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 */
    char *opts;       /**< Mount options. */
    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, char *opts)
{
    vfs_lookup_res_t mp_res;
    vfs_lookup_res_t mr_res;
    vfs_node_t *mp_node = NULL;
    vfs_node_t *mr_node;
    fs_index_t rindex;
    size_t rsize;
    unsigned rlnkcnt;
    ipcarg_t rc;
    int phone;
    aid_t msg;
    ipc_call_t answer;
           
 
    /* Resolve the path to the mountpoint. */
    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) {
            /*
             * For this simple, but important case,
             * we are almost done.
             */
           
            /* Tell the mountee that it is being mounted. */
            phone = vfs_grab_phone(fs_handle);
            msg = async_send_1(phone, VFS_MOUNTED,
                (ipcarg_t) dev_handle, &answer);
            /* send the mount options */
            rc = ipc_data_write_start(phone, (void *)opts,
                str_size(opts));
            if (rc != EOK) {
                async_wait_for(msg, NULL);
                vfs_release_phone(phone);
                futex_up(&rootfs_futex);
                ipc_answer_0(rid, rc);
                return;
            }
            async_wait_for(msg, &rc);
            vfs_release_phone(phone);
           
            if (rc != EOK) {
                futex_up(&rootfs_futex);
                ipc_answer_0(rid, rc);
                return;
            }
 
            rindex = (fs_index_t) IPC_GET_ARG1(answer);
            rsize = (size_t) IPC_GET_ARG2(answer);
            rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
           
            mr_res.triplet.fs_handle = fs_handle;
            mr_res.triplet.dev_handle = dev_handle;
            mr_res.triplet.index = rindex;
            mr_res.size = rsize;
            mr_res.lnkcnt = 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.
     */
   
    int mountee_phone = vfs_grab_phone(fs_handle);
    assert(mountee_phone >= 0);
    vfs_release_phone(mountee_phone);
 
    phone = vfs_grab_phone(mp_res.triplet.fs_handle);
    msg = async_send_4(phone, VFS_MOUNT,
        (ipcarg_t) mp_res.triplet.dev_handle,
        (ipcarg_t) mp_res.triplet.index,
        (ipcarg_t) fs_handle,
        (ipcarg_t) dev_handle, &answer);
   
    /* send connection */
    rc = async_req_1_0(phone, IPC_M_CONNECTION_CLONE, mountee_phone);
    if (rc != EOK) {
        async_wait_for(msg, NULL);
        vfs_release_phone(phone);
        /* Mount failed, drop reference to mp_node. */
        if (mp_node)
            vfs_node_put(mp_node);
        ipc_answer_0(rid, rc);
        return;
    }
   
    /* send the mount options */
    rc = ipc_data_write_start(phone, (void *)opts, str_size(opts));
    if (rc != EOK) {
        async_wait_for(msg, NULL);
        vfs_release_phone(phone);
        /* Mount failed, drop reference to mp_node. */
        if (mp_node)
            vfs_node_put(mp_node);
        ipc_answer_0(rid, rc);
        return;
    }
    async_wait_for(msg, &rc);
    vfs_release_phone(phone);
   
    if (rc != EOK) {
        /* Mount failed, drop reference to mp_node. */
        if (mp_node)
            vfs_node_put(mp_node);
    }
   
    rindex = (fs_index_t) IPC_GET_ARG1(answer);
    rsize = (size_t) IPC_GET_ARG2(answer);
    rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
   
    mr_res.triplet.fs_handle = fs_handle;
    mr_res.triplet.dev_handle = dev_handle;
    mr_res.triplet.index = rindex;
    mr_res.size = rsize;
    mr_res.lnkcnt = rlnkcnt;
    mr_res.type = VFS_NODE_DIRECTORY;
   
    /* Add reference to the mounted root. */
    mr_node = vfs_node_get(&mr_res);
    assert(mr_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,
            pr->opts);
       
        free(pr->fs_name);
        free(pr->mp);
        free(pr->opts);
        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 to receive the mount options. */
    if (!ipc_data_write_receive(&callid, &size)) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        free(mp);
        return;
    }
 
    /* Check the offered options size. */
    if (size < 0 || size > MAX_MNTOPTS_LEN) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        free(mp);
        return;
    }
 
    /* Allocate buffer for the mount options. */
    char *opts = (char *) malloc(size + 1);
    if (!opts) {
        ipc_answer_0(callid, ENOMEM);
        ipc_answer_0(rid, ENOMEM);
        free(mp);
        return;
    }
 
    /* Deliver the mount options. */
    retval = ipc_data_write_finalize(callid, opts, size);
    if (retval != EOK) {
        ipc_answer_0(rid, retval);
        free(mp);
        free(opts);
        return;
    }
    opts[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);
        free(opts);
        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);
        free(opts);
        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);
        free(opts);
        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(opts);
        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(opts);
        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);
                free(opts);
                return;
            }
           
            pr->fs_name = fs_name;
            pr->mp = mp;
            pr->opts = opts;
            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);
        free(opts);
        return;
    }
   
    /* Acknowledge that we know fs_name. */
    ipc_answer_0(callid, EOK);
   
    /* Do the mount */
    vfs_mount_internal(rid, dev_handle, fs_handle, mp, opts);
    free(mp);
    free(fs_name);
    free(opts);
}
 
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))) &&
        ((newc[str_length(oldc)] == '/') ||
        (str_length(oldc) == 1) ||
        (str_length(oldc) == str_length(newc)))) {
            /*
         * oldc is a prefix of newc and either
         * - newc continues with a / where oldc ends, or
         * - oldc was / itself, or
         * - oldc and newc are equal.
         */
        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;
    }
    /* Determine the path to the parent of the node with the new name. */
    char *parentc = str_dup(newc);
    if (!parentc) {
        rwlock_write_unlock(&namespace_rwlock);
        ipc_answer_0(rid, rc);
        free(old);
        free(new);
        return;
    }
    char *lastsl = str_rchr(parentc + 1, '/');
    if (lastsl)
        *lastsl = '\0';
    else
        parentc[1] = '\0';
    /* Lookup parent of the new file name. */
    rc = vfs_lookup_internal(parentc, L_NONE, &new_par_lr, NULL);
    free(parentc);  /* not needed anymore */
    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 4409	Rev 4427
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	char opts; /< Mount options. /	63	char opts; /< Mount options. /
64	ipc_callid_t callid; /*< Call ID waiting for the mount /	64	ipc_callid_t callid; /*< Call ID waiting for the mount /
65	ipc_callid_t rid; /*< Request ID /	65	ipc_callid_t rid; /*< Request ID /
66	dev_handle_t dev_handle; /*< Device handle /	66	dev_handle_t dev_handle; /*< Device handle /
67	} pending_req_t;	67	} pending_req_t;
68		68
69	LIST_INITIALIZE(pending_req);	69	LIST_INITIALIZE(pending_req);
70		70
71	/**	71	/**
72	* This rwlock prevents the race between a triplet-to-VFS-node resolution and a	72	* This rwlock prevents the race between a triplet-to-VFS-node resolution and a
73	* concurrent VFS operation which modifies the file system namespace.	73	* concurrent VFS operation which modifies the file system namespace.
74	*/	74	*/
75	RWLOCK_INITIALIZE(namespace_rwlock);	75	RWLOCK_INITIALIZE(namespace_rwlock);
76		76
77	futex_t rootfs_futex = FUTEX_INITIALIZER;	77	futex_t rootfs_futex = FUTEX_INITIALIZER;
78	vfs_pair_t rootfs = {	78	vfs_pair_t rootfs = {
79	.fs_handle = 0,	79	.fs_handle = 0,
80	.dev_handle = 0	80	.dev_handle = 0
81	};	81	};
82		82
83	static void vfs_mount_internal(ipc_callid_t rid, dev_handle_t dev_handle,	83	static void vfs_mount_internal(ipc_callid_t rid, dev_handle_t dev_handle,
84	fs_handle_t fs_handle, char mp, char opts)	84	fs_handle_t fs_handle, char mp, char opts)
85	{	85	{
86	vfs_lookup_res_t mp_res;	86	vfs_lookup_res_t mp_res;
87	vfs_lookup_res_t mr_res;	87	vfs_lookup_res_t mr_res;
88	vfs_node_t *mp_node = NULL;	88	vfs_node_t *mp_node = NULL;
89	vfs_node_t *mr_node;	89	vfs_node_t *mr_node;
90	fs_index_t rindex;	90	fs_index_t rindex;
91	size_t rsize;	91	size_t rsize;
92	unsigned rlnkcnt;	92	unsigned rlnkcnt;
93	ipcarg_t rc;	93	ipcarg_t rc;
94	int phone;	94	int phone;
95	aid_t msg;	95	aid_t msg;
96	ipc_call_t answer;	96	ipc_call_t answer;
97		97
98		98
99	/* Resolve the path to the mountpoint. */	99	/* Resolve the path to the mountpoint. */
100	futex_down(&rootfs_futex);	100	futex_down(&rootfs_futex);
101	if (rootfs.fs_handle) {	101	if (rootfs.fs_handle) {
102	/* We already have the root FS. */	102	/* We already have the root FS. */
103	rwlock_write_lock(&namespace_rwlock);	103	rwlock_write_lock(&namespace_rwlock);
104	if (str_cmp(mp, "/") == 0) {	104	if (str_cmp(mp, "/") == 0) {
105	/* Trying to mount root FS over root FS */	105	/* Trying to mount root FS over root FS */
106	rwlock_write_unlock(&namespace_rwlock);	106	rwlock_write_unlock(&namespace_rwlock);
107	futex_up(&rootfs_futex);	107	futex_up(&rootfs_futex);
108	ipc_answer_0(rid, EBUSY);	108	ipc_answer_0(rid, EBUSY);
109	return;	109	return;
110	}	110	}
111		111
112	rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);	112	rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);
113	if (rc != EOK) {	113	if (rc != EOK) {
114	/* The lookup failed for some reason. */	114	/* The lookup failed for some reason. */
115	rwlock_write_unlock(&namespace_rwlock);	115	rwlock_write_unlock(&namespace_rwlock);
116	futex_up(&rootfs_futex);	116	futex_up(&rootfs_futex);
117	ipc_answer_0(rid, rc);	117	ipc_answer_0(rid, rc);
118	return;	118	return;
119	}	119	}
120		120
121	mp_node = vfs_node_get(&mp_res);	121	mp_node = vfs_node_get(&mp_res);
122	if (!mp_node) {	122	if (!mp_node) {
123	rwlock_write_unlock(&namespace_rwlock);	123	rwlock_write_unlock(&namespace_rwlock);
124	futex_up(&rootfs_futex);	124	futex_up(&rootfs_futex);
125	ipc_answer_0(rid, ENOMEM);	125	ipc_answer_0(rid, ENOMEM);
126	return;	126	return;
127	}	127	}
128		128
129	/*	129	/*
130	* Now we hold a reference to mp_node.	130	* Now we hold a reference to mp_node.
131	* It will be dropped upon the corresponding VFS_UNMOUNT.	131	* It will be dropped upon the corresponding VFS_UNMOUNT.
132	* This prevents the mount point from being deleted.	132	* This prevents the mount point from being deleted.
133	*/	133	*/
134	rwlock_write_unlock(&namespace_rwlock);	134	rwlock_write_unlock(&namespace_rwlock);
135	} else {	135	} else {
136	/* We still don't have the root file system mounted. */	136	/* We still don't have the root file system mounted. */
137	if (str_cmp(mp, "/") == 0) {	137	if (str_cmp(mp, "/") == 0) {
138	/*	138	/*
139	* For this simple, but important case,	139	* For this simple, but important case,
140	* we are almost done.	140	* we are almost done.
141	*/	141	*/
142		142
143	/* Tell the mountee that it is being mounted. */	143	/* Tell the mountee that it is being mounted. */
144	phone = vfs_grab_phone(fs_handle);	144	phone = vfs_grab_phone(fs_handle);
145	msg = async_send_1(phone, VFS_MOUNTED,	145	msg = async_send_1(phone, VFS_MOUNTED,
146	(ipcarg_t) dev_handle, &answer);	146	(ipcarg_t) dev_handle, &answer);
147	/* send the mount options */	147	/* send the mount options */
148	rc = ipc_data_write_start(phone, (void *)opts,	148	rc = ipc_data_write_start(phone, (void *)opts,
149	str_size(opts));	149	str_size(opts));
150	if (rc != EOK) {	150	if (rc != EOK) {
151	async_wait_for(msg, NULL);	151	async_wait_for(msg, NULL);
152	vfs_release_phone(phone);	152	vfs_release_phone(phone);
153	futex_up(&rootfs_futex);	153	futex_up(&rootfs_futex);
154	ipc_answer_0(rid, rc);	154	ipc_answer_0(rid, rc);
155	return;	155	return;
156	}	156	}
157	async_wait_for(msg, &rc);	157	async_wait_for(msg, &rc);
158	vfs_release_phone(phone);	158	vfs_release_phone(phone);
159		159
160	if (rc != EOK) {	160	if (rc != EOK) {
161	futex_up(&rootfs_futex);	161	futex_up(&rootfs_futex);
162	ipc_answer_0(rid, rc);	162	ipc_answer_0(rid, rc);
163	return;	163	return;
164	}	164	}
165		165
166	rindex = (fs_index_t) IPC_GET_ARG1(answer);	166	rindex = (fs_index_t) IPC_GET_ARG1(answer);
167	rsize = (size_t) IPC_GET_ARG2(answer);	167	rsize = (size_t) IPC_GET_ARG2(answer);
168	rlnkcnt = (unsigned) IPC_GET_ARG3(answer);	168	rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
169		169
170	mr_res.triplet.fs_handle = fs_handle;	170	mr_res.triplet.fs_handle = fs_handle;
171	mr_res.triplet.dev_handle = dev_handle;	171	mr_res.triplet.dev_handle = dev_handle;
172	mr_res.triplet.index = rindex;	172	mr_res.triplet.index = rindex;
173	mr_res.size = rsize;	173	mr_res.size = rsize;
174	mr_res.lnkcnt = rlnkcnt;	174	mr_res.lnkcnt = rlnkcnt;
175	mr_res.type = VFS_NODE_DIRECTORY;	175	mr_res.type = VFS_NODE_DIRECTORY;
176		176
177	rootfs.fs_handle = fs_handle;	177	rootfs.fs_handle = fs_handle;
178	rootfs.dev_handle = dev_handle;	178	rootfs.dev_handle = dev_handle;
179	futex_up(&rootfs_futex);	179	futex_up(&rootfs_futex);
180		180
181	/* Add reference to the mounted root. */	181	/* Add reference to the mounted root. */
182	mr_node = vfs_node_get(&mr_res);	182	mr_node = vfs_node_get(&mr_res);
183	assert(mr_node);	183	assert(mr_node);
184		184
185	ipc_answer_0(rid, rc);	185	ipc_answer_0(rid, rc);
186	return;	186	return;
187	} else {	187	} else {
188	/*	188	/*
189	* We can't resolve this without the root filesystem	189	* We can't resolve this without the root filesystem
190	* being mounted first.	190	* being mounted first.
191	*/	191	*/
192	futex_up(&rootfs_futex);	192	futex_up(&rootfs_futex);
193	ipc_answer_0(rid, ENOENT);	193	ipc_answer_0(rid, ENOENT);
194	return;	194	return;
195	}	195	}
196	}	196	}
197	futex_up(&rootfs_futex);	197	futex_up(&rootfs_futex);
198		198
199	/*	199	/*
200	* At this point, we have all necessary pieces: file system and device	200	* At this point, we have all necessary pieces: file system and device
201	* handles, and we know the mount point VFS node.	201	* handles, and we know the mount point VFS node.
202	*/	202	*/
203		203
204	int mountee_phone = vfs_grab_phone(fs_handle);	204	int mountee_phone = vfs_grab_phone(fs_handle);
205	assert(mountee_phone >= 0);	205	assert(mountee_phone >= 0);
206	vfs_release_phone(mountee_phone);	206	vfs_release_phone(mountee_phone);
207		207
208	phone = vfs_grab_phone(mp_res.triplet.fs_handle);	208	phone = vfs_grab_phone(mp_res.triplet.fs_handle);
209	msg = async_send_4(phone, VFS_MOUNT,	209	msg = async_send_4(phone, VFS_MOUNT,
210	(ipcarg_t) mp_res.triplet.dev_handle,	210	(ipcarg_t) mp_res.triplet.dev_handle,
211	(ipcarg_t) mp_res.triplet.index,	211	(ipcarg_t) mp_res.triplet.index,
212	(ipcarg_t) fs_handle,	212	(ipcarg_t) fs_handle,
213	(ipcarg_t) dev_handle, &answer);	213	(ipcarg_t) dev_handle, &answer);
214		214
215	/* send connection */	215	/* send connection */
216	rc = async_req_1_0(phone, IPC_M_CONNECTION_CLONE, mountee_phone);	216	rc = async_req_1_0(phone, IPC_M_CONNECTION_CLONE, mountee_phone);
217	if (rc != EOK) {	217	if (rc != EOK) {
218	async_wait_for(msg, NULL);	218	async_wait_for(msg, NULL);
219	vfs_release_phone(phone);	219	vfs_release_phone(phone);
220	/* Mount failed, drop reference to mp_node. */	220	/* Mount failed, drop reference to mp_node. */
221	if (mp_node)	221	if (mp_node)
222	vfs_node_put(mp_node);	222	vfs_node_put(mp_node);
223	ipc_answer_0(rid, rc);	223	ipc_answer_0(rid, rc);
224	return;	224	return;
225	}	225	}
226		226
227	/* send the mount options */	227	/* send the mount options */
228	rc = ipc_data_write_start(phone, (void *)opts, str_size(opts));	228	rc = ipc_data_write_start(phone, (void *)opts, str_size(opts));
229	if (rc != EOK) {	229	if (rc != EOK) {
230	async_wait_for(msg, NULL);	230	async_wait_for(msg, NULL);
231	vfs_release_phone(phone);	231	vfs_release_phone(phone);
232	/* Mount failed, drop reference to mp_node. */	232	/* Mount failed, drop reference to mp_node. */
233	if (mp_node)	233	if (mp_node)
234	vfs_node_put(mp_node);	234	vfs_node_put(mp_node);
235	ipc_answer_0(rid, rc);	235	ipc_answer_0(rid, rc);
236	return;	236	return;
237	}	237	}
238	async_wait_for(msg, &rc);	238	async_wait_for(msg, &rc);
239	vfs_release_phone(phone);	239	vfs_release_phone(phone);
240		240
241	if (rc != EOK) {	241	if (rc != EOK) {
242	/* Mount failed, drop reference to mp_node. */	242	/* Mount failed, drop reference to mp_node. */
243	if (mp_node)	243	if (mp_node)
244	vfs_node_put(mp_node);	244	vfs_node_put(mp_node);
245	}	245	}
246		246
247	rindex = (fs_index_t) IPC_GET_ARG1(answer);	247	rindex = (fs_index_t) IPC_GET_ARG1(answer);
248	rsize = (size_t) IPC_GET_ARG2(answer);	248	rsize = (size_t) IPC_GET_ARG2(answer);
249	rlnkcnt = (unsigned) IPC_GET_ARG3(answer);	249	rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
250		250
251	mr_res.triplet.fs_handle = fs_handle;	251	mr_res.triplet.fs_handle = fs_handle;
252	mr_res.triplet.dev_handle = dev_handle;	252	mr_res.triplet.dev_handle = dev_handle;
253	mr_res.triplet.index = rindex;	253	mr_res.triplet.index = rindex;
254	mr_res.size = rsize;	254	mr_res.size = rsize;
255	mr_res.lnkcnt = rlnkcnt;	255	mr_res.lnkcnt = rlnkcnt;
256	mr_res.type = VFS_NODE_DIRECTORY;	256	mr_res.type = VFS_NODE_DIRECTORY;
257		257
258	/* Add reference to the mounted root. */	258	/* Add reference to the mounted root. */
259	mr_node = vfs_node_get(&mr_res);	259	mr_node = vfs_node_get(&mr_res);
260	assert(mr_node);	260	assert(mr_node);
261		261
262	ipc_answer_0(rid, rc);	262	ipc_answer_0(rid, rc);
263	}	263	}
264		264
265	/** Process pending mount requests */	265	/** Process pending mount requests */
266	void vfs_process_pending_mount()	266	void vfs_process_pending_mount()
267	{	267	{
268	link_t *cur;	268	link_t *cur;
269		269
270	loop:	270	loop:
271	for (cur = pending_req.next; cur != &pending_req; cur = cur->next) {	271	for (cur = pending_req.next; cur != &pending_req; cur = cur->next) {
272	pending_req_t *pr = list_get_instance(cur, pending_req_t, link);	272	pending_req_t *pr = list_get_instance(cur, pending_req_t, link);
273		273
274	fs_handle_t fs_handle = fs_name_to_handle(pr->fs_name, true);	274	fs_handle_t fs_handle = fs_name_to_handle(pr->fs_name, true);
275	if (!fs_handle)	275	if (!fs_handle)
276	continue;	276	continue;
277		277
278	/* Acknowledge that we know fs_name. */	278	/* Acknowledge that we know fs_name. */
279	ipc_answer_0(pr->callid, EOK);	279	ipc_answer_0(pr->callid, EOK);
280		280
281	/* Do the mount */	281	/* Do the mount */
282	vfs_mount_internal(pr->rid, pr->dev_handle, fs_handle, pr->mp,	282	vfs_mount_internal(pr->rid, pr->dev_handle, fs_handle, pr->mp,
283	pr->opts);	283	pr->opts);
284		284
285	free(pr->fs_name);	285	free(pr->fs_name);
286	free(pr->mp);	286	free(pr->mp);
287	free(pr->opts);	287	free(pr->opts);
288	list_remove(cur);	288	list_remove(cur);
289	free(pr);	289	free(pr);
290	goto loop;	290	goto loop;
291	}	291	}
292	}	292	}
293		293
294	void vfs_mount(ipc_callid_t rid, ipc_call_t *request)	294	void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
295	{	295	{
296	/*	296	/*
297	* We expect the library to do the device-name to device-handle	297	* We expect the library to do the device-name to device-handle
298	* translation for us, thus the device handle will arrive as ARG1	298	* translation for us, thus the device handle will arrive as ARG1
299	* in the request.	299	* in the request.
300	*/	300	*/
301	dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);	301	dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
302		302
303	/*	303	/*
304	* Mount flags are passed as ARG2.	304	* Mount flags are passed as ARG2.
305	*/	305	*/
306	unsigned int flags = (unsigned int) IPC_GET_ARG2(*request);	306	unsigned int flags = (unsigned int) IPC_GET_ARG2(*request);
307		307
308	/*	308	/*
309	* For now, don't make use of ARG3, but it can be used to	309	* For now, don't make use of ARG3, but it can be used to
310	* carry mount options in the future.	310	* carry mount options in the future.
311	*/	311	*/
312		312
313	/* We want the client to send us the mount point. */	313	/* We want the client to send us the mount point. */
314	ipc_callid_t callid;	314	ipc_callid_t callid;
315	size_t size;	315	size_t size;
316	if (!ipc_data_write_receive(&callid, &size)) {	316	if (!ipc_data_write_receive(&callid, &size)) {
317	ipc_answer_0(callid, EINVAL);	317	ipc_answer_0(callid, EINVAL);
318	ipc_answer_0(rid, EINVAL);	318	ipc_answer_0(rid, EINVAL);
319	return;	319	return;
320	}	320	}
321		321
322	/* Check whether size is reasonable wrt. the mount point. */	322	/* Check whether size is reasonable wrt. the mount point. */
323	if ((size < 1) \|\| (size > MAX_PATH_LEN)) {	323	if ((size < 1) \|\| (size > MAX_PATH_LEN)) {
324	ipc_answer_0(callid, EINVAL);	324	ipc_answer_0(callid, EINVAL);
325	ipc_answer_0(rid, EINVAL);	325	ipc_answer_0(rid, EINVAL);
326	return;	326	return;
327	}	327	}
328		328
329	/* Allocate buffer for the mount point data being received. */	329	/* Allocate buffer for the mount point data being received. */
330	char *mp = malloc(size + 1);	330	char *mp = malloc(size + 1);
331	if (!mp) {	331	if (!mp) {
332	ipc_answer_0(callid, ENOMEM);	332	ipc_answer_0(callid, ENOMEM);
333	ipc_answer_0(rid, ENOMEM);	333	ipc_answer_0(rid, ENOMEM);
334	return;	334	return;
335	}	335	}
336		336
337	/* Deliver the mount point. */	337	/* Deliver the mount point. */
338	ipcarg_t retval = ipc_data_write_finalize(callid, mp, size);	338	ipcarg_t retval = ipc_data_write_finalize(callid, mp, size);
339	if (retval != EOK) {	339	if (retval != EOK) {
340	ipc_answer_0(rid, retval);	340	ipc_answer_0(rid, retval);
341	free(mp);	341	free(mp);
342	return;	342	return;
343	}	343	}
344	mp[size] = '\0';	344	mp[size] = '\0';
345		345
346	/* Now we expect to receive the mount options. */	346	/* Now we expect to receive the mount options. */
347	if (!ipc_data_write_receive(&callid, &size)) {	347	if (!ipc_data_write_receive(&callid, &size)) {
348	ipc_answer_0(callid, EINVAL);	348	ipc_answer_0(callid, EINVAL);
349	ipc_answer_0(rid, EINVAL);	349	ipc_answer_0(rid, EINVAL);
350	free(mp);	350	free(mp);
351	return;	351	return;
352	}	352	}
353		353
354	/* Check the offered options size. */	354	/* Check the offered options size. */
355	if (size < 0 \|\| size > MAX_MNTOPTS_LEN) {	355	if (size < 0 \|\| size > MAX_MNTOPTS_LEN) {
356	ipc_answer_0(callid, EINVAL);	356	ipc_answer_0(callid, EINVAL);
357	ipc_answer_0(rid, EINVAL);	357	ipc_answer_0(rid, EINVAL);
358	free(mp);	358	free(mp);
359	return;	359	return;
360	}	360	}
361		361
362	/* Allocate buffer for the mount options. */	362	/* Allocate buffer for the mount options. */
363	char opts = (char ) malloc(size + 1);	363	char opts = (char ) malloc(size + 1);
364	if (!opts) {	364	if (!opts) {
365	ipc_answer_0(callid, ENOMEM);	365	ipc_answer_0(callid, ENOMEM);
366	ipc_answer_0(rid, ENOMEM);	366	ipc_answer_0(rid, ENOMEM);
367	free(mp);	367	free(mp);
368	return;	368	return;
369	}	369	}
370		370
371	/* Deliver the mount options. */	371	/* Deliver the mount options. */
372	retval = ipc_data_write_finalize(callid, opts, size);	372	retval = ipc_data_write_finalize(callid, opts, size);
373	if (retval != EOK) {	373	if (retval != EOK) {
374	ipc_answer_0(rid, retval);	374	ipc_answer_0(rid, retval);
375	free(mp);	375	free(mp);
376	free(opts);	376	free(opts);
377	return;	377	return;
378	}	378	}
379	opts[size] = '\0';	379	opts[size] = '\0';
380		380
381	/*	381	/*
382	* Now, we expect the client to send us data with the name of the file	382	* Now, we expect the client to send us data with the name of the file
383	* system.	383	* system.
384	*/	384	*/
385	if (!ipc_data_write_receive(&callid, &size)) {	385	if (!ipc_data_write_receive(&callid, &size)) {
386	ipc_answer_0(callid, EINVAL);	386	ipc_answer_0(callid, EINVAL);
387	ipc_answer_0(rid, EINVAL);	387	ipc_answer_0(rid, EINVAL);
388	free(mp);	388	free(mp);
389	free(opts);	389	free(opts);
390	return;	390	return;
391	}	391	}
392		392
393	/*	393	/*
394	* Don't receive more than is necessary for storing a full file system	394	* Don't receive more than is necessary for storing a full file system
395	* name.	395	* name.
396	*/	396	*/
397	if ((size < 1) \|\| (size > FS_NAME_MAXLEN)) {	397	if ((size < 1) \|\| (size > FS_NAME_MAXLEN)) {
398	ipc_answer_0(callid, EINVAL);	398	ipc_answer_0(callid, EINVAL);
399	ipc_answer_0(rid, EINVAL);	399	ipc_answer_0(rid, EINVAL);
400	free(mp);	400	free(mp);
401	free(opts);	401	free(opts);
402	return;	402	return;
403	}	403	}
404		404
405	/*	405	/*
406	* Allocate buffer for file system name.	406	* Allocate buffer for file system name.
407	*/	407	*/
408	char fs_name = (char ) malloc(size + 1);	408	char fs_name = (char ) malloc(size + 1);
409	if (fs_name == NULL) {	409	if (fs_name == NULL) {
410	ipc_answer_0(callid, ENOMEM);	410	ipc_answer_0(callid, ENOMEM);
411	ipc_answer_0(rid, ENOMEM);	411	ipc_answer_0(rid, ENOMEM);
412	free(mp);	412	free(mp);
413	free(opts);	413	free(opts);
414	return;	414	return;
415	}	415	}
416		416
417	/* Deliver the file system name. */	417	/* Deliver the file system name. */
418	retval = ipc_data_write_finalize(callid, fs_name, size);	418	retval = ipc_data_write_finalize(callid, fs_name, size);
419	if (retval != EOK) {	419	if (retval != EOK) {
420	ipc_answer_0(rid, retval);	420	ipc_answer_0(rid, retval);
421	free(mp);	421	free(mp);
422	free(opts);	422	free(opts);
423	free(fs_name);	423	free(fs_name);
424	return;	424	return;
425	}	425	}
426	fs_name[size] = '\0';	426	fs_name[size] = '\0';
427		427
428	/*	428	/*
429	* Wait for IPC_M_PING so that we can return an error if we don't know	429	* Wait for IPC_M_PING so that we can return an error if we don't know
430	* fs_name.	430	* fs_name.
431	*/	431	*/
432	ipc_call_t data;	432	ipc_call_t data;
433	callid = async_get_call(&data);	433	callid = async_get_call(&data);
434	if (IPC_GET_METHOD(data) != IPC_M_PING) {	434	if (IPC_GET_METHOD(data) != IPC_M_PING) {
435	ipc_answer_0(callid, ENOTSUP);	435	ipc_answer_0(callid, ENOTSUP);
436	ipc_answer_0(rid, ENOTSUP);	436	ipc_answer_0(rid, ENOTSUP);
437	free(mp);	437	free(mp);
438	free(opts);	438	free(opts);
439	free(fs_name);	439	free(fs_name);
440	return;	440	return;
441	}	441	}
442		442
443	/*	443	/*
444	* Check if we know a file system with the same name as is in fs_name.	444	* Check if we know a file system with the same name as is in fs_name.
445	* This will also give us its file system handle.	445	* This will also give us its file system handle.
446	*/	446	*/
447	fs_handle_t fs_handle = fs_name_to_handle(fs_name, true);	447	fs_handle_t fs_handle = fs_name_to_handle(fs_name, true);
448	if (!fs_handle) {	448	if (!fs_handle) {
449	if (flags & IPC_FLAG_BLOCKING) {	449	if (flags & IPC_FLAG_BLOCKING) {
450	pending_req_t *pr;	450	pending_req_t *pr;
451		451
452	/* Blocking mount, add to pending list */	452	/* Blocking mount, add to pending list */
453	pr = (pending_req_t *) malloc(sizeof(pending_req_t));	453	pr = (pending_req_t *) malloc(sizeof(pending_req_t));
454	if (!pr) {	454	if (!pr) {
455	ipc_answer_0(callid, ENOMEM);	455	ipc_answer_0(callid, ENOMEM);
456	ipc_answer_0(rid, ENOMEM);	456	ipc_answer_0(rid, ENOMEM);
457	free(mp);	457	free(mp);
458	free(fs_name);	458	free(fs_name);
459	free(opts);	459	free(opts);
460	return;	460	return;
461	}	461	}
462		462
463	pr->fs_name = fs_name;	463	pr->fs_name = fs_name;
464	pr->mp = mp;	464	pr->mp = mp;
465	pr->opts = opts;	465	pr->opts = opts;
466	pr->callid = callid;	466	pr->callid = callid;
467	pr->rid = rid;	467	pr->rid = rid;
468	pr->dev_handle = dev_handle;	468	pr->dev_handle = dev_handle;
469	link_initialize(&pr->link);	469	link_initialize(&pr->link);
470	list_append(&pr->link, &pending_req);	470	list_append(&pr->link, &pending_req);
471	return;	471	return;
472	}	472	}
473		473
474	ipc_answer_0(callid, ENOENT);	474	ipc_answer_0(callid, ENOENT);
475	ipc_answer_0(rid, ENOENT);	475	ipc_answer_0(rid, ENOENT);
476	free(mp);	476	free(mp);
477	free(fs_name);	477	free(fs_name);
478	free(opts);	478	free(opts);
479	return;	479	return;
480	}	480	}
481		481
482	/* Acknowledge that we know fs_name. */	482	/* Acknowledge that we know fs_name. */
483	ipc_answer_0(callid, EOK);	483	ipc_answer_0(callid, EOK);
484		484
485	/* Do the mount */	485	/* Do the mount */
486	vfs_mount_internal(rid, dev_handle, fs_handle, mp, opts);	486	vfs_mount_internal(rid, dev_handle, fs_handle, mp, opts);
487	free(mp);	487	free(mp);
488	free(fs_name);	488	free(fs_name);
489	free(opts);	489	free(opts);
490	}	490	}
491		491
492	void vfs_open(ipc_callid_t rid, ipc_call_t *request)	492	void vfs_open(ipc_callid_t rid, ipc_call_t *request)
493	{	493	{
494	if (!vfs_files_init()) {	494	if (!vfs_files_init()) {
495	ipc_answer_0(rid, ENOMEM);	495	ipc_answer_0(rid, ENOMEM);
496	return;	496	return;
497	}	497	}
498		498
499	/*	499	/*
500	* The POSIX interface is open(path, oflag, mode).	500	* The POSIX interface is open(path, oflag, mode).

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(root)/trunk/uspace/srv/vfs/vfs_ops.c @ 2733 – Rev 4409 → 4427