0,0 → 1,868 |
/* |
* 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_triplet_t rootfs = { |
.fs_handle = 0, |
.dev_handle = 0, |
.index = 0, |
}; |
|
static int |
lookup_root(fs_handle_t fs_handle, dev_handle_t dev_handle, |
vfs_lookup_res_t *result) |
{ |
vfs_pair_t altroot = { |
.fs_handle = fs_handle, |
.dev_handle = dev_handle, |
}; |
|
return vfs_lookup_internal("/", L_DIRECTORY, result, &altroot); |
} |
|
void vfs_mount(ipc_callid_t rid, ipc_call_t *request) |
{ |
dev_handle_t dev_handle; |
vfs_node_t *mp_node = NULL; |
|
/* |
* 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. |
*/ |
|
ipc_callid_t callid; |
size_t size; |
|
/* |
* 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'; |
|
/* |
* 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(rid, ENOENT); |
return; |
} |
|
/* 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'; |
|
/* |
* Lookup the root node of the filesystem being mounted. |
* In this case, we don't need to take the namespace_futex as the root |
* node cannot be removed. However, we do take a reference to it so |
* that we can track how many times it has been mounted. |
*/ |
int rc; |
vfs_lookup_res_t mr_res; |
rc = lookup_root(fs_handle, dev_handle, &mr_res); |
if (rc != EOK) { |
free(buf); |
ipc_answer_0(rid, rc); |
return; |
} |
vfs_node_t *mr_node = vfs_node_get(&mr_res); |
if (!mr_node) { |
free(buf); |
ipc_answer_0(rid, ENOMEM); |
return; |
} |
|
/* Finally, we need to 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); |
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); |
vfs_node_put(mr_node); /* failed -> drop reference */ |
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); |
vfs_node_put(mr_node); /* failed -> drop reference */ |
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] == '/')) { |
/* For this simple, but important case, we are done. */ |
rootfs = mr_res.triplet; |
futex_up(&rootfs_futex); |
free(buf); |
ipc_answer_0(rid, EOK); |
return; |
} else { |
/* |
* We can't resolve this without the root filesystem |
* being mounted first. |
*/ |
futex_up(&rootfs_futex); |
free(buf); |
vfs_node_put(mr_node); /* failed -> drop reference */ |
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 and also the root node |
* of the file system being mounted. |
*/ |
|
int phone = vfs_grab_phone(mp_res.triplet.fs_handle); |
/* Later we can use ARG3 to pass mode/flags. */ |
aid_t req1 = async_send_3(phone, VFS_MOUNT, |
(ipcarg_t) mp_res.triplet.dev_handle, |
(ipcarg_t) mp_res.triplet.index, 0, NULL); |
/* The second call uses the same method. */ |
aid_t req2 = async_send_3(phone, VFS_MOUNT, |
(ipcarg_t) mr_res.triplet.fs_handle, |
(ipcarg_t) mr_res.triplet.dev_handle, |
(ipcarg_t) mr_res.triplet.index, NULL); |
vfs_release_phone(phone); |
|
ipcarg_t rc1; |
ipcarg_t rc2; |
async_wait_for(req1, &rc1); |
async_wait_for(req2, &rc2); |
|
if ((rc1 != EOK) || (rc2 != EOK)) { |
/* Mount failed, drop references to mr_node and mp_node. */ |
vfs_node_put(mr_node); |
if (mp_node) |
vfs_node_put(mp_node); |
} |
|
if (rc2 == EOK) |
ipc_answer_0(rid, rc1); |
else if (rc1 == EOK) |
ipc_answer_0(rid, rc2); |
else |
ipc_answer_0(rid, rc1); |
} |
|
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); |
if (fd >= MAX_OPEN_FILES) { |
ipc_answer_0(rid, EBADF); |
return; |
} |
vfs_fd_free(fd); |
ipc_answer_0(rid, EOK); |
} |
|
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); |
} |
|
/** |
* @} |
*/ |