);	375	ipc_answer_0(callid, EOK);
360		376
361	/* Do the mount */	377	/* Do the mount */
362	vfs_mount_internal(rid, dev_handle, fs_handle, mp);	378	vfs_mount_internal(rid, dev_handle, fs_handle, mp);
363	free(mp);	379	free(mp);
364	free(fs_name);	380	free(fs_name);
365	}	381	}
366		382
367	void vfs_open(ipc_callid_t rid, ipc_call_t *request)	383	void vfs_open(ipc_callid_t rid, ipc_call_t *request)
368	{	384	{
369	if (!vfs_files_init()) {	385	if (!vfs_files_init()) {
370	ipc_answer_0(rid, ENOMEM);	386	ipc_answer_0(rid, ENOMEM);
371	return;	387	return;
372	}	388	}
373		389
374	/*	390	/*
375	* The POSIX interface is open(path, oflag, mode).	391	* The POSIX interface is open(path, oflag, mode).
376	* We can receive oflags and mode along with the VFS_OPEN call; the path	392	* We can receive oflags and mode along with the VFS_OPEN call; the path
377	* will need to arrive in another call.	393	* will need to arrive in another call.
378	*	394	*
379	* We also receive one private, non-POSIX set of flags called lflag	395	* We also receive one private, non-POSIX set of flags called lflag
380	* used to pass information to vfs_lookup_internal().	396	* used to pass information to vfs_lookup_internal().
381	*/	397	*/
382	int lflag = IPC_GET_ARG1(*request);	398	int lflag = IPC_GET_ARG1(*request);
383	int oflag = IPC_GET_ARG2(*request);	399	int oflag = IPC_GET_ARG2(*request);
384	int mode = IPC_GET_ARG3(*request);	400	int mode = IPC_GET_ARG3(*request);
385	size_t len;	401	size_t len;
386		402
387	/*	403	/*
388	* Make sure that we are called with exactly one of L_FILE and	404	* Make sure that we are called with exactly one of L_FILE and
389	* L_DIRECTORY.	405	* L_DIRECTORY.
390	*/	406	*/
391	if ((lflag & (L_FILE \| L_DIRECTORY)) == 0 \|\|	407	if ((lflag & (L_FILE \| L_DIRECTORY)) == 0 \|\|
392	(lflag & (L_FILE \| L_DIRECTORY)) == (L_FILE \| L_DIRECTORY)) {	408	(lflag & (L_FILE \| L_DIRECTORY)) == (L_FILE \| L_DIRECTORY)) {
393	ipc_answer_0(rid, EINVAL);	409	ipc_answer_0(rid, EINVAL);
394	return;	410	return;
395	}	411	}
396		412
397	if (oflag & O_CREAT)	413	if (oflag & O_CREAT)
398	lflag \|= L_CREATE;	414	lflag \|= L_CREATE;
399	if (oflag & O_EXCL)	415	if (oflag & O_EXCL)
400	lflag \|= L_EXCLUSIVE;	416	lflag \|= L_EXCLUSIVE;
401		417
402	ipc_callid_t callid;	418	ipc_callid_t callid;
403		419
404	if (!ipc_data_write_receive(&callid, &len)) {	420	if (!ipc_data_write_receive(&callid, &len)) {
405	ipc_answer_0(callid, EINVAL);	421	ipc_answer_0(callid, EINVAL);
406	ipc_answer_0(rid, EINVAL);	422	ipc_answer_0(rid, EINVAL);
407	return;	423	return;
408	}	424	}
409	char *path = malloc(len + 1);	425	char *path = malloc(len + 1);
410	if (!path) {	426	if (!path) {
411	ipc_answer_0(callid, ENOMEM);	427	ipc_answer_0(callid, ENOMEM);
412	ipc_answer_0(rid, ENOMEM);	428	ipc_answer_0(rid, ENOMEM);
413	return;	429	return;
414	}	430	}
415	int rc;	431	int rc;
416	if ((rc = ipc_data_write_finalize(callid, path, len))) {	432	if ((rc = ipc_data_write_finalize(callid, path, len))) {
417	ipc_answer_0(rid, rc);	433	ipc_answer_0(rid, rc);
418	free(path);	434	free(path);
419	return;	435	return;
420	}	436	}
421	path[len] = '\0';	437	path[len] = '\0';
422		438
423	/*	439	/*
424	* Avoid the race condition in which the file can be deleted before we	440	* Avoid the race condition in which the file can be deleted before we
425	* find/create-and-lock the VFS node corresponding to the looked-up	441	* find/create-and-lock the VFS node corresponding to the looked-up
426	* triplet.	442	* triplet.
427	*/	443	*/
428	if (lflag & L_CREATE)	444	if (lflag & L_CREATE)
429	rwlock_write_lock(&namespace_rwlock);	445	rwlock_write_lock(&namespace_rwlock);
430	else	446	else
431	rwlock_read_lock(&namespace_rwlock);	447	rwlock_read_lock(&namespace_rwlock);
432		448
433	/* The path is now populated and we can call vfs_lookup_internal(). */	449	/* The path is now populated and we can call vfs_lookup_internal(). */
434	vfs_lookup_res_t lr;	450	vfs_lookup_res_t lr;
435	rc = vfs_lookup_internal(path, lflag, &lr, NULL);	451	rc = vfs_lookup_internal(path, lflag, &lr, NULL);
436	if (rc) {	452	if (rc) {
437	if (lflag & L_CREATE)	453	if (lflag & L_CREATE)
438	rwlock_write_unlock(&namespace_rwlock);	454	rwlock_write_unlock(&namespace_rwlock);
439	else	455	else
440	rwlock_read_unlock(&namespace_rwlock);	456	rwlock_read_unlock(&namespace_rwlock);
441	ipc_answer_0(rid, rc);	457	ipc_answer_0(rid, rc);
442	free(path);	458	free(path);
443	return;	459	return;
444	}	460	}
445		461
446	/* Path is no longer needed. */	462	/* Path is no longer needed. */
447	free(path);	463	free(path);
448		464
449	vfs_node_t *node = vfs_node_get(&lr);	465	vfs_node_t *node = vfs_node_get(&lr);
450	if (lflag & L_CREATE)	466	if (lflag & L_CREATE)
451	rwlock_write_unlock(&namespace_rwlock);	467	rwlock_write_unlock(&namespace_rwlock);
452	else	468	else
453	rwlock_read_unlock(&namespace_rwlock);	469	rwlock_read_unlock(&namespace_rwlock);
454		470
455	/* Truncate the file if requested and if necessary. */	471	/* Truncate the file if requested and if necessary. */
456	if (oflag & O_TRUNC) {	472	if (oflag & O_TRUNC) {
457	rwlock_write_lock(&node->contents_rwlock);	473	rwlock_write_lock(&node->contents_rwlock);
458	if (node->size) {	474	if (node->size) {
459	rc = vfs_truncate_internal(node->fs_handle,	475	rc = vfs_truncate_internal(node->fs_handle,
460	node->dev_handle, node->index, 0);	476	node->dev_handle, node->index, 0);
461	if (rc) {	477	if (rc) {
462	rwlock_write_unlock(&node->contents_rwlock);	478	rwlock_write_unlock(&node->contents_rwlock);
463	vfs_node_put(node);	479	vfs_node_put(node);
464	ipc_answer_0(rid, rc);	480	ipc_answer_0(rid, rc);
465	return;	481	return;
466	}	482	}
467	node->size = 0;	483	node->size = 0;
468	}	484	}
469	rwlock_write_unlock(&node->contents_rwlock);	485	rwlock_write_unlock(&node->contents_rwlock);
470	}	486	}
471		487
472	/*	488	/*
473	* Get ourselves a file descriptor and the corresponding vfs_file_t	489	* Get ourselves a file descriptor and the corresponding vfs_file_t
474	* structure.	490	* structure.
475	*/	491	*/
476	int fd = vfs_fd_alloc();	492	int fd = vfs_fd_alloc();
477	if (fd < 0) {	493	if (fd < 0) {
478	vfs_node_put(node);	494	vfs_node_put(node);
479	ipc_answer_0(rid, fd);	495	ipc_answer_0(rid, fd);
480	return;	496	return;
481	}	497	}
482	vfs_file_t *file = vfs_file_get(fd);	498	vfs_file_t *file = vfs_file_get(fd);
483	file->node = node;	499	file->node = node;
484	if (oflag & O_APPEND)	500	if (oflag & O_APPEND)

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(root)/trunk/uspace/srv/vfs/vfs_ops.c @ 4759 – Rev 4301 → 4302