source: mainline/uspace/srv/vfs/vfs_ops.c@ 319f4fb

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 319f4fb was 4b995b92, checked in by Jakub Jermar <jakub@…>, 15 years ago

Introduce the L_NOCROSS_LAST_MP lookup flag and treat the last mount point node
according to it in libfs_lookup().
  • Property mode set to 100644
File size: 33.5 KB
Line 
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
38#include "vfs.h"
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 <fibril_synch.h>
47#include <adt/list.h>
48#include <unistd.h>
49#include <ctype.h>
50#include <fcntl.h>
51#include <assert.h>
52#include <vfs/canonify.h>
53
54/* Forward declarations of static functions. */
55static int vfs_truncate_internal(fs_handle_t, dev_handle_t, fs_index_t, size_t);
56
57/**
58 * This rwlock prevents the race between a triplet-to-VFS-node resolution and a
59 * concurrent VFS operation which modifies the file system namespace.
60 */
61FIBRIL_RWLOCK_INITIALIZE(namespace_rwlock);
62
63vfs_pair_t rootfs = {
64 .fs_handle = 0,
65 .dev_handle = 0
66};
67
68static void vfs_mount_internal(ipc_callid_t rid, dev_handle_t dev_handle,
69 fs_handle_t fs_handle, char *mp, char *opts)
70{
71 vfs_lookup_res_t mp_res;
72 vfs_lookup_res_t mr_res;
73 vfs_node_t *mp_node = NULL;
74 vfs_node_t *mr_node;
75 fs_index_t rindex;
76 size_t rsize;
77 unsigned rlnkcnt;
78 ipcarg_t rc;
79 int phone;
80 aid_t msg;
81 ipc_call_t answer;
82
83 /* Resolve the path to the mountpoint. */
84 fibril_rwlock_write_lock(&namespace_rwlock);
85 if (rootfs.fs_handle) {
86 /* We already have the root FS. */
87 if (str_cmp(mp, "/") == 0) {
88 /* Trying to mount root FS over root FS */
89 fibril_rwlock_write_unlock(&namespace_rwlock);
90 ipc_answer_0(rid, EBUSY);
91 return;
92 }
93
94 rc = vfs_lookup_internal(mp, L_DIRECTORY, &mp_res, NULL);
95 if (rc != EOK) {
96 /* The lookup failed for some reason. */
97 fibril_rwlock_write_unlock(&namespace_rwlock);
98 ipc_answer_0(rid, rc);
99 return;
100 }
101
102 mp_node = vfs_node_get(&mp_res);
103 if (!mp_node) {
104 fibril_rwlock_write_unlock(&namespace_rwlock);
105 ipc_answer_0(rid, ENOMEM);
106 return;
107 }
108
109 /*
110 * Now we hold a reference to mp_node.
111 * It will be dropped upon the corresponding VFS_IN_UNMOUNT.
112 * This prevents the mount point from being deleted.
113 */
114 } else {
115 /* We still don't have the root file system mounted. */
116 if (str_cmp(mp, "/") == 0) {
117 /*
118 * For this simple, but important case,
119 * we are almost done.
120 */
121
122 /* Tell the mountee that it is being mounted. */
123 phone = vfs_grab_phone(fs_handle);
124 msg = async_send_1(phone, VFS_OUT_MOUNTED,
125 (ipcarg_t) dev_handle, &answer);
126 /* send the mount options */
127 rc = async_data_write_start(phone, (void *)opts,
128 str_size(opts));
129 if (rc != EOK) {
130 async_wait_for(msg, NULL);
131 vfs_release_phone(phone);
132 fibril_rwlock_write_unlock(&namespace_rwlock);
133 ipc_answer_0(rid, rc);
134 return;
135 }
136 async_wait_for(msg, &rc);
137 vfs_release_phone(phone);
138
139 if (rc != EOK) {
140 fibril_rwlock_write_unlock(&namespace_rwlock);
141 ipc_answer_0(rid, rc);
142 return;
143 }
144
145 rindex = (fs_index_t) IPC_GET_ARG1(answer);
146 rsize = (size_t) IPC_GET_ARG2(answer);
147 rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
148
149 mr_res.triplet.fs_handle = fs_handle;
150 mr_res.triplet.dev_handle = dev_handle;
151 mr_res.triplet.index = rindex;
152 mr_res.size = rsize;
153 mr_res.lnkcnt = rlnkcnt;
154 mr_res.type = VFS_NODE_DIRECTORY;
155
156 rootfs.fs_handle = fs_handle;
157 rootfs.dev_handle = dev_handle;
158
159 /* Add reference to the mounted root. */
160 mr_node = vfs_node_get(&mr_res);
161 assert(mr_node);
162
163 fibril_rwlock_write_unlock(&namespace_rwlock);
164 ipc_answer_0(rid, rc);
165 return;
166 } else {
167 /*
168 * We can't resolve this without the root filesystem
169 * being mounted first.
170 */
171 fibril_rwlock_write_unlock(&namespace_rwlock);
172 ipc_answer_0(rid, ENOENT);
173 return;
174 }
175 }
176
177 /*
178 * At this point, we have all necessary pieces: file system and device
179 * handles, and we know the mount point VFS node.
180 */
181
182 int mountee_phone = vfs_grab_phone(fs_handle);
183 assert(mountee_phone >= 0);
184
185 phone = vfs_grab_phone(mp_res.triplet.fs_handle);
186 msg = async_send_4(phone, VFS_OUT_MOUNT,
187 (ipcarg_t) mp_res.triplet.dev_handle,
188 (ipcarg_t) mp_res.triplet.index,
189 (ipcarg_t) fs_handle,
190 (ipcarg_t) dev_handle, &answer);
191
192 /* send connection */
193 rc = async_req_1_0(phone, IPC_M_CONNECTION_CLONE, mountee_phone);
194 if (rc != EOK) {
195 async_wait_for(msg, NULL);
196 vfs_release_phone(mountee_phone);
197 vfs_release_phone(phone);
198 /* Mount failed, drop reference to mp_node. */
199 if (mp_node)
200 vfs_node_put(mp_node);
201 ipc_answer_0(rid, rc);
202 fibril_rwlock_write_unlock(&namespace_rwlock);
203 return;
204 }
205
206 vfs_release_phone(mountee_phone);
207
208 /* send the mount options */
209 rc = async_data_write_start(phone, (void *)opts, str_size(opts));
210 if (rc != EOK) {
211 async_wait_for(msg, NULL);
212 vfs_release_phone(phone);
213 /* Mount failed, drop reference to mp_node. */
214 if (mp_node)
215 vfs_node_put(mp_node);
216 fibril_rwlock_write_unlock(&namespace_rwlock);
217 ipc_answer_0(rid, rc);
218 return;
219 }
220 async_wait_for(msg, &rc);
221 vfs_release_phone(phone);
222
223 if (rc == EOK) {
224 rindex = (fs_index_t) IPC_GET_ARG1(answer);
225 rsize = (size_t) IPC_GET_ARG2(answer);
226 rlnkcnt = (unsigned) IPC_GET_ARG3(answer);
227
228 mr_res.triplet.fs_handle = fs_handle;
229 mr_res.triplet.dev_handle = dev_handle;
230 mr_res.triplet.index = rindex;
231 mr_res.size = rsize;
232 mr_res.lnkcnt = rlnkcnt;
233 mr_res.type = VFS_NODE_DIRECTORY;
234
235 /* Add reference to the mounted root. */
236 mr_node = vfs_node_get(&mr_res);
237 assert(mr_node);
238 } else {
239 /* Mount failed, drop reference to mp_node. */
240 if (mp_node)
241 vfs_node_put(mp_node);
242 }
243
244 ipc_answer_0(rid, rc);
245 fibril_rwlock_write_unlock(&namespace_rwlock);
246}
247
248void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
249{
250 /*
251 * We expect the library to do the device-name to device-handle
252 * translation for us, thus the device handle will arrive as ARG1
253 * in the request.
254 */
255 dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
256
257 /*
258 * Mount flags are passed as ARG2.
259 */
260 unsigned int flags = (unsigned int) IPC_GET_ARG2(*request);
261
262 /*
263 * For now, don't make use of ARG3, but it can be used to
264 * carry mount options in the future.
265 */
266
267 /* We want the client to send us the mount point. */
268 ipc_callid_t callid;
269 size_t size;
270 if (!async_data_write_receive(&callid, &size)) {
271 ipc_answer_0(callid, EINVAL);
272 ipc_answer_0(rid, EINVAL);
273 return;
274 }
275
276 /* Check whether size is reasonable wrt. the mount point. */
277 if ((size < 1) || (size > MAX_PATH_LEN)) {
278 ipc_answer_0(callid, EINVAL);
279 ipc_answer_0(rid, EINVAL);
280 return;
281 }
282
283 /* Allocate buffer for the mount point data being received. */
284 char *mp = malloc(size + 1);
285 if (!mp) {
286 ipc_answer_0(callid, ENOMEM);
287 ipc_answer_0(rid, ENOMEM);
288 return;
289 }
290
291 /* Deliver the mount point. */
292 ipcarg_t retval = async_data_write_finalize(callid, mp, size);
293 if (retval != EOK) {
294 ipc_answer_0(rid, retval);
295 free(mp);
296 return;
297 }
298 mp[size] = '\0';
299
300 /* Now we expect to receive the mount options. */
301 if (!async_data_write_receive(&callid, &size)) {
302 ipc_answer_0(callid, EINVAL);
303 ipc_answer_0(rid, EINVAL);
304 free(mp);
305 return;
306 }
307
308 /* Check the offered options size. */
309 if (size > MAX_MNTOPTS_LEN) {
310 ipc_answer_0(callid, EINVAL);
311 ipc_answer_0(rid, EINVAL);
312 free(mp);
313 return;
314 }
315
316 /* Allocate buffer for the mount options. */
317 char *opts = (char *) malloc(size + 1);
318 if (!opts) {
319 ipc_answer_0(callid, ENOMEM);
320 ipc_answer_0(rid, ENOMEM);
321 free(mp);
322 return;
323 }
324
325 /* Deliver the mount options. */
326 retval = async_data_write_finalize(callid, opts, size);
327 if (retval != EOK) {
328 ipc_answer_0(rid, retval);
329 free(mp);
330 free(opts);
331 return;
332 }
333 opts[size] = '\0';
334
335 /*
336 * Now, we expect the client to send us data with the name of the file
337 * system.
338 */
339 if (!async_data_write_receive(&callid, &size)) {
340 ipc_answer_0(callid, EINVAL);
341 ipc_answer_0(rid, EINVAL);
342 free(mp);
343 free(opts);
344 return;
345 }
346
347 /*
348 * Don't receive more than is necessary for storing a full file system
349 * name.
350 */
351 if ((size < 1) || (size > FS_NAME_MAXLEN)) {
352 ipc_answer_0(callid, EINVAL);
353 ipc_answer_0(rid, EINVAL);
354 free(mp);
355 free(opts);
356 return;
357 }
358
359 /*
360 * Allocate buffer for file system name.
361 */
362 char *fs_name = (char *) malloc(size + 1);
363 if (fs_name == NULL) {
364 ipc_answer_0(callid, ENOMEM);
365 ipc_answer_0(rid, ENOMEM);
366 free(mp);
367 free(opts);
368 return;
369 }
370
371 /* Deliver the file system name. */
372 retval = async_data_write_finalize(callid, fs_name, size);
373 if (retval != EOK) {
374 ipc_answer_0(rid, retval);
375 free(mp);
376 free(opts);
377 free(fs_name);
378 return;
379 }
380 fs_name[size] = '\0';
381
382 /*
383 * Wait for IPC_M_PING so that we can return an error if we don't know
384 * fs_name.
385 */
386 ipc_call_t data;
387 callid = async_get_call(&data);
388 if (IPC_GET_METHOD(data) != IPC_M_PING) {
389 ipc_answer_0(callid, ENOTSUP);
390 ipc_answer_0(rid, ENOTSUP);
391 free(mp);
392 free(opts);
393 free(fs_name);
394 return;
395 }
396
397 /*
398 * Check if we know a file system with the same name as is in fs_name.
399 * This will also give us its file system handle.
400 */
401 fibril_mutex_lock(&fs_head_lock);
402 fs_handle_t fs_handle;
403recheck:
404 fs_handle = fs_name_to_handle(fs_name, false);
405 if (!fs_handle) {
406 if (flags & IPC_FLAG_BLOCKING) {
407 fibril_condvar_wait(&fs_head_cv, &fs_head_lock);
408 goto recheck;
409 }
410
411 fibril_mutex_unlock(&fs_head_lock);
412 ipc_answer_0(callid, ENOENT);
413 ipc_answer_0(rid, ENOENT);
414 free(mp);
415 free(fs_name);
416 free(opts);
417 return;
418 }
419 fibril_mutex_unlock(&fs_head_lock);
420
421 /* Acknowledge that we know fs_name. */
422 ipc_answer_0(callid, EOK);
423
424 /* Do the mount */
425 vfs_mount_internal(rid, dev_handle, fs_handle, mp, opts);
426 free(mp);
427 free(fs_name);
428 free(opts);
429}
430
431void vfs_unmount(ipc_callid_t rid, ipc_call_t *request)
432{
433 ipc_answer_0(rid, ENOTSUP);
434}
435
436void vfs_open(ipc_callid_t rid, ipc_call_t *request)
437{
438 if (!vfs_files_init()) {
439 ipc_answer_0(rid, ENOMEM);
440 return;
441 }
442
443 /*
444 * The POSIX interface is open(path, oflag, mode).
445 * We can receive oflags and mode along with the VFS_IN_OPEN call;
446 * the path will need to arrive in another call.
447 *
448 * We also receive one private, non-POSIX set of flags called lflag
449 * used to pass information to vfs_lookup_internal().
450 */
451 int lflag = IPC_GET_ARG1(*request);
452 int oflag = IPC_GET_ARG2(*request);
453 int mode = IPC_GET_ARG3(*request);
454 size_t len;
455
456 /* Ignore mode for now. */
457 (void) mode;
458
459 /*
460 * Make sure that we are called with exactly one of L_FILE and
461 * L_DIRECTORY. Make sure that the user does not pass L_OPEN or
462 * L_NOCROSS_LAST_MP.
463 */
464 if (((lflag & (L_FILE | L_DIRECTORY)) == 0) ||
465 ((lflag & (L_FILE | L_DIRECTORY)) == (L_FILE | L_DIRECTORY)) ||
466 (lflag & L_OPEN) || (lflag & L_NOCROSS_LAST_MP)) {
467 ipc_answer_0(rid, EINVAL);
468 return;
469 }
470
471 if (oflag & O_CREAT)
472 lflag |= L_CREATE;
473 if (oflag & O_EXCL)
474 lflag |= L_EXCLUSIVE;
475
476 ipc_callid_t callid;
477 if (!async_data_write_receive(&callid, &len)) {
478 ipc_answer_0(callid, EINVAL);
479 ipc_answer_0(rid, EINVAL);
480 return;
481 }
482
483 char *path = malloc(len + 1);
484 if (!path) {
485 ipc_answer_0(callid, ENOMEM);
486 ipc_answer_0(rid, ENOMEM);
487 return;
488 }
489
490 int rc;
491 if ((rc = async_data_write_finalize(callid, path, len))) {
492 ipc_answer_0(rid, rc);
493 free(path);
494 return;
495 }
496 path[len] = '\0';
497
498 /*
499 * Avoid the race condition in which the file can be deleted before we
500 * find/create-and-lock the VFS node corresponding to the looked-up
501 * triplet.
502 */
503 if (lflag & L_CREATE)
504 fibril_rwlock_write_lock(&namespace_rwlock);
505 else
506 fibril_rwlock_read_lock(&namespace_rwlock);
507
508 /* The path is now populated and we can call vfs_lookup_internal(). */
509 vfs_lookup_res_t lr;
510 rc = vfs_lookup_internal(path, lflag | L_OPEN, &lr, NULL);
511 if (rc != EOK) {
512 if (lflag & L_CREATE)
513 fibril_rwlock_write_unlock(&namespace_rwlock);
514 else
515 fibril_rwlock_read_unlock(&namespace_rwlock);
516 ipc_answer_0(rid, rc);
517 free(path);
518 return;
519 }
520
521 /* Path is no longer needed. */
522 free(path);
523
524 vfs_node_t *node = vfs_node_get(&lr);
525 if (lflag & L_CREATE)
526 fibril_rwlock_write_unlock(&namespace_rwlock);
527 else
528 fibril_rwlock_read_unlock(&namespace_rwlock);
529
530 /* Truncate the file if requested and if necessary. */
531 if (oflag & O_TRUNC) {
532 fibril_rwlock_write_lock(&node->contents_rwlock);
533 if (node->size) {
534 rc = vfs_truncate_internal(node->fs_handle,
535 node->dev_handle, node->index, 0);
536 if (rc) {
537 fibril_rwlock_write_unlock(&node->contents_rwlock);
538 vfs_node_put(node);
539 ipc_answer_0(rid, rc);
540 return;
541 }
542 node->size = 0;
543 }
544 fibril_rwlock_write_unlock(&node->contents_rwlock);
545 }
546
547 /*
548 * Get ourselves a file descriptor and the corresponding vfs_file_t
549 * structure.
550 */
551 int fd = vfs_fd_alloc((oflag & O_DESC) != 0);
552 if (fd < 0) {
553 vfs_node_put(node);
554 ipc_answer_0(rid, fd);
555 return;
556 }
557 vfs_file_t *file = vfs_file_get(fd);
558 file->node = node;
559 if (oflag & O_APPEND)
560 file->append = true;
561
562 /*
563 * The following increase in reference count is for the fact that the
564 * file is being opened and that a file structure is pointing to it.
565 * It is necessary so that the file will not disappear when
566 * vfs_node_put() is called. The reference will be dropped by the
567 * respective VFS_IN_CLOSE.
568 */
569 vfs_node_addref(node);
570 vfs_node_put(node);
571
572 /* Success! Return the new file descriptor to the client. */
573 ipc_answer_1(rid, EOK, fd);
574}
575
576void vfs_open_node(ipc_callid_t rid, ipc_call_t *request)
577{
578 // FIXME: check for sanity of the supplied fs, dev and index
579
580 if (!vfs_files_init()) {
581 ipc_answer_0(rid, ENOMEM);
582 return;
583 }
584
585 /*
586 * The interface is open_node(fs, dev, index, oflag).
587 */
588 vfs_lookup_res_t lr;
589
590 lr.triplet.fs_handle = IPC_GET_ARG1(*request);
591 lr.triplet.dev_handle = IPC_GET_ARG2(*request);
592 lr.triplet.index = IPC_GET_ARG3(*request);
593 int oflag = IPC_GET_ARG4(*request);
594
595 fibril_rwlock_read_lock(&namespace_rwlock);
596
597 int rc = vfs_open_node_internal(&lr);
598 if (rc != EOK) {
599 fibril_rwlock_read_unlock(&namespace_rwlock);
600 ipc_answer_0(rid, rc);
601 return;
602 }
603
604 vfs_node_t *node = vfs_node_get(&lr);
605 fibril_rwlock_read_unlock(&namespace_rwlock);
606
607 /* Truncate the file if requested and if necessary. */
608 if (oflag & O_TRUNC) {
609 fibril_rwlock_write_lock(&node->contents_rwlock);
610 if (node->size) {
611 rc = vfs_truncate_internal(node->fs_handle,
612 node->dev_handle, node->index, 0);
613 if (rc) {
614 fibril_rwlock_write_unlock(&node->contents_rwlock);
615 vfs_node_put(node);
616 ipc_answer_0(rid, rc);
617 return;
618 }
619 node->size = 0;
620 }
621 fibril_rwlock_write_unlock(&node->contents_rwlock);
622 }
623
624 /*
625 * Get ourselves a file descriptor and the corresponding vfs_file_t
626 * structure.
627 */
628 int fd = vfs_fd_alloc((oflag & O_DESC) != 0);
629 if (fd < 0) {
630 vfs_node_put(node);
631 ipc_answer_0(rid, fd);
632 return;
633 }
634 vfs_file_t *file = vfs_file_get(fd);
635 file->node = node;
636 if (oflag & O_APPEND)
637 file->append = true;
638
639 /*
640 * The following increase in reference count is for the fact that the
641 * file is being opened and that a file structure is pointing to it.
642 * It is necessary so that the file will not disappear when
643 * vfs_node_put() is called. The reference will be dropped by the
644 * respective VFS_IN_CLOSE.
645 */
646 vfs_node_addref(node);
647 vfs_node_put(node);
648
649 /* Success! Return the new file descriptor to the client. */
650 ipc_answer_1(rid, EOK, fd);
651}
652
653void vfs_sync(ipc_callid_t rid, ipc_call_t *request)
654{
655 int fd = IPC_GET_ARG1(*request);
656
657 /* Lookup the file structure corresponding to the file descriptor. */
658 vfs_file_t *file = vfs_file_get(fd);
659 if (!file) {
660 ipc_answer_0(rid, ENOENT);
661 return;
662 }
663
664 /*
665 * Lock the open file structure so that no other thread can manipulate
666 * the same open file at a time.
667 */
668 fibril_mutex_lock(&file->lock);
669 int fs_phone = vfs_grab_phone(file->node->fs_handle);
670
671 /* Make a VFS_OUT_SYMC request at the destination FS server. */
672 aid_t msg;
673 ipc_call_t answer;
674 msg = async_send_2(fs_phone, VFS_OUT_SYNC, file->node->dev_handle,
675 file->node->index, &answer);
676
677 /* Wait for reply from the FS server. */
678 ipcarg_t rc;
679 async_wait_for(msg, &rc);
680
681 vfs_release_phone(fs_phone);
682 fibril_mutex_unlock(&file->lock);
683
684 ipc_answer_0(rid, rc);
685}
686
687static int vfs_close_internal(vfs_file_t *file)
688{
689 /*
690 * Lock the open file structure so that no other thread can manipulate
691 * the same open file at a time.
692 */
693 fibril_mutex_lock(&file->lock);
694
695 if (file->refcnt <= 1) {
696 /* Only close the file on the destination FS server
697 if there are no more file descriptors (except the
698 present one) pointing to this file. */
699
700 int fs_phone = vfs_grab_phone(file->node->fs_handle);
701
702 /* Make a VFS_OUT_CLOSE request at the destination FS server. */
703 aid_t msg;
704 ipc_call_t answer;
705 msg = async_send_2(fs_phone, VFS_OUT_CLOSE, file->node->dev_handle,
706 file->node->index, &answer);
707
708 /* Wait for reply from the FS server. */
709 ipcarg_t rc;
710 async_wait_for(msg, &rc);
711
712 vfs_release_phone(fs_phone);
713 fibril_mutex_unlock(&file->lock);
714
715 return IPC_GET_ARG1(answer);
716 }
717
718 fibril_mutex_unlock(&file->lock);
719 return EOK;
720}
721
722void vfs_close(ipc_callid_t rid, ipc_call_t *request)
723{
724 int fd = IPC_GET_ARG1(*request);
725
726 /* Lookup the file structure corresponding to the file descriptor. */
727 vfs_file_t *file = vfs_file_get(fd);
728 if (!file) {
729 ipc_answer_0(rid, ENOENT);
730 return;
731 }
732
733 int ret = vfs_close_internal(file);
734 if (ret != EOK)
735 ipc_answer_0(rid, ret);
736
737 ret = vfs_fd_free(fd);
738 ipc_answer_0(rid, ret);
739}
740
741static void vfs_rdwr(ipc_callid_t rid, ipc_call_t *request, bool read)
742{
743
744 /*
745 * The following code strongly depends on the fact that the files data
746 * structure can be only accessed by a single fibril and all file
747 * operations are serialized (i.e. the reads and writes cannot
748 * interleave and a file cannot be closed while it is being read).
749 *
750 * Additional synchronization needs to be added once the table of
751 * open files supports parallel access!
752 */
753
754 int fd = IPC_GET_ARG1(*request);
755
756 /* Lookup the file structure corresponding to the file descriptor. */
757 vfs_file_t *file = vfs_file_get(fd);
758 if (!file) {
759 ipc_answer_0(rid, ENOENT);
760 return;
761 }
762
763 /*
764 * Now we need to receive a call with client's
765 * IPC_M_DATA_READ/IPC_M_DATA_WRITE request.
766 */
767 ipc_callid_t callid;
768 int res;
769 if (read)
770 res = async_data_read_receive(&callid, NULL);
771 else
772 res = async_data_write_receive(&callid, NULL);
773 if (!res) {
774 ipc_answer_0(callid, EINVAL);
775 ipc_answer_0(rid, EINVAL);
776 return;
777 }
778
779 /*
780 * Lock the open file structure so that no other thread can manipulate
781 * the same open file at a time.
782 */
783 fibril_mutex_lock(&file->lock);
784
785 /*
786 * Lock the file's node so that no other client can read/write to it at
787 * the same time.
788 */
789 if (read)
790 fibril_rwlock_read_lock(&file->node->contents_rwlock);
791 else
792 fibril_rwlock_write_lock(&file->node->contents_rwlock);
793
794 if (file->node->type == VFS_NODE_DIRECTORY) {
795 /*
796 * Make sure that no one is modifying the namespace
797 * while we are in readdir().
798 */
799 assert(read);
800 fibril_rwlock_read_lock(&namespace_rwlock);
801 }
802
803 int fs_phone = vfs_grab_phone(file->node->fs_handle);
804
805 /* Make a VFS_READ/VFS_WRITE request at the destination FS server. */
806 aid_t msg;
807 ipc_call_t answer;
808 if (!read && file->append)
809 file->pos = file->node->size;
810 msg = async_send_3(fs_phone, read ? VFS_OUT_READ : VFS_OUT_WRITE,
811 file->node->dev_handle, file->node->index, file->pos, &answer);
812
813 /*
814 * Forward the IPC_M_DATA_READ/IPC_M_DATA_WRITE request to the
815 * destination FS server. The call will be routed as if sent by
816 * ourselves. Note that call arguments are immutable in this case so we
817 * don't have to bother.
818 */
819 ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
820
821 /* Wait for reply from the FS server. */
822 ipcarg_t rc;
823 async_wait_for(msg, &rc);
824
825 vfs_release_phone(fs_phone);
826
827 size_t bytes = IPC_GET_ARG1(answer);
828
829 if (file->node->type == VFS_NODE_DIRECTORY)
830 fibril_rwlock_read_unlock(&namespace_rwlock);
831
832 /* Unlock the VFS node. */
833 if (read)
834 fibril_rwlock_read_unlock(&file->node->contents_rwlock);
835 else {
836 /* Update the cached version of node's size. */
837 if (rc == EOK)
838 file->node->size = IPC_GET_ARG2(answer);
839 fibril_rwlock_write_unlock(&file->node->contents_rwlock);
840 }
841
842 /* Update the position pointer and unlock the open file. */
843 if (rc == EOK)
844 file->pos += bytes;
845 fibril_mutex_unlock(&file->lock);
846
847 /*
848 * FS server's reply is the final result of the whole operation we
849 * return to the client.
850 */
851 ipc_answer_1(rid, rc, bytes);
852}
853
854void vfs_read(ipc_callid_t rid, ipc_call_t *request)
855{
856 vfs_rdwr(rid, request, true);
857}
858
859void vfs_write(ipc_callid_t rid, ipc_call_t *request)
860{
861 vfs_rdwr(rid, request, false);
862}
863
864void vfs_seek(ipc_callid_t rid, ipc_call_t *request)
865{
866 int fd = (int) IPC_GET_ARG1(*request);
867 off_t off = (off_t) IPC_GET_ARG2(*request);
868 int whence = (int) IPC_GET_ARG3(*request);
869
870
871 /* Lookup the file structure corresponding to the file descriptor. */
872 vfs_file_t *file = vfs_file_get(fd);
873 if (!file) {
874 ipc_answer_0(rid, ENOENT);
875 return;
876 }
877
878 off_t newpos;
879 fibril_mutex_lock(&file->lock);
880 if (whence == SEEK_SET) {
881 file->pos = off;
882 fibril_mutex_unlock(&file->lock);
883 ipc_answer_1(rid, EOK, off);
884 return;
885 }
886 if (whence == SEEK_CUR) {
887 if (file->pos + off < file->pos) {
888 fibril_mutex_unlock(&file->lock);
889 ipc_answer_0(rid, EOVERFLOW);
890 return;
891 }
892 file->pos += off;
893 newpos = file->pos;
894 fibril_mutex_unlock(&file->lock);
895 ipc_answer_1(rid, EOK, newpos);
896 return;
897 }
898 if (whence == SEEK_END) {
899 fibril_rwlock_read_lock(&file->node->contents_rwlock);
900 size_t size = file->node->size;
901 fibril_rwlock_read_unlock(&file->node->contents_rwlock);
902 if (size + off < size) {
903 fibril_mutex_unlock(&file->lock);
904 ipc_answer_0(rid, EOVERFLOW);
905 return;
906 }
907 newpos = size + off;
908 file->pos = newpos;
909 fibril_mutex_unlock(&file->lock);
910 ipc_answer_1(rid, EOK, newpos);
911 return;
912 }
913 fibril_mutex_unlock(&file->lock);
914 ipc_answer_0(rid, EINVAL);
915}
916
917int
918vfs_truncate_internal(fs_handle_t fs_handle, dev_handle_t dev_handle,
919 fs_index_t index, size_t size)
920{
921 ipcarg_t rc;
922 int fs_phone;
923
924 fs_phone = vfs_grab_phone(fs_handle);
925 rc = async_req_3_0(fs_phone, VFS_OUT_TRUNCATE, (ipcarg_t)dev_handle,
926 (ipcarg_t)index, (ipcarg_t)size);
927 vfs_release_phone(fs_phone);
928 return (int)rc;
929}
930
931void vfs_truncate(ipc_callid_t rid, ipc_call_t *request)
932{
933 int fd = IPC_GET_ARG1(*request);
934 size_t size = IPC_GET_ARG2(*request);
935 int rc;
936
937 vfs_file_t *file = vfs_file_get(fd);
938 if (!file) {
939 ipc_answer_0(rid, ENOENT);
940 return;
941 }
942 fibril_mutex_lock(&file->lock);
943
944 fibril_rwlock_write_lock(&file->node->contents_rwlock);
945 rc = vfs_truncate_internal(file->node->fs_handle,
946 file->node->dev_handle, file->node->index, size);
947 if (rc == EOK)
948 file->node->size = size;
949 fibril_rwlock_write_unlock(&file->node->contents_rwlock);
950
951 fibril_mutex_unlock(&file->lock);
952 ipc_answer_0(rid, (ipcarg_t)rc);
953}
954
955void vfs_fstat(ipc_callid_t rid, ipc_call_t *request)
956{
957 int fd = IPC_GET_ARG1(*request);
958 ipcarg_t rc;
959
960 vfs_file_t *file = vfs_file_get(fd);
961 if (!file) {
962 ipc_answer_0(rid, ENOENT);
963 return;
964 }
965
966 ipc_callid_t callid;
967 if (!async_data_read_receive(&callid, NULL)) {
968 ipc_answer_0(callid, EINVAL);
969 ipc_answer_0(rid, EINVAL);
970 return;
971 }
972
973 fibril_mutex_lock(&file->lock);
974
975 int fs_phone = vfs_grab_phone(file->node->fs_handle);
976
977 aid_t msg;
978 msg = async_send_3(fs_phone, VFS_OUT_STAT, file->node->dev_handle,
979 file->node->index, true, NULL);
980 ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
981 async_wait_for(msg, &rc);
982 vfs_release_phone(fs_phone);
983
984 fibril_mutex_unlock(&file->lock);
985 ipc_answer_0(rid, rc);
986}
987
988void vfs_stat(ipc_callid_t rid, ipc_call_t *request)
989{
990 size_t len;
991 ipc_callid_t callid;
992
993 if (!async_data_write_receive(&callid, &len)) {
994 ipc_answer_0(callid, EINVAL);
995 ipc_answer_0(rid, EINVAL);
996 return;
997 }
998 char *path = malloc(len + 1);
999 if (!path) {
1000 ipc_answer_0(callid, ENOMEM);
1001 ipc_answer_0(rid, ENOMEM);
1002 return;
1003 }
1004 int rc;
1005 if ((rc = async_data_write_finalize(callid, path, len))) {
1006 ipc_answer_0(rid, rc);
1007 free(path);
1008 return;
1009 }
1010 path[len] = '\0';
1011
1012 if (!async_data_read_receive(&callid, NULL)) {
1013 free(path);
1014 ipc_answer_0(callid, EINVAL);
1015 ipc_answer_0(rid, EINVAL);
1016 return;
1017 }
1018
1019 vfs_lookup_res_t lr;
1020 fibril_rwlock_read_lock(&namespace_rwlock);
1021 rc = vfs_lookup_internal(path, L_NONE, &lr, NULL);
1022 free(path);
1023 if (rc != EOK) {
1024 fibril_rwlock_read_unlock(&namespace_rwlock);
1025 ipc_answer_0(callid, rc);
1026 ipc_answer_0(rid, rc);
1027 return;
1028 }
1029 vfs_node_t *node = vfs_node_get(&lr);
1030 if (!node) {
1031 fibril_rwlock_read_unlock(&namespace_rwlock);
1032 ipc_answer_0(callid, ENOMEM);
1033 ipc_answer_0(rid, ENOMEM);
1034 return;
1035 }
1036
1037 fibril_rwlock_read_unlock(&namespace_rwlock);
1038
1039 int fs_phone = vfs_grab_phone(node->fs_handle);
1040 aid_t msg;
1041 msg = async_send_3(fs_phone, VFS_OUT_STAT, node->dev_handle,
1042 node->index, false, NULL);
1043 ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
1044
1045 ipcarg_t rv;
1046 async_wait_for(msg, &rv);
1047 vfs_release_phone(fs_phone);
1048
1049 ipc_answer_0(rid, rv);
1050
1051 vfs_node_put(node);
1052}
1053
1054void vfs_mkdir(ipc_callid_t rid, ipc_call_t *request)
1055{
1056 int mode = IPC_GET_ARG1(*request);
1057
1058 size_t len;
1059 ipc_callid_t callid;
1060
1061 if (!async_data_write_receive(&callid, &len)) {
1062 ipc_answer_0(callid, EINVAL);
1063 ipc_answer_0(rid, EINVAL);
1064 return;
1065 }
1066 char *path = malloc(len + 1);
1067 if (!path) {
1068 ipc_answer_0(callid, ENOMEM);
1069 ipc_answer_0(rid, ENOMEM);
1070 return;
1071 }
1072 int rc;
1073 if ((rc = async_data_write_finalize(callid, path, len))) {
1074 ipc_answer_0(rid, rc);
1075 free(path);
1076 return;
1077 }
1078 path[len] = '\0';
1079
1080 /* Ignore mode for now. */
1081 (void) mode;
1082
1083 fibril_rwlock_write_lock(&namespace_rwlock);
1084 int lflag = L_DIRECTORY | L_CREATE | L_EXCLUSIVE;
1085 rc = vfs_lookup_internal(path, lflag, NULL, NULL);
1086 fibril_rwlock_write_unlock(&namespace_rwlock);
1087 free(path);
1088 ipc_answer_0(rid, rc);
1089}
1090
1091void vfs_unlink(ipc_callid_t rid, ipc_call_t *request)
1092{
1093 int lflag = IPC_GET_ARG1(*request);
1094
1095 size_t len;
1096 ipc_callid_t callid;
1097
1098 if (!async_data_write_receive(&callid, &len)) {
1099 ipc_answer_0(callid, EINVAL);
1100 ipc_answer_0(rid, EINVAL);
1101 return;
1102 }
1103 char *path = malloc(len + 1);
1104 if (!path) {
1105 ipc_answer_0(callid, ENOMEM);
1106 ipc_answer_0(rid, ENOMEM);
1107 return;
1108 }
1109 int rc;
1110 if ((rc = async_data_write_finalize(callid, path, len))) {
1111 ipc_answer_0(rid, rc);
1112 free(path);
1113 return;
1114 }
1115 path[len] = '\0';
1116
1117 fibril_rwlock_write_lock(&namespace_rwlock);
1118 lflag &= L_DIRECTORY; /* sanitize lflag */
1119 vfs_lookup_res_t lr;
1120 rc = vfs_lookup_internal(path, lflag | L_UNLINK, &lr, NULL);
1121 free(path);
1122 if (rc != EOK) {
1123 fibril_rwlock_write_unlock(&namespace_rwlock);
1124 ipc_answer_0(rid, rc);
1125 return;
1126 }
1127
1128 /*
1129 * The name has already been unlinked by vfs_lookup_internal().
1130 * We have to get and put the VFS node to ensure that it is
1131 * VFS_OUT_DESTROY'ed after the last reference to it is dropped.
1132 */
1133 vfs_node_t *node = vfs_node_get(&lr);
1134 fibril_mutex_lock(&nodes_mutex);
1135 node->lnkcnt--;
1136 fibril_mutex_unlock(&nodes_mutex);
1137 fibril_rwlock_write_unlock(&namespace_rwlock);
1138 vfs_node_put(node);
1139 ipc_answer_0(rid, EOK);
1140}
1141
1142void vfs_rename(ipc_callid_t rid, ipc_call_t *request)
1143{
1144 size_t olen, nlen;
1145 ipc_callid_t callid;
1146 int rc;
1147
1148 /* Retrieve the old path. */
1149 if (!async_data_write_receive(&callid, &olen)) {
1150 ipc_answer_0(callid, EINVAL);
1151 ipc_answer_0(rid, EINVAL);
1152 return;
1153 }
1154 char *old = malloc(olen + 1);
1155 if (!old) {
1156 ipc_answer_0(callid, ENOMEM);
1157 ipc_answer_0(rid, ENOMEM);
1158 return;
1159 }
1160 if ((rc = async_data_write_finalize(callid, old, olen))) {
1161 ipc_answer_0(rid, rc);
1162 free(old);
1163 return;
1164 }
1165 old[olen] = '\0';
1166
1167 /* Retrieve the new path. */
1168 if (!async_data_write_receive(&callid, &nlen)) {
1169 ipc_answer_0(callid, EINVAL);
1170 ipc_answer_0(rid, EINVAL);
1171 free(old);
1172 return;
1173 }
1174 char *new = malloc(nlen + 1);
1175 if (!new) {
1176 ipc_answer_0(callid, ENOMEM);
1177 ipc_answer_0(rid, ENOMEM);
1178 free(old);
1179 return;
1180 }
1181 if ((rc = async_data_write_finalize(callid, new, nlen))) {
1182 ipc_answer_0(rid, rc);
1183 free(old);
1184 free(new);
1185 return;
1186 }
1187 new[nlen] = '\0';
1188
1189 char *oldc = canonify(old, &olen);
1190 char *newc = canonify(new, &nlen);
1191 if (!oldc || !newc) {
1192 ipc_answer_0(rid, EINVAL);
1193 free(old);
1194 free(new);
1195 return;
1196 }
1197 oldc[olen] = '\0';
1198 newc[nlen] = '\0';
1199 if ((!str_lcmp(newc, oldc, str_length(oldc))) &&
1200 ((newc[str_length(oldc)] == '/') ||
1201 (str_length(oldc) == 1) ||
1202 (str_length(oldc) == str_length(newc)))) {
1203 /*
1204 * oldc is a prefix of newc and either
1205 * - newc continues with a / where oldc ends, or
1206 * - oldc was / itself, or
1207 * - oldc and newc are equal.
1208 */
1209 ipc_answer_0(rid, EINVAL);
1210 free(old);
1211 free(new);
1212 return;
1213 }
1214
1215 vfs_lookup_res_t old_lr;
1216 vfs_lookup_res_t new_lr;
1217 vfs_lookup_res_t new_par_lr;
1218 fibril_rwlock_write_lock(&namespace_rwlock);
1219 /* Lookup the node belonging to the old file name. */
1220 rc = vfs_lookup_internal(oldc, L_NONE, &old_lr, NULL);
1221 if (rc != EOK) {
1222 fibril_rwlock_write_unlock(&namespace_rwlock);
1223 ipc_answer_0(rid, rc);
1224 free(old);
1225 free(new);
1226 return;
1227 }
1228 vfs_node_t *old_node = vfs_node_get(&old_lr);
1229 if (!old_node) {
1230 fibril_rwlock_write_unlock(&namespace_rwlock);
1231 ipc_answer_0(rid, ENOMEM);
1232 free(old);
1233 free(new);
1234 return;
1235 }
1236 /* Determine the path to the parent of the node with the new name. */
1237 char *parentc = str_dup(newc);
1238 if (!parentc) {
1239 fibril_rwlock_write_unlock(&namespace_rwlock);
1240 ipc_answer_0(rid, rc);
1241 free(old);
1242 free(new);
1243 return;
1244 }
1245 char *lastsl = str_rchr(parentc + 1, '/');
1246 if (lastsl)
1247 *lastsl = '\0';
1248 else
1249 parentc[1] = '\0';
1250 /* Lookup parent of the new file name. */
1251 rc = vfs_lookup_internal(parentc, L_NONE, &new_par_lr, NULL);
1252 free(parentc); /* not needed anymore */
1253 if (rc != EOK) {
1254 fibril_rwlock_write_unlock(&namespace_rwlock);
1255 ipc_answer_0(rid, rc);
1256 free(old);
1257 free(new);
1258 return;
1259 }
1260 /* Check whether linking to the same file system instance. */
1261 if ((old_node->fs_handle != new_par_lr.triplet.fs_handle) ||
1262 (old_node->dev_handle != new_par_lr.triplet.dev_handle)) {
1263 fibril_rwlock_write_unlock(&namespace_rwlock);
1264 ipc_answer_0(rid, EXDEV); /* different file systems */
1265 free(old);
1266 free(new);
1267 return;
1268 }
1269 /* Destroy the old link for the new name. */
1270 vfs_node_t *new_node = NULL;
1271 rc = vfs_lookup_internal(newc, L_UNLINK, &new_lr, NULL);
1272 switch (rc) {
1273 case ENOENT:
1274 /* simply not in our way */
1275 break;
1276 case EOK:
1277 new_node = vfs_node_get(&new_lr);
1278 if (!new_node) {
1279 fibril_rwlock_write_unlock(&namespace_rwlock);
1280 ipc_answer_0(rid, ENOMEM);
1281 free(old);
1282 free(new);
1283 return;
1284 }
1285 fibril_mutex_lock(&nodes_mutex);
1286 new_node->lnkcnt--;
1287 fibril_mutex_unlock(&nodes_mutex);
1288 break;
1289 default:
1290 fibril_rwlock_write_unlock(&namespace_rwlock);
1291 ipc_answer_0(rid, ENOTEMPTY);
1292 free(old);
1293 free(new);
1294 return;
1295 }
1296 /* Create the new link for the new name. */
1297 rc = vfs_lookup_internal(newc, L_LINK, NULL, NULL, old_node->index);
1298 if (rc != EOK) {
1299 fibril_rwlock_write_unlock(&namespace_rwlock);
1300 if (new_node)
1301 vfs_node_put(new_node);
1302 ipc_answer_0(rid, rc);
1303 free(old);
1304 free(new);
1305 return;
1306 }
1307 fibril_mutex_lock(&nodes_mutex);
1308 old_node->lnkcnt++;
1309 fibril_mutex_unlock(&nodes_mutex);
1310 /* Destroy the link for the old name. */
1311 rc = vfs_lookup_internal(oldc, L_UNLINK, NULL, NULL);
1312 if (rc != EOK) {
1313 fibril_rwlock_write_unlock(&namespace_rwlock);
1314 vfs_node_put(old_node);
1315 if (new_node)
1316 vfs_node_put(new_node);
1317 ipc_answer_0(rid, rc);
1318 free(old);
1319 free(new);
1320 return;
1321 }
1322 fibril_mutex_lock(&nodes_mutex);
1323 old_node->lnkcnt--;
1324 fibril_mutex_unlock(&nodes_mutex);
1325 fibril_rwlock_write_unlock(&namespace_rwlock);
1326 vfs_node_put(old_node);
1327 if (new_node)
1328 vfs_node_put(new_node);
1329 free(old);
1330 free(new);
1331 ipc_answer_0(rid, EOK);
1332}
1333
1334void vfs_dup(ipc_callid_t rid, ipc_call_t *request)
1335{
1336 int oldfd = IPC_GET_ARG1(*request);
1337 int newfd = IPC_GET_ARG2(*request);
1338
1339 /* Lookup the file structure corresponding to oldfd. */
1340 vfs_file_t *oldfile = vfs_file_get(oldfd);
1341 if (!oldfile) {
1342 ipc_answer_0(rid, EBADF);
1343 return;
1344 }
1345
1346 /* If the file descriptors are the same, do nothing. */
1347 if (oldfd == newfd) {
1348 ipc_answer_1(rid, EOK, newfd);
1349 return;
1350 }
1351
1352 /*
1353 * Lock the open file structure so that no other thread can manipulate
1354 * the same open file at a time.
1355 */
1356 fibril_mutex_lock(&oldfile->lock);
1357
1358 /* Lookup an open file structure possibly corresponding to newfd. */
1359 vfs_file_t *newfile = vfs_file_get(newfd);
1360 if (newfile) {
1361 /* Close the originally opened file. */
1362 int ret = vfs_close_internal(newfile);
1363 if (ret != EOK) {
1364 ipc_answer_0(rid, ret);
1365 return;
1366 }
1367
1368 ret = vfs_fd_free(newfd);
1369 if (ret != EOK) {
1370 ipc_answer_0(rid, ret);
1371 return;
1372 }
1373 }
1374
1375 /* Assign the old file to newfd. */
1376 int ret = vfs_fd_assign(oldfile, newfd);
1377 fibril_mutex_unlock(&oldfile->lock);
1378
1379 if (ret != EOK)
1380 ipc_answer_0(rid, ret);
1381 else
1382 ipc_answer_1(rid, EOK, newfd);
1383}
1384
1385/**
1386 * @}
1387 */
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