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);
 
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. */
    rwlock_write_lock(&namespace_rwlock);
    if (rootfs.fs_handle) {
        /* We already have the root FS. */
        if (str_cmp(mp, "/") == 0) {
            /* Trying to mount root FS over root FS */
            ipc_answer_0(rid, EBUSY);
            rwlock_write_unlock(&namespace_rwlock);
            return;
        }
       
        rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);
        if (rc != EOK) {
            /* The lookup failed for some reason. */
            ipc_answer_0(rid, rc);
            rwlock_write_unlock(&namespace_rwlock);
            return;
        }
       
        mp_node = vfs_node_get(&mp_res);
        if (!mp_node) {
            ipc_answer_0(rid, ENOMEM);
            rwlock_write_unlock(&namespace_rwlock);
            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.
         */
    } 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);
                ipc_answer_0(rid, rc);
                rwlock_write_unlock(&namespace_rwlock);
                return;
            }
            async_wait_for(msg, &rc);
            vfs_release_phone(phone);
           
            if (rc != EOK) {
                ipc_answer_0(rid, rc);
                rwlock_write_unlock(&namespace_rwlock);
                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;
           
            /* Add reference to the mounted root. */
            mr_node = vfs_node_get(&mr_res);
            assert(mr_node);
           
            ipc_answer_0(rid, rc);
            rwlock_write_unlock(&namespace_rwlock);
            return;
        } else {
            /*
             * We can't resolve this without the root filesystem
             * being mounted first.
             */
            ipc_answer_0(rid, ENOENT);
            rwlock_write_unlock(&namespace_rwlock);
            return;
        }
    }
   
    /*
     * 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);
        rwlock_write_unlock(&namespace_rwlock);
        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);
        rwlock_write_unlock(&namespace_rwlock);
        return;
    }
    async_wait_for(msg, &rc);
    vfs_release_phone(phone);
   
    if (rc == EOK) {
        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);
    } else {
        /* Mount failed, drop reference to mp_node. */
        if (mp_node)
            vfs_node_put(mp_node);
    }
 
    ipc_answer_0(rid, rc);
    rwlock_write_unlock(&namespace_rwlock);
}
 
/** Process pending mount requests */
void vfs_process_pending_mount(void)
{
    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 4443	Rev 4445
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	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, char opts)	83	fs_handle_t fs_handle, char mp, char opts)
84	{	84	{
85	vfs_lookup_res_t mp_res;	85	vfs_lookup_res_t mp_res;
86	vfs_lookup_res_t mr_res;	86	vfs_lookup_res_t mr_res;
87	vfs_node_t *mp_node = NULL;	87	vfs_node_t *mp_node = NULL;
88	vfs_node_t *mr_node;	88	vfs_node_t *mr_node;
89	fs_index_t rindex;	89	fs_index_t rindex;
90	size_t rsize;	90	size_t rsize;
91	unsigned rlnkcnt;	91	unsigned rlnkcnt;
92	ipcarg_t rc;	92	ipcarg_t rc;
93	int phone;	93	int phone;
94	aid_t msg;	94	aid_t msg;
95	ipc_call_t answer;	95	ipc_call_t answer;
96		96
97	/* Resolve the path to the mountpoint. */	97	/* Resolve the path to the mountpoint. */
98	rwlock_write_lock(&namespace_rwlock);	98	rwlock_write_lock(&namespace_rwlock);
99	if (rootfs.fs_handle) {	99	if (rootfs.fs_handle) {
100	/* We already have the root FS. */	100	/* We already have the root FS. */
101	if (str_cmp(mp, "/") == 0) {	101	if (str_cmp(mp, "/") == 0) {
102	/* Trying to mount root FS over root FS */	102	/* Trying to mount root FS over root FS */
103	ipc_answer_0(rid, EBUSY);	103	ipc_answer_0(rid, EBUSY);
104	rwlock_write_unlock(&namespace_rwlock);	104	rwlock_write_unlock(&namespace_rwlock);
105	return;	105	return;
106	}	106	}
107		107
108	rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);	108	rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);
109	if (rc != EOK) {	109	if (rc != EOK) {
110	/* The lookup failed for some reason. */	110	/* The lookup failed for some reason. */
111	ipc_answer_0(rid, rc);	111	ipc_answer_0(rid, rc);
112	rwlock_write_unlock(&namespace_rwlock);	112	rwlock_write_unlock(&namespace_rwlock);
113	return;	113	return;
114	}	114	}
115		115
116	mp_node = vfs_node_get(&mp_res);	116	mp_node = vfs_node_get(&mp_res);
117	if (!mp_node) {	117	if (!mp_node) {
118	ipc_answer_0(rid, ENOMEM);	118	ipc_answer_0(rid, ENOMEM);
119	rwlock_write_unlock(&namespace_rwlock);	119	rwlock_write_unlock(&namespace_rwlock);
120	return;	120	return;
121	}	121	}
122		122
123	/*	123	/*
124	* Now we hold a reference to mp_node.	124	* Now we hold a reference to mp_node.
125	* It will be dropped upon the corresponding VFS_UNMOUNT.	125	* It will be dropped upon the corresponding VFS_UNMOUNT.
126	* This prevents the mount point from being deleted.	126	* This prevents the mount point from being deleted.
127	*/	127	*/
128	} else {	128	} else {
129	/* We still don't have the root file system mounted. */	129	/* We still don't have the root file system mounted. */
130	if (str_cmp(mp, "/") == 0) {	130	if (str_cmp(mp, "/") == 0) {
131	/*	131	/*
132	* For this simple, but important case,	132	* For this simple, but important case,
133	* we are almost done.	133	* we are almost done.
134	*/	134	*/
135		135
136	/* Tell the mountee that it is being mounted. */	136	/* Tell the mountee that it is being mounted. */
137	phone = vfs_grab_phone(fs_handle);	137	phone = vfs_grab_phone(fs_handle);
138	msg = async_send_1(phone, VFS_MOUNTED,	138	msg = async_send_1(phone, VFS_MOUNTED,
139	(ipcarg_t) dev_handle, &answer);	139	(ipcarg_t) dev_handle, &answer);
140	/* send the mount options */	140	/* send the mount options */
141	rc = ipc_data_write_start(phone, (void *)opts,	141	rc = ipc_data_write_start(phone, (void *)opts,
142	str_size(opts));	142	str_size(opts));
143	if (rc != EOK) {	143	if (rc != EOK) {
144	async_wait_for(msg, NULL);	144	async_wait_for(msg, NULL);
145	vfs_release_phone(phone);	145	vfs_release_phone(phone);
146	ipc_answer_0(rid, rc);	146	ipc_answer_0(rid, rc);
147	rwlock_write_unlock(&namespace_rwlock);	147	rwlock_write_unlock(&namespace_rwlock);
148	return;	148	return;
149	}	149	}
150	async_wait_for(msg, &rc);	150	async_wait_for(msg, &rc);
151	vfs_release_phone(phone);	151	vfs_release_phone(phone);
152		152
153	if (rc != EOK) {	153	if (rc != EOK) {
154	ipc_answer_0(rid, rc);	154	ipc_answer_0(rid, rc);
155	rwlock_write_unlock(&namespace_rwlock);	155	rwlock_write_unlock(&namespace_rwlock);
156	return;	156	return;
157	}	157	}
158		158
159	rindex = (fs_index_t) IPC_GET_ARG1(answer);	159	rindex = (fs_index_t) IPC_GET_ARG1(answer);
160	rsize = (size_t) IPC_GET_ARG2(answer);	160	rsize = (size_t) IPC_GET_ARG2(answer);
161	rlnkcnt = (unsigned) IPC_GET_ARG3(answer);	161	rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
162		162
163	mr_res.triplet.fs_handle = fs_handle;	163	mr_res.triplet.fs_handle = fs_handle;
164	mr_res.triplet.dev_handle = dev_handle;	164	mr_res.triplet.dev_handle = dev_handle;
165	mr_res.triplet.index = rindex;	165	mr_res.triplet.index = rindex;
166	mr_res.size = rsize;	166	mr_res.size = rsize;
167	mr_res.lnkcnt = rlnkcnt;	167	mr_res.lnkcnt = rlnkcnt;
168	mr_res.type = VFS_NODE_DIRECTORY;	168	mr_res.type = VFS_NODE_DIRECTORY;
169		169
170	rootfs.fs_handle = fs_handle;	170	rootfs.fs_handle = fs_handle;
171	rootfs.dev_handle = dev_handle;	171	rootfs.dev_handle = dev_handle;
172		172
173	/* Add reference to the mounted root. */	173	/* Add reference to the mounted root. */
174	mr_node = vfs_node_get(&mr_res);	174	mr_node = vfs_node_get(&mr_res);
175	assert(mr_node);	175	assert(mr_node);
176		176
177	ipc_answer_0(rid, rc);	177	ipc_answer_0(rid, rc);
178	rwlock_write_unlock(&namespace_rwlock);	178	rwlock_write_unlock(&namespace_rwlock);
179	return;	179	return;
180	} else {	180	} else {
181	/*	181	/*
182	* We can't resolve this without the root filesystem	182	* We can't resolve this without the root filesystem
183	* being mounted first.	183	* being mounted first.
184	*/	184	*/
185	ipc_answer_0(rid, ENOENT);	185	ipc_answer_0(rid, ENOENT);
186	rwlock_write_unlock(&namespace_rwlock);	186	rwlock_write_unlock(&namespace_rwlock);
187	return;	187	return;
188	}	188	}
189	}	189	}
190		190
191	/*	191	/*
192	* At this point, we have all necessary pieces: file system and device	192	* At this point, we have all necessary pieces: file system and device
193	* handles, and we know the mount point VFS node.	193	* handles, and we know the mount point VFS node.
194	*/	194	*/
195		195
196	int mountee_phone = vfs_grab_phone(fs_handle);	196	int mountee_phone = vfs_grab_phone(fs_handle);
197	assert(mountee_phone >= 0);	197	assert(mountee_phone >= 0);
198	vfs_release_phone(mountee_phone);	198	vfs_release_phone(mountee_phone);
199		199
200	phone = vfs_grab_phone(mp_res.triplet.fs_handle);	200	phone = vfs_grab_phone(mp_res.triplet.fs_handle);
201	msg = async_send_4(phone, VFS_MOUNT,	201	msg = async_send_4(phone, VFS_MOUNT,
202	(ipcarg_t) mp_res.triplet.dev_handle,	202	(ipcarg_t) mp_res.triplet.dev_handle,
203	(ipcarg_t) mp_res.triplet.index,	203	(ipcarg_t) mp_res.triplet.index,
204	(ipcarg_t) fs_handle,	204	(ipcarg_t) fs_handle,
205	(ipcarg_t) dev_handle, &answer);	205	(ipcarg_t) dev_handle, &answer);
206		206
207	/* send connection */	207	/* send connection */
208	rc = async_req_1_0(phone, IPC_M_CONNECTION_CLONE, mountee_phone);	208	rc = async_req_1_0(phone, IPC_M_CONNECTION_CLONE, mountee_phone);
209	if (rc != EOK) {	209	if (rc != EOK) {
210	async_wait_for(msg, NULL);	210	async_wait_for(msg, NULL);
211	vfs_release_phone(phone);	211	vfs_release_phone(phone);
212	/* Mount failed, drop reference to mp_node. */	212	/* Mount failed, drop reference to mp_node. */
213	if (mp_node)	213	if (mp_node)
214	vfs_node_put(mp_node);	214	vfs_node_put(mp_node);
215	ipc_answer_0(rid, rc);	215	ipc_answer_0(rid, rc);
216	rwlock_write_unlock(&namespace_rwlock);	216	rwlock_write_unlock(&namespace_rwlock);
217	return;	217	return;
218	}	218	}
219		219
220	/* send the mount options */	220	/* send the mount options */
221	rc = ipc_data_write_start(phone, (void *)opts, str_size(opts));	221	rc = ipc_data_write_start(phone, (void *)opts, str_size(opts));
222	if (rc != EOK) {	222	if (rc != EOK) {
223	async_wait_for(msg, NULL);	223	async_wait_for(msg, NULL);
224	vfs_release_phone(phone);	224	vfs_release_phone(phone);
225	/* Mount failed, drop reference to mp_node. */	225	/* Mount failed, drop reference to mp_node. */
226	if (mp_node)	226	if (mp_node)
227	vfs_node_put(mp_node);	227	vfs_node_put(mp_node);
228	ipc_answer_0(rid, rc);	228	ipc_answer_0(rid, rc);
229	rwlock_write_unlock(&namespace_rwlock);	229	rwlock_write_unlock(&namespace_rwlock);
230	return;	230	return;
231	}	231	}
232	async_wait_for(msg, &rc);	232	async_wait_for(msg, &rc);
233	vfs_release_phone(phone);	233	vfs_release_phone(phone);
234		234
235	if (rc == EOK) {	235	if (rc == EOK) {
236	rindex = (fs_index_t) IPC_GET_ARG1(answer);	236	rindex = (fs_index_t) IPC_GET_ARG1(answer);
237	rsize = (size_t) IPC_GET_ARG2(answer);	237	rsize = (size_t) IPC_GET_ARG2(answer);
238	rlnkcnt = (unsigned) IPC_GET_ARG3(answer);	238	rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
239		239
240	mr_res.triplet.fs_handle = fs_handle;	240	mr_res.triplet.fs_handle = fs_handle;
241	mr_res.triplet.dev_handle = dev_handle;	241	mr_res.triplet.dev_handle = dev_handle;
242	mr_res.triplet.index = rindex;	242	mr_res.triplet.index = rindex;
243	mr_res.size = rsize;	243	mr_res.size = rsize;
244	mr_res.lnkcnt = rlnkcnt;	244	mr_res.lnkcnt = rlnkcnt;
245	mr_res.type = VFS_NODE_DIRECTORY;	245	mr_res.type = VFS_NODE_DIRECTORY;
246		246
247	/* Add reference to the mounted root. */	247	/* Add reference to the mounted root. */
248	mr_node = vfs_node_get(&mr_res);	248	mr_node = vfs_node_get(&mr_res);
249	assert(mr_node);	249	assert(mr_node);
250	} else {	250	} else {
251	/* Mount failed, drop reference to mp_node. */	251	/* Mount failed, drop reference to mp_node. */
252	if (mp_node)	252	if (mp_node)
253	vfs_node_put(mp_node);	253	vfs_node_put(mp_node);
254	}	254	}
255		255
256	ipc_answer_0(rid, rc);	256	ipc_answer_0(rid, rc);
257	rwlock_write_unlock(&namespace_rwlock);	257	rwlock_write_unlock(&namespace_rwlock);
258	}	258	}
259		259
260	/** Process pending mount requests */	260	/** Process pending mount requests */
261	void vfs_process_pending_mount(void)	261	void vfs_process_pending_mount(void)
262	{	262	{
263	link_t *cur;	263	link_t *cur;
264		264
265	loop:	265	loop:
266	for (cur = pending_req.next; cur != &pending_req; cur = cur->next) {	266	for (cur = pending_req.next; cur != &pending_req; cur = cur->next) {
267	pending_req_t *pr = list_get_instance(cur, pending_req_t, link);	267	pending_req_t *pr = list_get_instance(cur, pending_req_t, link);
268		268
269	fs_handle_t fs_handle = fs_name_to_handle(pr->fs_name, true);	269	fs_handle_t fs_handle = fs_name_to_handle(pr->fs_name, true);
270	if (!fs_handle)	270	if (!fs_handle)
271	continue;	271	continue;
272		272
273	/* Acknowledge that we know fs_name. */	273	/* Acknowledge that we know fs_name. */
274	ipc_answer_0(pr->callid, EOK);	274	ipc_answer_0(pr->callid, EOK);
275		275
276	/* Do the mount */	276	/* Do the mount */
277	vfs_mount_internal(pr->rid, pr->dev_handle, fs_handle, pr->mp,	277	vfs_mount_internal(pr->rid, pr->dev_handle, fs_handle, pr->mp,
278	pr->opts);	278	pr->opts);
279		279
280	free(pr->fs_name);	280	free(pr->fs_name);
281	free(pr->mp);	281	free(pr->mp);
282	free(pr->opts);	282	free(pr->opts);
283	list_remove(cur);	283	list_remove(cur);
284	free(pr);	284	free(pr);
285	goto loop;	285	goto loop;
286	}	286	}
287	}	287	}
288		288
289	void vfs_mount(ipc_callid_t rid, ipc_call_t *request)	289	void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
290	{	290	{
291	/*	291	/*
292	* We expect the library to do the device-name to device-handle	292	* We expect the library to do the device-name to device-handle
293	* translation for us, thus the device handle will arrive as ARG1	293	* translation for us, thus the device handle will arrive as ARG1
294	* in the request.	294	* in the request.
295	*/	295	*/
296	dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);	296	dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
297		297
298	/*	298	/*
299	* Mount flags are passed as ARG2.	299	* Mount flags are passed as ARG2.
300	*/	300	*/
301	unsigned int flags = (unsigned int) IPC_GET_ARG2(*request);	301	unsigned int flags = (unsigned int) IPC_GET_ARG2(*request);
302		302
303	/*	303	/*
304	* For now, don't make use of ARG3, but it can be used to	304	* For now, don't make use of ARG3, but it can be used to
305	* carry mount options in the future.	305	* carry mount options in the future.
306	*/	306	*/
307		307
308	/* We want the client to send us the mount point. */	308	/* We want the client to send us the mount point. */
309	ipc_callid_t callid;	309	ipc_callid_t callid;
310	size_t size;	310	size_t size;
311	if (!ipc_data_write_receive(&callid, &size)) {	311	if (!ipc_data_write_receive(&callid, &size)) {
312	ipc_answer_0(callid, EINVAL);	312	ipc_answer_0(callid, EINVAL);
313	ipc_answer_0(rid, EINVAL);	313	ipc_answer_0(rid, EINVAL);
314	return;	314	return;
315	}	315	}
316		316
317	/* Check whether size is reasonable wrt. the mount point. */	317	/* Check whether size is reasonable wrt. the mount point. */
318	if ((size < 1) \|\| (size > MAX_PATH_LEN)) {	318	if ((size < 1) \|\| (size > MAX_PATH_LEN)) {
319	ipc_answer_0(callid, EINVAL);	319	ipc_answer_0(callid, EINVAL);
320	ipc_answer_0(rid, EINVAL);	320	ipc_answer_0(rid, EINVAL);
321	return;	321	return;
322	}	322	}
323		323
324	/* Allocate buffer for the mount point data being received. */	324	/* Allocate buffer for the mount point data being received. */
325	char *mp = malloc(size + 1);	325	char *mp = malloc(size + 1);
326	if (!mp) {	326	if (!mp) {
327	ipc_answer_0(callid, ENOMEM);	327	ipc_answer_0(callid, ENOMEM);
328	ipc_answer_0(rid, ENOMEM);	328	ipc_answer_0(rid, ENOMEM);
329	return;	329	return;
330	}	330	}
331		331
332	/* Deliver the mount point. */	332	/* Deliver the mount point. */
333	ipcarg_t retval = ipc_data_write_finalize(callid, mp, size);	333	ipcarg_t retval = ipc_data_write_finalize(callid, mp, size);
334	if (retval != EOK) {	334	if (retval != EOK) {
335	ipc_answer_0(rid, retval);	335	ipc_answer_0(rid, retval);
336	free(mp);	336	free(mp);
337	return;	337	return;
338	}	338	}
339	mp[size] = '\0';	339	mp[size] = '\0';
340		340
341	/* Now we expect to receive the mount options. */	341	/* Now we expect to receive the mount options. */
342	if (!ipc_data_write_receive(&callid, &size)) {	342	if (!ipc_data_write_receive(&callid, &size)) {
343	ipc_answer_0(callid, EINVAL);	343	ipc_answer_0(callid, EINVAL);
344	ipc_answer_0(rid, EINVAL);	344	ipc_answer_0(rid, EINVAL);
345	free(mp);	345	free(mp);
346	return;	346	return;
347	}	347	}
348		348
349	/* Check the offered options size. */	349	/* Check the offered options size. */
350	if (size < 0 \|\| size > MAX_MNTOPTS_LEN) {	350	if (size < 0 \|\| size > MAX_MNTOPTS_LEN) {
351	ipc_answer_0(callid, EINVAL);	351	ipc_answer_0(callid, EINVAL);
352	ipc_answer_0(rid, EINVAL);	352	ipc_answer_0(rid, EINVAL);
353	free(mp);	353	free(mp);
354	return;	354	return;
355	}	355	}
356		356
357	/* Allocate buffer for the mount options. */	357	/* Allocate buffer for the mount options. */
358	char opts = (char ) malloc(size + 1);	358	char opts = (char ) malloc(size + 1);
359	if (!opts) {	359	if (!opts) {
360	ipc_answer_0(callid, ENOMEM);	360	ipc_answer_0(callid, ENOMEM);
361	ipc_answer_0(rid, ENOMEM);	361	ipc_answer_0(rid, ENOMEM);
362	free(mp);	362	free(mp);
363	return;	363	return;
364	}	364	}
365		365
366	/* Deliver the mount options. */	366	/* Deliver the mount options. */
367	retval = ipc_data_write_finalize(callid, opts, size);	367	retval = ipc_data_write_finalize(callid, opts, size);
368	if (retval != EOK) {	368	if (retval != EOK) {
369	ipc_answer_0(rid, retval);	369	ipc_answer_0(rid, retval);
370	free(mp);	370	free(mp);
371	free(opts);	371	free(opts);
372	return;	372	return;
373	}	373	}
374	opts[size] = '\0';	374	opts[size] = '\0';
375		375
376	/*	376	/*
377	* Now, we expect the client to send us data with the name of the file	377	* Now, we expect the client to send us data with the name of the file
378	* system.	378	* system.
379	*/	379	*/
380	if (!ipc_data_write_receive(&callid, &size)) {	380	if (!ipc_data_write_receive(&callid, &size)) {
381	ipc_answer_0(callid, EINVAL);	381	ipc_answer_0(callid, EINVAL);
382	ipc_answer_0(rid, EINVAL);	382	ipc_answer_0(rid, EINVAL);
383	free(mp);	383	free(mp);
384	free(opts);	384	free(opts);
385	return;	385	return;
386	}	386	}
387		387
388	/*	388	/*
389	* Don't receive more than is necessary for storing a full file system	389	* Don't receive more than is necessary for storing a full file system
390	* name.	390	* name.
391	*/	391	*/
392	if ((size < 1) \|\| (size > FS_NAME_MAXLEN)) {	392	if ((size < 1) \|\| (size > FS_NAME_MAXLEN)) {
393	ipc_answer_0(callid, EINVAL);	393	ipc_answer_0(callid, EINVAL);
394	ipc_answer_0(rid, EINVAL);	394	ipc_answer_0(rid, EINVAL);
395	free(mp);	395	free(mp);
396	free(opts);	396	free(opts);
397	return;	397	return;
398	}	398	}
399		399
400	/*	400	/*
401	* Allocate buffer for file system name.	401	* Allocate buffer for file system name.
402	*/	402	*/
403	char fs_name = (char ) malloc(size + 1);	403	char fs_name = (char ) malloc(size + 1);
404	if (fs_name == NULL) {	404	if (fs_name == NULL) {
405	ipc_answer_0(callid, ENOMEM);	405	ipc_answer_0(callid, ENOMEM);
406	ipc_answer_0(rid, ENOMEM);	406	ipc_answer_0(rid, ENOMEM);
407	free(mp);	407	free(mp);
408	free(opts);	408	free(opts);
409	return;	409	return;
410	}	410	}
411		411
412	/* Deliver the file system name. */	412	/* Deliver the file system name. */
413	retval = ipc_data_write_finalize(callid, fs_name, size);	413	retval = ipc_data_write_finalize(callid, fs_name, size);
414	if (retval != EOK) {	414	if (retval != EOK) {
415	ipc_answer_0(rid, retval);	415	ipc_answer_0(rid, retval);
416	free(mp);	416	free(mp);
417	free(opts);	417	free(opts);
418	free(fs_name);	418	free(fs_name);
419	return;	419	return;
420	}	420	}
421	fs_name[size] = '\0';	421	fs_name[size] = '\0';
422		422
423	/*	423	/*
424	* Wait for IPC_M_PING so that we can return an error if we don't know	424	* Wait for IPC_M_PING so that we can return an error if we don't know
425	* fs_name.	425	* fs_name.
426	*/	426	*/
427	ipc_call_t data;	427	ipc_call_t data;
428	callid = async_get_call(&data);	428	callid = async_get_call(&data);
429	if (IPC_GET_METHOD(data) != IPC_M_PING) {	429	if (IPC_GET_METHOD(data) != IPC_M_PING) {
430	ipc_answer_0(callid, ENOTSUP);	430	ipc_answer_0(callid, ENOTSUP);
431	ipc_answer_0(rid, ENOTSUP);	431	ipc_answer_0(rid, ENOTSUP);
432	free(mp);	432	free(mp);
433	free(opts);	433	free(opts);
434	free(fs_name);	434	free(fs_name);
435	return;	435	return;
436	}	436	}
437		437
438	/*	438	/*
439	* Check if we know a file system with the same name as is in fs_name.	439	* Check if we know a file system with the same name as is in fs_name.
440	* This will also give us its file system handle.	440	* This will also give us its file system handle.
441	*/	441	*/
442	fs_handle_t fs_handle = fs_name_to_handle(fs_name, true);	442	fs_handle_t fs_handle = fs_name_to_handle(fs_name, true);
443	if (!fs_handle) {	443	if (!fs_handle) {
444	if (flags & IPC_FLAG_BLOCKING) {	444	if (flags & IPC_FLAG_BLOCKING) {
445	pending_req_t *pr;	445	pending_req_t *pr;
446		446
447	/* Blocking mount, add to pending list */	447	/* Blocking mount, add to pending list */
448	pr = (pending_req_t *) malloc(sizeof(pending_req_t));	448	pr = (pending_req_t *) malloc(sizeof(pending_req_t));
449	if (!pr) {	449	if (!pr) {
450	ipc_answer_0(callid, ENOMEM);	450	ipc_answer_0(callid, ENOMEM);
451	ipc_answer_0(rid, ENOMEM);	451	ipc_answer_0(rid, ENOMEM);
452	free(mp);	452	free(mp);
453	free(fs_name);	453	free(fs_name);
454	free(opts);	454	free(opts);
455	return;	455	return;
456	}	456	}
457		457
458	pr->fs_name = fs_name;	458	pr->fs_name = fs_name;
459	pr->mp = mp;	459	pr->mp = mp;
460	pr->opts = opts;	460	pr->opts = opts;
461	pr->callid = callid;	461	pr->callid = callid;
462	pr->rid = rid;	462	pr->rid = rid;
463	pr->dev_handle = dev_handle;	463	pr->dev_handle = dev_handle;
464	link_initialize(&pr->link);	464	link_initialize(&pr->link);
465	list_append(&pr->link, &pending_req);	465	list_append(&pr->link, &pending_req);
466	return;	466	return;
467	}	467	}
468		468
469	ipc_answer_0(callid, ENOENT);	469	ipc_answer_0(callid, ENOENT);
470	ipc_answer_0(rid, ENOENT);	470	ipc_answer_0(rid, ENOENT);
471	free(mp);	471	free(mp);
472	free(fs_name);	472	free(fs_name);
473	free(opts);	473	free(opts);
474	return;	474	return;
475	}	475	}
476		476
477	/* Acknowledge that we know fs_name. */	477	/* Acknowledge that we know fs_name. */
478	ipc_answer_0(callid, EOK);	478	ipc_answer_0(callid, EOK);
479		479
480	/* Do the mount */	480	/* Do the mount */
481	vfs_mount_internal(rid, dev_handle, fs_handle, mp, opts);	481	vfs_mount_internal(rid, dev_handle, fs_handle, mp, opts);
482	free(mp);	482	free(mp);
483	free(fs_name);	483	free(fs_name);
484	free(opts);	484	free(opts);
485	}	485	}
486		486
487	void vfs_open(ipc_callid_t rid, ipc_call_t *request)	487	void vfs_open(ipc_callid_t rid, ipc_call_t *request)
488	{	488	{
489	async_serialize_start();	-
490		-
491	if (!vfs_files_init()) {	489	if (!vfs_files_init()) {
492	ipc_answer_0(rid, ENOMEM);	490	ipc_answer_0(rid, ENOMEM);
493	async_serialize_end();	-
494	return;	491	return;
495	}	492	}
496		493
497	/*	494	/*
498	* The POSIX interface is open(path, oflag, mode).	495	* The POSIX interface is open(path, oflag, mode).
499	* We can receive oflags and mode along with the VFS_OPEN call; the path	496	* We can receive oflags and mode along with the VFS_OPEN call; the path
500	* will need to arrive in another call.	497	* will need to arrive in another call.

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/vfs/vfs_ops.c @ 3795 – Rev 4443 → 4445