| 0,0 → 1,870 |
|---|
| /* |
| * 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); |
| |
| /** |
| * 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 |
| }; |
| |
| void vfs_mount(ipc_callid_t rid, ipc_call_t *request) |
| { |
| dev_handle_t dev_handle; |
| vfs_node_t *mp_node = NULL; |
| ipc_callid_t callid; |
| ipc_call_t data; |
| int rc; |
| int phone; |
| size_t size; |
| |
| /* |
| * 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 = (dev_handle_t)IPC_GET_ARG1(*request); |
| |
| /* |
| * For now, don't make use of ARG2 and ARG3, but they can be used to |
| * carry mount options in the future. |
| */ |
| |
| /* |
| * 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); |
| 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); |
| return; |
| } |
| |
| /* Deliver the file system name. */ |
| char fs_name[FS_NAME_MAXLEN + 1]; |
| (void) ipc_data_write_finalize(callid, fs_name, size); |
| fs_name[size] = '\0'; |
| |
| /* |
| * Wait for IPC_M_PING so that we can return an error if we don't know |
| * fs_name. |
| */ |
| callid = async_get_call(&data); |
| if (IPC_GET_METHOD(data) != IPC_M_PING) { |
| ipc_answer_0(callid, ENOTSUP); |
| ipc_answer_0(rid, ENOTSUP); |
| 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) { |
| ipc_answer_0(callid, ENOENT); |
| ipc_answer_0(rid, ENOENT); |
| return; |
| } |
| |
| /* Acknowledge that we know fs_name. */ |
| ipc_answer_0(callid, EOK); |
| |
| /* Now, we want the client to send us the mount point. */ |
| 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. */ |
| uint8_t *buf; |
| buf = malloc(size + 1); |
| if (!buf) { |
| ipc_answer_0(callid, ENOMEM); |
| ipc_answer_0(rid, ENOMEM); |
| return; |
| } |
| |
| /* Deliver the mount point. */ |
| (void) ipc_data_write_finalize(callid, buf, size); |
| buf[size] = '\0'; |
| |
| /* Resolve the path to the mountpoint. */ |
| vfs_lookup_res_t mp_res; |
| futex_down(&rootfs_futex); |
| if (rootfs.fs_handle) { |
| /* We already have the root FS. */ |
| rwlock_write_lock(&namespace_rwlock); |
| if ((size == 1) && (buf[0] == '/')) { |
| /* Trying to mount root FS over root FS */ |
| rwlock_write_unlock(&namespace_rwlock); |
| futex_up(&rootfs_futex); |
| free(buf); |
| ipc_answer_0(rid, EBUSY); |
| return; |
| } |
| rc = vfs_lookup_internal(buf, L_DIRECTORY, &mp_res, NULL); |
| if (rc != EOK) { |
| /* The lookup failed for some reason. */ |
| rwlock_write_unlock(&namespace_rwlock); |
| futex_up(&rootfs_futex); |
| free(buf); |
| 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); |
| free(buf); |
| 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 ((size == 1) && (buf[0] == '/')) { |
| vfs_lookup_res_t mr_res; |
| vfs_node_t *mr_node; |
| ipcarg_t rindex; |
| ipcarg_t rsize; |
| ipcarg_t rlnkcnt; |
| |
| /* |
| * For this simple, but important case, |
| * we are almost done. |
| */ |
| free(buf); |
| |
| /* Tell the mountee that it is being mounted. */ |
| phone = vfs_grab_phone(fs_handle); |
| rc = async_req_1_3(phone, VFS_MOUNTED, |
| (ipcarg_t) dev_handle, &rindex, &rsize, &rlnkcnt); |
| vfs_release_phone(phone); |
| |
| if (rc != EOK) { |
| futex_up(&rootfs_futex); |
| ipc_answer_0(rid, rc); |
| return; |
| } |
| |
| mr_res.triplet.fs_handle = fs_handle; |
| mr_res.triplet.dev_handle = dev_handle; |
| mr_res.triplet.index = (fs_index_t) rindex; |
| mr_res.size = (size_t) rsize; |
| mr_res.lnkcnt = (unsigned) rlnkcnt; |
| |
| 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); |
| free(buf); |
| ipc_answer_0(rid, ENOENT); |
| return; |
| } |
| } |
| futex_up(&rootfs_futex); |
| |
| free(buf); /* The buffer is not needed anymore. */ |
| |
| /* |
| * At this point, we have all necessary pieces: file system and device |
| * handles, and we know the mount point VFS node. |
| */ |
| |
| phone = vfs_grab_phone(mp_res.triplet.fs_handle); |
| rc = async_req_4_0(phone, VFS_MOUNT, |
| (ipcarg_t) mp_res.triplet.dev_handle, |
| (ipcarg_t) mp_res.triplet.index, |
| (ipcarg_t) fs_handle, |
| (ipcarg_t) dev_handle); |
| vfs_release_phone(phone); |
| |
| if (rc != EOK) { |
| /* Mount failed, drop reference to mp_node. */ |
| if (mp_node) |
| vfs_node_put(mp_node); |
| } |
| |
| ipc_answer_0(rid, rc); |
| } |
| |
| 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; |
| |
| 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); |
| |
| 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); |
| |
| /* 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 len; |
| ipc_callid_t callid; |
| int rc; |
| |
| /* Retrieve the old path. */ |
| if (!ipc_data_write_receive(&callid, &len)) { |
| ipc_answer_0(callid, EINVAL); |
| ipc_answer_0(rid, EINVAL); |
| return; |
| } |
| char *old = malloc(len + 1); |
| if (!old) { |
| ipc_answer_0(callid, ENOMEM); |
| ipc_answer_0(rid, ENOMEM); |
| return; |
| } |
| if ((rc = ipc_data_write_finalize(callid, old, len))) { |
| ipc_answer_0(rid, rc); |
| free(old); |
| return; |
| } |
| old[len] = '\0'; |
| |
| /* Retrieve the new path. */ |
| if (!ipc_data_write_receive(&callid, &len)) { |
| ipc_answer_0(callid, EINVAL); |
| ipc_answer_0(rid, EINVAL); |
| free(old); |
| return; |
| } |
| char *new = malloc(len + 1); |
| if (!new) { |
| ipc_answer_0(callid, ENOMEM); |
| ipc_answer_0(rid, ENOMEM); |
| free(old); |
| return; |
| } |
| if ((rc = ipc_data_write_finalize(callid, new, len))) { |
| ipc_answer_0(rid, rc); |
| free(old); |
| free(new); |
| return; |
| } |
| new[len] = '\0'; |
| |
| char *oldc = canonify(old, &len); |
| char *newc = canonify(new, NULL); |
| if (!oldc || !newc) { |
| ipc_answer_0(rid, EINVAL); |
| free(old); |
| free(new); |
| return; |
| } |
| if (!strncmp(newc, oldc, len)) { |
| /* oldc is a prefix of newc */ |
| ipc_answer_0(rid, EINVAL); |
| free(old); |
| free(new); |
| return; |
| } |
| |
| vfs_lookup_res_t old_lr; |
| vfs_lookup_res_t new_lr; |
| vfs_lookup_res_t new_par_lr; |
| rwlock_write_lock(&namespace_rwlock); |
| /* Lookup the node belonging to the old file name. */ |
| rc = vfs_lookup_internal(oldc, L_NONE, &old_lr, NULL); |
| if (rc != EOK) { |
| rwlock_write_unlock(&namespace_rwlock); |
| ipc_answer_0(rid, rc); |
| free(old); |
| free(new); |
| return; |
| } |
| vfs_node_t *old_node = vfs_node_get(&old_lr); |
| if (!old_node) { |
| rwlock_write_unlock(&namespace_rwlock); |
| ipc_answer_0(rid, ENOMEM); |
| free(old); |
| free(new); |
| return; |
| } |
| /* Lookup parent of the new file name. */ |
| rc = vfs_lookup_internal(newc, L_PARENT, &new_par_lr, NULL); |
| if (rc != EOK) { |
| rwlock_write_unlock(&namespace_rwlock); |
| ipc_answer_0(rid, rc); |
| free(old); |
| free(new); |
| return; |
| } |
| /* Check whether linking to the same file system instance. */ |
| if ((old_node->fs_handle != new_par_lr.triplet.fs_handle) || |
| (old_node->dev_handle != new_par_lr.triplet.dev_handle)) { |
| rwlock_write_unlock(&namespace_rwlock); |
| ipc_answer_0(rid, EXDEV); /* different file systems */ |
| free(old); |
| free(new); |
| return; |
| } |
| /* Destroy the old link for the new name. */ |
| vfs_node_t *new_node = NULL; |
| rc = vfs_lookup_internal(newc, L_UNLINK, &new_lr, NULL); |
| switch (rc) { |
| case ENOENT: |
| /* simply not in our way */ |
| break; |
| case EOK: |
| new_node = vfs_node_get(&new_lr); |
| if (!new_node) { |
| rwlock_write_unlock(&namespace_rwlock); |
| ipc_answer_0(rid, ENOMEM); |
| free(old); |
| free(new); |
| return; |
| } |
| futex_down(&nodes_futex); |
| new_node->lnkcnt--; |
| futex_up(&nodes_futex); |
| break; |
| default: |
| rwlock_write_unlock(&namespace_rwlock); |
| ipc_answer_0(rid, ENOTEMPTY); |
| free(old); |
| free(new); |
| return; |
| } |
| /* Create the new link for the new name. */ |
| rc = vfs_lookup_internal(newc, L_LINK, NULL, NULL, old_node->index); |
| if (rc != EOK) { |
| rwlock_write_unlock(&namespace_rwlock); |
| if (new_node) |
| vfs_node_put(new_node); |
| ipc_answer_0(rid, rc); |
| free(old); |
| free(new); |
| return; |
| } |
| futex_down(&nodes_futex); |
| old_node->lnkcnt++; |
| futex_up(&nodes_futex); |
| /* Destroy the link for the old name. */ |
| rc = vfs_lookup_internal(oldc, L_UNLINK, NULL, NULL); |
| if (rc != EOK) { |
| rwlock_write_unlock(&namespace_rwlock); |
| vfs_node_put(old_node); |
| if (new_node) |
| vfs_node_put(new_node); |
| ipc_answer_0(rid, rc); |
| free(old); |
| free(new); |
| return; |
| } |
| futex_down(&nodes_futex); |
| old_node->lnkcnt--; |
| futex_up(&nodes_futex); |
| rwlock_write_unlock(&namespace_rwlock); |
| vfs_node_put(old_node); |
| if (new_node) |
| vfs_node_put(new_node); |
| free(old); |
| free(new); |
| ipc_answer_0(rid, EOK); |
| } |
| |
| /** |
| * @} |
| */ |