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2689 jermar 1
/*
2
 * Copyright (c) 2008 Jakub Jermar
3
 * All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
11
 * - Redistributions in binary form must reproduce the above copyright
12
 *   notice, this list of conditions and the following disclaimer in the
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
15
 *   derived from this software without specific prior written permission.
16
 *
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
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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
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
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 */
28
 
29
/** @addtogroup fs
30
 * @{
31
 */
32
 
33
/**
34
 * @file    vfs_ops.c
35
 * @brief   Operations that VFS offers to its clients.
36
 */
37
 
2763 jermar 38
#include "vfs.h"
2689 jermar 39
#include <ipc/ipc.h>
40
#include <async.h>
41
#include <errno.h>
42
#include <stdio.h>
43
#include <stdlib.h>
44
#include <string.h>
45
#include <bool.h>
46
#include <futex.h>
47
#include <rwlock.h>
48
#include <libadt/list.h>
49
#include <unistd.h>
50
#include <ctype.h>
2708 jermar 51
#include <fcntl.h>
2689 jermar 52
#include <assert.h>
2763 jermar 53
#include <vfs/canonify.h>
2689 jermar 54
 
2748 jermar 55
/* Forward declarations of static functions. */
2770 jermar 56
static int vfs_truncate_internal(fs_handle_t, dev_handle_t, fs_index_t, size_t);
2748 jermar 57
 
2689 jermar 58
/**
59
 * This rwlock prevents the race between a triplet-to-VFS-node resolution and a
60
 * concurrent VFS operation which modifies the file system namespace.
61
 */
62
RWLOCK_INITIALIZE(namespace_rwlock);
63
 
2766 jermar 64
futex_t rootfs_futex = FUTEX_INITIALIZER;
3153 svoboda 65
vfs_pair_t rootfs = {
2689 jermar 66
    .fs_handle = 0,
3153 svoboda 67
    .dev_handle = 0
2689 jermar 68
};
69
 
70
void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
71
{
2770 jermar 72
    dev_handle_t dev_handle;
2689 jermar 73
    vfs_node_t *mp_node = NULL;
3009 svoboda 74
    int rc;
75
    int phone;
2689 jermar 76
 
77
    /*
78
     * We expect the library to do the device-name to device-handle
79
     * translation for us, thus the device handle will arrive as ARG1
80
     * in the request.
81
     */
2770 jermar 82
    dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
2689 jermar 83
 
84
    /*
85
     * For now, don't make use of ARG2 and ARG3, but they can be used to
86
     * carry mount options in the future.
87
     */
88
 
89
    ipc_callid_t callid;
90
    size_t size;
91
 
92
    /*
93
     * Now, we expect the client to send us data with the name of the file
94
     * system.
95
     */
96
    if (!ipc_data_write_receive(&callid, &size)) {
97
        ipc_answer_0(callid, EINVAL);
98
        ipc_answer_0(rid, EINVAL);
99
        return;
100
    }
101
 
102
    /*
103
     * Don't receive more than is necessary for storing a full file system
104
     * name.
105
     */
106
    if (size < 1 || size > FS_NAME_MAXLEN) {
107
        ipc_answer_0(callid, EINVAL);
108
        ipc_answer_0(rid, EINVAL);
109
        return;
110
    }
111
 
2707 jermar 112
    /* Deliver the file system name. */
2689 jermar 113
    char fs_name[FS_NAME_MAXLEN + 1];
114
    (void) ipc_data_write_finalize(callid, fs_name, size);
115
    fs_name[size] = '\0';
116
 
117
    /*
118
     * Check if we know a file system with the same name as is in fs_name.
119
     * This will also give us its file system handle.
120
     */
2770 jermar 121
    fs_handle_t fs_handle = fs_name_to_handle(fs_name, true);
2689 jermar 122
    if (!fs_handle) {
123
        ipc_answer_0(rid, ENOENT);
124
        return;
125
    }
126
 
2707 jermar 127
    /* Now, we want the client to send us the mount point. */
2689 jermar 128
    if (!ipc_data_write_receive(&callid, &size)) {
129
        ipc_answer_0(callid, EINVAL);
130
        ipc_answer_0(rid, EINVAL);
131
        return;
132
    }
133
 
2707 jermar 134
    /* Check whether size is reasonable wrt. the mount point. */
2689 jermar 135
    if (size < 1 || size > MAX_PATH_LEN) {
136
        ipc_answer_0(callid, EINVAL);
137
        ipc_answer_0(rid, EINVAL);
138
        return;
139
    }
2707 jermar 140
    /* Allocate buffer for the mount point data being received. */
2689 jermar 141
    uint8_t *buf;
2752 jermar 142
    buf = malloc(size + 1);
2689 jermar 143
    if (!buf) {
144
        ipc_answer_0(callid, ENOMEM);
145
        ipc_answer_0(rid, ENOMEM);
146
        return;
147
    }
148
 
2707 jermar 149
    /* Deliver the mount point. */
2689 jermar 150
    (void) ipc_data_write_finalize(callid, buf, size);
2752 jermar 151
    buf[size] = '\0';
2689 jermar 152
 
3153 svoboda 153
    /* Resolve the path to the mountpoint. */
2691 jermar 154
    vfs_lookup_res_t mp_res;
2689 jermar 155
    futex_down(&rootfs_futex);
156
    if (rootfs.fs_handle) {
2707 jermar 157
        /* We already have the root FS. */
2689 jermar 158
        rwlock_write_lock(&namespace_rwlock);
2788 jermar 159
        if ((size == 1) && (buf[0] == '/')) {
160
            /* Trying to mount root FS over root FS */
161
            rwlock_write_unlock(&namespace_rwlock);
162
            futex_up(&rootfs_futex);
163
            free(buf);
164
            ipc_answer_0(rid, EBUSY);
165
            return;
166
        }
2752 jermar 167
        rc = vfs_lookup_internal(buf, L_DIRECTORY, &mp_res, NULL);
2689 jermar 168
        if (rc != EOK) {
2707 jermar 169
            /* The lookup failed for some reason. */
2689 jermar 170
            rwlock_write_unlock(&namespace_rwlock);
171
            futex_up(&rootfs_futex);
172
            free(buf);
173
            ipc_answer_0(rid, rc);
174
            return;
175
        }
2691 jermar 176
        mp_node = vfs_node_get(&mp_res);
2689 jermar 177
        if (!mp_node) {
178
            rwlock_write_unlock(&namespace_rwlock);
179
            futex_up(&rootfs_futex);
180
            free(buf);
181
            ipc_answer_0(rid, ENOMEM);
182
            return;
183
        }
184
        /*
185
         * Now we hold a reference to mp_node.
186
         * It will be dropped upon the corresponding VFS_UNMOUNT.
187
         * This prevents the mount point from being deleted.
188
         */
189
        rwlock_write_unlock(&namespace_rwlock);
190
    } else {
2707 jermar 191
        /* We still don't have the root file system mounted. */
2689 jermar 192
        if ((size == 1) && (buf[0] == '/')) {
3009 svoboda 193
            /*
194
             * For this simple, but important case,
195
             * we are almost done.
196
             */
197
            free(buf);
198
 
3153 svoboda 199
            /* Tell the mountee that it is being mounted. */
200
            phone = vfs_grab_phone(fs_handle);
201
            rc = async_req_1_0(phone, VFS_MOUNTED,
202
                (ipcarg_t) dev_handle);
3009 svoboda 203
            vfs_release_phone(phone);
204
 
3153 svoboda 205
            if (rc == EOK) {
206
                rootfs.fs_handle = fs_handle;
207
                rootfs.dev_handle = dev_handle;
208
            }
3009 svoboda 209
 
2689 jermar 210
            futex_up(&rootfs_futex);
3009 svoboda 211
            ipc_answer_0(rid, rc);
2689 jermar 212
            return;
213
        } else {
214
            /*
215
             * We can't resolve this without the root filesystem
216
             * being mounted first.
217
             */
218
            futex_up(&rootfs_futex);
219
            free(buf);
220
            ipc_answer_0(rid, ENOENT);
221
            return;
222
        }
223
    }
224
    futex_up(&rootfs_futex);
225
 
226
    free(buf);  /* The buffer is not needed anymore. */
227
 
228
    /*
229
     * At this point, we have all necessary pieces: file system and device
3153 svoboda 230
     * handles, and we know the mount point VFS node.
2689 jermar 231
     */
232
 
3009 svoboda 233
    phone = vfs_grab_phone(mp_res.triplet.fs_handle);
3153 svoboda 234
    rc = async_req_4_0(phone, VFS_MOUNT,
2691 jermar 235
        (ipcarg_t) mp_res.triplet.dev_handle,
3009 svoboda 236
        (ipcarg_t) mp_res.triplet.index,
3153 svoboda 237
        (ipcarg_t) fs_handle,
238
        (ipcarg_t) dev_handle);
2689 jermar 239
    vfs_release_phone(phone);
240
 
3009 svoboda 241
    if (rc != EOK) {
3153 svoboda 242
        /* Mount failed, drop reference to mp_node. */
2689 jermar 243
        if (mp_node)
244
            vfs_node_put(mp_node);
245
    }
246
 
3009 svoboda 247
    ipc_answer_0(rid, rc);
2689 jermar 248
}
249
 
250
void vfs_open(ipc_callid_t rid, ipc_call_t *request)
251
{
252
    if (!vfs_files_init()) {
253
        ipc_answer_0(rid, ENOMEM);
254
        return;
255
    }
256
 
257
    /*
2700 jermar 258
     * The POSIX interface is open(path, oflag, mode).
259
     * We can receive oflags and mode along with the VFS_OPEN call; the path
2689 jermar 260
     * will need to arrive in another call.
2700 jermar 261
     *
262
     * We also receive one private, non-POSIX set of flags called lflag
263
     * used to pass information to vfs_lookup_internal().
2689 jermar 264
     */
2700 jermar 265
    int lflag = IPC_GET_ARG1(*request);
266
    int oflag = IPC_GET_ARG2(*request);
267
    int mode = IPC_GET_ARG3(*request);
2689 jermar 268
    size_t len;
269
 
2708 jermar 270
    if (oflag & O_CREAT)
271
        lflag |= L_CREATE;
272
    if (oflag & O_EXCL)
273
        lflag |= L_EXCLUSIVE;
274
 
2689 jermar 275
    ipc_callid_t callid;
276
 
277
    if (!ipc_data_write_receive(&callid, &len)) {
278
        ipc_answer_0(callid, EINVAL);
279
        ipc_answer_0(rid, EINVAL);
280
        return;
281
    }
2752 jermar 282
    char *path = malloc(len + 1);
2689 jermar 283
    if (!path) {
284
        ipc_answer_0(callid, ENOMEM);
285
        ipc_answer_0(rid, ENOMEM);
286
        return;
287
    }
288
    int rc;
289
    if ((rc = ipc_data_write_finalize(callid, path, len))) {
290
        ipc_answer_0(rid, rc);
291
        free(path);
292
        return;
293
    }
2752 jermar 294
    path[len] = '\0';
2689 jermar 295
 
296
    /*
297
     * Avoid the race condition in which the file can be deleted before we
298
     * find/create-and-lock the VFS node corresponding to the looked-up
299
     * triplet.
300
     */
2708 jermar 301
    if (lflag & L_CREATE)
302
        rwlock_write_lock(&namespace_rwlock);
303
    else
304
        rwlock_read_lock(&namespace_rwlock);
2689 jermar 305
 
2707 jermar 306
    /* The path is now populated and we can call vfs_lookup_internal(). */
2691 jermar 307
    vfs_lookup_res_t lr;
2752 jermar 308
    rc = vfs_lookup_internal(path, lflag, &lr, NULL);
2689 jermar 309
    if (rc) {
2708 jermar 310
        if (lflag & L_CREATE)
311
            rwlock_write_unlock(&namespace_rwlock);
312
        else
313
            rwlock_read_unlock(&namespace_rwlock);
2689 jermar 314
        ipc_answer_0(rid, rc);
315
        free(path);
316
        return;
317
    }
318
 
2748 jermar 319
    /* Path is no longer needed. */
2689 jermar 320
    free(path);
321
 
2691 jermar 322
    vfs_node_t *node = vfs_node_get(&lr);
2708 jermar 323
    if (lflag & L_CREATE)
324
        rwlock_write_unlock(&namespace_rwlock);
325
    else
326
        rwlock_read_unlock(&namespace_rwlock);
2689 jermar 327
 
2748 jermar 328
    /* Truncate the file if requested and if necessary. */
329
    if (oflag & O_TRUNC) {
2749 jermar 330
        rwlock_write_lock(&node->contents_rwlock);
2748 jermar 331
        if (node->size) {
332
            rc = vfs_truncate_internal(node->fs_handle,
333
                node->dev_handle, node->index, 0);
334
            if (rc) {
2749 jermar 335
                rwlock_write_unlock(&node->contents_rwlock);
2748 jermar 336
                vfs_node_put(node);
337
                ipc_answer_0(rid, rc);
338
                return;
339
            }
340
            node->size = 0;
341
        }
2749 jermar 342
        rwlock_write_unlock(&node->contents_rwlock);
2748 jermar 343
    }
344
 
2689 jermar 345
    /*
346
     * Get ourselves a file descriptor and the corresponding vfs_file_t
347
     * structure.
348
     */
349
    int fd = vfs_fd_alloc();
350
    if (fd < 0) {
351
        vfs_node_put(node);
352
        ipc_answer_0(rid, fd);
353
        return;
354
    }
355
    vfs_file_t *file = vfs_file_get(fd);
356
    file->node = node;
2710 jermar 357
    if (oflag & O_APPEND)
2709 jermar 358
        file->append = true;
2689 jermar 359
 
360
    /*
361
     * The following increase in reference count is for the fact that the
362
     * file is being opened and that a file structure is pointing to it.
363
     * It is necessary so that the file will not disappear when
364
     * vfs_node_put() is called. The reference will be dropped by the
365
     * respective VFS_CLOSE.
366
     */
367
    vfs_node_addref(node);
368
    vfs_node_put(node);
369
 
2707 jermar 370
    /* Success! Return the new file descriptor to the client. */
2689 jermar 371
    ipc_answer_1(rid, EOK, fd);
372
}
373
 
2734 jermar 374
void vfs_close(ipc_callid_t rid, ipc_call_t *request)
375
{
376
    int fd = IPC_GET_ARG1(*request);
377
    if (fd >= MAX_OPEN_FILES) {
378
        ipc_answer_0(rid, EBADF);
379
        return;
380
    }
381
    vfs_fd_free(fd);
382
    ipc_answer_0(rid, EOK);
383
}
384
 
2689 jermar 385
static void vfs_rdwr(ipc_callid_t rid, ipc_call_t *request, bool read)
386
{
387
 
388
    /*
389
     * The following code strongly depends on the fact that the files data
390
     * structure can be only accessed by a single fibril and all file
391
     * operations are serialized (i.e. the reads and writes cannot
392
     * interleave and a file cannot be closed while it is being read).
393
     *
394
     * Additional synchronization needs to be added once the table of
395
     * open files supports parallel access!
396
     */
397
 
398
    int fd = IPC_GET_ARG1(*request);
3150 svoboda 399
 
2707 jermar 400
    /* Lookup the file structure corresponding to the file descriptor. */
2689 jermar 401
    vfs_file_t *file = vfs_file_get(fd);
402
    if (!file) {
403
        ipc_answer_0(rid, ENOENT);
404
        return;
405
    }
3150 svoboda 406
 
2689 jermar 407
    /*
408
     * Now we need to receive a call with client's
409
     * IPC_M_DATA_READ/IPC_M_DATA_WRITE request.
410
     */
411
    ipc_callid_t callid;
412
    int res;
413
    if (read)
414
        res = ipc_data_read_receive(&callid, NULL);
415
    else
416
        res = ipc_data_write_receive(&callid, NULL);
417
    if (!res) {
418
        ipc_answer_0(callid, EINVAL);
419
        ipc_answer_0(rid, EINVAL);
420
        return;
421
    }
3150 svoboda 422
 
2689 jermar 423
    /*
424
     * Lock the open file structure so that no other thread can manipulate
425
     * the same open file at a time.
426
     */
427
    futex_down(&file->lock);
3150 svoboda 428
 
2689 jermar 429
    /*
430
     * Lock the file's node so that no other client can read/write to it at
431
     * the same time.
432
     */
433
    if (read)
434
        rwlock_read_lock(&file->node->contents_rwlock);
435
    else
436
        rwlock_write_lock(&file->node->contents_rwlock);
3150 svoboda 437
 
2689 jermar 438
    int fs_phone = vfs_grab_phone(file->node->fs_handle);  
439
 
2707 jermar 440
    /* Make a VFS_READ/VFS_WRITE request at the destination FS server. */
2689 jermar 441
    aid_t msg;
442
    ipc_call_t answer;
2709 jermar 443
    if (!read && file->append)
444
        file->pos = file->node->size;
2689 jermar 445
    msg = async_send_3(fs_phone, IPC_GET_METHOD(*request),
446
        file->node->dev_handle, file->node->index, file->pos, &answer);
447
 
448
    /*
449
     * Forward the IPC_M_DATA_READ/IPC_M_DATA_WRITE request to the
450
     * destination FS server. The call will be routed as if sent by
451
     * ourselves. Note that call arguments are immutable in this case so we
452
     * don't have to bother.
453
     */
454
    ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
3150 svoboda 455
 
2689 jermar 456
    vfs_release_phone(fs_phone);
3150 svoboda 457
 
2707 jermar 458
    /* Wait for reply from the FS server. */
2689 jermar 459
    ipcarg_t rc;
460
    async_wait_for(msg, &rc);
461
    size_t bytes = IPC_GET_ARG1(answer);
3150 svoboda 462
 
2707 jermar 463
    /* Unlock the VFS node. */
2689 jermar 464
    if (read)
465
        rwlock_read_unlock(&file->node->contents_rwlock);
466
    else {
467
        /* Update the cached version of node's size. */
2710 jermar 468
        if (rc == EOK)
469
            file->node->size = IPC_GET_ARG2(answer);
2689 jermar 470
        rwlock_write_unlock(&file->node->contents_rwlock);
471
    }
3150 svoboda 472
 
2707 jermar 473
    /* Update the position pointer and unlock the open file. */
2710 jermar 474
    if (rc == EOK)
475
        file->pos += bytes;
2689 jermar 476
    futex_up(&file->lock);
3150 svoboda 477
 
2689 jermar 478
    /*
479
     * FS server's reply is the final result of the whole operation we
480
     * return to the client.
481
     */
482
    ipc_answer_1(rid, rc, bytes);
483
}
484
 
485
void vfs_read(ipc_callid_t rid, ipc_call_t *request)
486
{
487
    vfs_rdwr(rid, request, true);
488
}
489
 
490
void vfs_write(ipc_callid_t rid, ipc_call_t *request)
491
{
492
    vfs_rdwr(rid, request, false);
493
}
494
 
495
void vfs_seek(ipc_callid_t rid, ipc_call_t *request)
496
{
497
    int fd = (int) IPC_GET_ARG1(*request);
498
    off_t off = (off_t) IPC_GET_ARG2(*request);
499
    int whence = (int) IPC_GET_ARG3(*request);
500
 
501
 
2707 jermar 502
    /* Lookup the file structure corresponding to the file descriptor. */
2689 jermar 503
    vfs_file_t *file = vfs_file_get(fd);
504
    if (!file) {
505
        ipc_answer_0(rid, ENOENT);
506
        return;
507
    }
508
 
509
    off_t newpos;
510
    futex_down(&file->lock);
511
    if (whence == SEEK_SET) {
512
        file->pos = off;
513
        futex_up(&file->lock);
514
        ipc_answer_1(rid, EOK, off);
515
        return;
516
    }
517
    if (whence == SEEK_CUR) {
518
        if (file->pos + off < file->pos) {
519
            futex_up(&file->lock);
520
            ipc_answer_0(rid, EOVERFLOW);
521
            return;
522
        }
523
        file->pos += off;
524
        newpos = file->pos;
525
        futex_up(&file->lock);
526
        ipc_answer_1(rid, EOK, newpos);
527
        return;
528
    }
529
    if (whence == SEEK_END) {
530
        rwlock_read_lock(&file->node->contents_rwlock);
531
        size_t size = file->node->size;
532
        rwlock_read_unlock(&file->node->contents_rwlock);
533
        if (size + off < size) {
534
            futex_up(&file->lock);
535
            ipc_answer_0(rid, EOVERFLOW);
536
            return;
537
        }
538
        newpos = size + off;
539
        futex_up(&file->lock);
540
        ipc_answer_1(rid, EOK, newpos);
541
        return;
542
    }
543
    futex_up(&file->lock);
544
    ipc_answer_0(rid, EINVAL);
545
}
546
 
2770 jermar 547
int
548
vfs_truncate_internal(fs_handle_t fs_handle, dev_handle_t dev_handle,
549
    fs_index_t index, size_t size)
2748 jermar 550
{
551
    ipcarg_t rc;
552
    int fs_phone;
553
 
554
    fs_phone = vfs_grab_phone(fs_handle);
555
    rc = async_req_3_0(fs_phone, VFS_TRUNCATE, (ipcarg_t)dev_handle,
556
        (ipcarg_t)index, (ipcarg_t)size);
557
    vfs_release_phone(fs_phone);
558
    return (int)rc;
559
}
560
 
2693 jermar 561
void vfs_truncate(ipc_callid_t rid, ipc_call_t *request)
562
{
563
    int fd = IPC_GET_ARG1(*request);
564
    size_t size = IPC_GET_ARG2(*request);
2748 jermar 565
    int rc;
2693 jermar 566
 
567
    vfs_file_t *file = vfs_file_get(fd);
568
    if (!file) {
569
        ipc_answer_0(rid, ENOENT);
570
        return;
571
    }
572
    futex_down(&file->lock);
573
 
574
    rwlock_write_lock(&file->node->contents_rwlock);
2748 jermar 575
    rc = vfs_truncate_internal(file->node->fs_handle,
576
        file->node->dev_handle, file->node->index, size);
2693 jermar 577
    if (rc == EOK)
578
        file->node->size = size;
579
    rwlock_write_unlock(&file->node->contents_rwlock);
580
 
581
    futex_up(&file->lock);
2748 jermar 582
    ipc_answer_0(rid, (ipcarg_t)rc);
2693 jermar 583
}
584
 
2707 jermar 585
void vfs_mkdir(ipc_callid_t rid, ipc_call_t *request)
586
{
587
    int mode = IPC_GET_ARG1(*request);
2735 jermar 588
 
2707 jermar 589
    size_t len;
590
    ipc_callid_t callid;
591
 
592
    if (!ipc_data_write_receive(&callid, &len)) {
593
        ipc_answer_0(callid, EINVAL);
594
        ipc_answer_0(rid, EINVAL);
595
        return;
596
    }
2752 jermar 597
    char *path = malloc(len + 1);
2707 jermar 598
    if (!path) {
599
        ipc_answer_0(callid, ENOMEM);
600
        ipc_answer_0(rid, ENOMEM);
601
        return;
602
    }
603
    int rc;
604
    if ((rc = ipc_data_write_finalize(callid, path, len))) {
605
        ipc_answer_0(rid, rc);
606
        free(path);
607
        return;
608
    }
2752 jermar 609
    path[len] = '\0';
2707 jermar 610
 
611
    rwlock_write_lock(&namespace_rwlock);
612
    int lflag = L_DIRECTORY | L_CREATE | L_EXCLUSIVE;
2752 jermar 613
    rc = vfs_lookup_internal(path, lflag, NULL, NULL);
2707 jermar 614
    rwlock_write_unlock(&namespace_rwlock);
615
    free(path);
616
    ipc_answer_0(rid, rc);
617
}
618
 
2735 jermar 619
void vfs_unlink(ipc_callid_t rid, ipc_call_t *request)
620
{
621
    int lflag = IPC_GET_ARG1(*request);
622
 
623
    size_t len;
624
    ipc_callid_t callid;
625
 
626
    if (!ipc_data_write_receive(&callid, &len)) {
627
        ipc_answer_0(callid, EINVAL);
628
        ipc_answer_0(rid, EINVAL);
629
        return;
630
    }
2752 jermar 631
    char *path = malloc(len + 1);
2735 jermar 632
    if (!path) {
633
        ipc_answer_0(callid, ENOMEM);
634
        ipc_answer_0(rid, ENOMEM);
635
        return;
636
    }
637
    int rc;
638
    if ((rc = ipc_data_write_finalize(callid, path, len))) {
639
        ipc_answer_0(rid, rc);
640
        free(path);
641
        return;
642
    }
2752 jermar 643
    path[len] = '\0';
2735 jermar 644
 
645
    rwlock_write_lock(&namespace_rwlock);
646
    lflag &= L_DIRECTORY;   /* sanitize lflag */
647
    vfs_lookup_res_t lr;
2763 jermar 648
    rc = vfs_lookup_internal(path, lflag | L_UNLINK, &lr, NULL);
2735 jermar 649
    free(path);
650
    if (rc != EOK) {
651
        rwlock_write_unlock(&namespace_rwlock);
652
        ipc_answer_0(rid, rc);
653
        return;
654
    }
655
 
656
    /*
657
     * The name has already been unlinked by vfs_lookup_internal().
658
     * We have to get and put the VFS node to ensure that it is
2742 jermar 659
     * VFS_DESTROY'ed after the last reference to it is dropped.
2735 jermar 660
     */
661
    vfs_node_t *node = vfs_node_get(&lr);
2766 jermar 662
    futex_down(&nodes_futex);
2735 jermar 663
    node->lnkcnt--;
2766 jermar 664
    futex_up(&nodes_futex);
2735 jermar 665
    rwlock_write_unlock(&namespace_rwlock);
666
    vfs_node_put(node);
667
    ipc_answer_0(rid, EOK);
668
}
669
 
2763 jermar 670
void vfs_rename(ipc_callid_t rid, ipc_call_t *request)
671
{
672
    size_t len;
673
    ipc_callid_t callid;
674
    int rc;
675
 
676
    /* Retrieve the old path. */
677
    if (!ipc_data_write_receive(&callid, &len)) {
678
        ipc_answer_0(callid, EINVAL);
679
        ipc_answer_0(rid, EINVAL);
680
        return;
681
    }
682
    char *old = malloc(len + 1);
683
    if (!old) {
684
        ipc_answer_0(callid, ENOMEM);
685
        ipc_answer_0(rid, ENOMEM);
686
        return;
687
    }
688
    if ((rc = ipc_data_write_finalize(callid, old, len))) {
689
        ipc_answer_0(rid, rc);
690
        free(old);
691
        return;
692
    }
693
    old[len] = '\0';
694
 
695
    /* Retrieve the new path. */
696
    if (!ipc_data_write_receive(&callid, &len)) {
697
        ipc_answer_0(callid, EINVAL);
698
        ipc_answer_0(rid, EINVAL);
699
        free(old);
700
        return;
701
    }
702
    char *new = malloc(len + 1);
703
    if (!new) {
704
        ipc_answer_0(callid, ENOMEM);
705
        ipc_answer_0(rid, ENOMEM);
706
        free(old);
707
        return;
708
    }
709
    if ((rc = ipc_data_write_finalize(callid, new, len))) {
710
        ipc_answer_0(rid, rc);
711
        free(old);
712
        free(new);
713
        return;
714
    }
715
    new[len] = '\0';
716
 
717
    char *oldc = canonify(old, &len);
718
    char *newc = canonify(new, NULL);
719
    if (!oldc || !newc) {
720
        ipc_answer_0(rid, EINVAL);
721
        free(old);
722
        free(new);
723
        return;
724
    }
725
    if (!strncmp(newc, oldc, len)) {
726
        /* oldc is a prefix of newc */
727
        ipc_answer_0(rid, EINVAL);
728
        free(old);
729
        free(new);
730
        return;
731
    }
732
 
733
    vfs_lookup_res_t old_lr;
734
    vfs_lookup_res_t new_lr;
735
    vfs_lookup_res_t new_par_lr;
736
    rwlock_write_lock(&namespace_rwlock);
737
    /* Lookup the node belonging to the old file name. */
738
    rc = vfs_lookup_internal(oldc, L_NONE, &old_lr, NULL);
739
    if (rc != EOK) {
740
        rwlock_write_unlock(&namespace_rwlock);
741
        ipc_answer_0(rid, rc);
742
        free(old);
743
        free(new);
744
        return;
745
    }
746
    vfs_node_t *old_node = vfs_node_get(&old_lr);
747
    if (!old_node) {
748
        rwlock_write_unlock(&namespace_rwlock);
749
        ipc_answer_0(rid, ENOMEM);
750
        free(old);
751
        free(new);
752
        return;
753
    }
754
    /* Lookup parent of the new file name. */
755
    rc = vfs_lookup_internal(newc, L_PARENT, &new_par_lr, NULL);
756
    if (rc != EOK) {
757
        rwlock_write_unlock(&namespace_rwlock);
758
        ipc_answer_0(rid, rc);
759
        free(old);
760
        free(new);
761
        return;
762
    }
763
    /* Check whether linking to the same file system instance. */
764
    if ((old_node->fs_handle != new_par_lr.triplet.fs_handle) ||
765
        (old_node->dev_handle != new_par_lr.triplet.dev_handle)) {
766
        rwlock_write_unlock(&namespace_rwlock);
767
        ipc_answer_0(rid, EXDEV);   /* different file systems */
768
        free(old);
769
        free(new);
770
        return;
771
    }
772
    /* Destroy the old link for the new name. */
773
    vfs_node_t *new_node = NULL;
774
    rc = vfs_lookup_internal(newc, L_UNLINK, &new_lr, NULL);
775
    switch (rc) {
776
    case ENOENT:
777
        /* simply not in our way */
778
        break;
779
    case EOK:
780
        new_node = vfs_node_get(&new_lr);
781
        if (!new_node) {
782
            rwlock_write_unlock(&namespace_rwlock);
783
            ipc_answer_0(rid, ENOMEM);
784
            free(old);
785
            free(new);
786
            return;
787
        }
2766 jermar 788
        futex_down(&nodes_futex);
2763 jermar 789
        new_node->lnkcnt--;
2766 jermar 790
        futex_up(&nodes_futex);
2763 jermar 791
        break;
792
    default:
793
        rwlock_write_unlock(&namespace_rwlock);
794
        ipc_answer_0(rid, ENOTEMPTY);
795
        free(old);
796
        free(new);
797
        return;
798
    }
799
    /* Create the new link for the new name. */
800
    rc = vfs_lookup_internal(newc, L_LINK, NULL, NULL, old_node->index);
801
    if (rc != EOK) {
802
        rwlock_write_unlock(&namespace_rwlock);
803
        if (new_node)
804
            vfs_node_put(new_node);
805
        ipc_answer_0(rid, rc);
806
        free(old);
807
        free(new);
808
        return;
809
    }
2766 jermar 810
    futex_down(&nodes_futex);
2763 jermar 811
    old_node->lnkcnt++;
2766 jermar 812
    futex_up(&nodes_futex);
2763 jermar 813
    /* Destroy the link for the old name. */
814
    rc = vfs_lookup_internal(oldc, L_UNLINK, NULL, NULL);
815
    if (rc != EOK) {
816
        rwlock_write_unlock(&namespace_rwlock);
817
        vfs_node_put(old_node);
818
        if (new_node)
819
            vfs_node_put(new_node);
820
        ipc_answer_0(rid, rc);
821
        free(old);
822
        free(new);
823
        return;
824
    }
2766 jermar 825
    futex_down(&nodes_futex);
2763 jermar 826
    old_node->lnkcnt--;
2766 jermar 827
    futex_up(&nodes_futex);
2763 jermar 828
    rwlock_write_unlock(&namespace_rwlock);
829
    vfs_node_put(old_node);
830
    if (new_node)
831
        vfs_node_put(new_node);
832
    free(old);
833
    free(new);
834
    ipc_answer_0(rid, EOK);
835
}
836
 
2689 jermar 837
/**
838
 * @}
839
 */