Rev 4443 | Rev 4463 | Go to most recent revision | Blame | Compare with Previous | Last modification | View Log | Download | RSS feed
/*
* 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);
}
/**
* @}
*/