source: mainline/uspace/srv/vfs/vfs_ops.c@ 1993f9a

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 1993f9a was ec8bab59, checked in by Martin Decky <martin@…>, 16 years ago

remove superfluous variable
  • Property mode set to 100644
File size: 31.8 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_sync.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 = ipc_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 = ipc_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 (!ipc_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 = ipc_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 (!ipc_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 = ipc_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 (!ipc_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 = ipc_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_open(ipc_callid_t rid, ipc_call_t *request)
432{
433 if (!vfs_files_init()) {
434 ipc_answer_0(rid, ENOMEM);
435 return;
436 }
437
438 /*
439 * The POSIX interface is open(path, oflag, mode).
440 * We can receive oflags and mode along with the VFS_IN_OPEN call;
441 * the path will need to arrive in another call.
442 *
443 * We also receive one private, non-POSIX set of flags called lflag
444 * used to pass information to vfs_lookup_internal().
445 */
446 int lflag = IPC_GET_ARG1(*request);
447 int oflag = IPC_GET_ARG2(*request);
448 int mode = IPC_GET_ARG3(*request);
449 size_t len;
450
451 /* Ignore mode for now. */
452 (void) mode;
453
454 /*
455 * Make sure that we are called with exactly one of L_FILE and
456 * L_DIRECTORY. Make sure that the user does not pass L_OPEN.
457 */
458 if (((lflag & (L_FILE | L_DIRECTORY)) == 0) ||
459 ((lflag & (L_FILE | L_DIRECTORY)) == (L_FILE | L_DIRECTORY)) ||
460 ((lflag & L_OPEN) != 0)) {
461 ipc_answer_0(rid, EINVAL);
462 return;
463 }
464
465 if (oflag & O_CREAT)
466 lflag |= L_CREATE;
467 if (oflag & O_EXCL)
468 lflag |= L_EXCLUSIVE;
469
470 ipc_callid_t callid;
471 if (!ipc_data_write_receive(&callid, &len)) {
472 ipc_answer_0(callid, EINVAL);
473 ipc_answer_0(rid, EINVAL);
474 return;
475 }
476
477 char *path = malloc(len + 1);
478 if (!path) {
479 ipc_answer_0(callid, ENOMEM);
480 ipc_answer_0(rid, ENOMEM);
481 return;
482 }
483
484 int rc;
485 if ((rc = ipc_data_write_finalize(callid, path, len))) {
486 ipc_answer_0(rid, rc);
487 free(path);
488 return;
489 }
490 path[len] = '\0';
491
492 /*
493 * Avoid the race condition in which the file can be deleted before we
494 * find/create-and-lock the VFS node corresponding to the looked-up
495 * triplet.
496 */
497 if (lflag & L_CREATE)
498 fibril_rwlock_write_lock(&namespace_rwlock);
499 else
500 fibril_rwlock_read_lock(&namespace_rwlock);
501
502 /* The path is now populated and we can call vfs_lookup_internal(). */
503 vfs_lookup_res_t lr;
504 rc = vfs_lookup_internal(path, lflag | L_OPEN, &lr, NULL);
505 if (rc != EOK) {
506 if (lflag & L_CREATE)
507 fibril_rwlock_write_unlock(&namespace_rwlock);
508 else
509 fibril_rwlock_read_unlock(&namespace_rwlock);
510 ipc_answer_0(rid, rc);
511 free(path);
512 return;
513 }
514
515 /* Path is no longer needed. */
516 free(path);
517
518 vfs_node_t *node = vfs_node_get(&lr);
519 if (lflag & L_CREATE)
520 fibril_rwlock_write_unlock(&namespace_rwlock);
521 else
522 fibril_rwlock_read_unlock(&namespace_rwlock);
523
524 /* Truncate the file if requested and if necessary. */
525 if (oflag & O_TRUNC) {
526 fibril_rwlock_write_lock(&node->contents_rwlock);
527 if (node->size) {
528 rc = vfs_truncate_internal(node->fs_handle,
529 node->dev_handle, node->index, 0);
530 if (rc) {
531 fibril_rwlock_write_unlock(&node->contents_rwlock);
532 vfs_node_put(node);
533 ipc_answer_0(rid, rc);
534 return;
535 }
536 node->size = 0;
537 }
538 fibril_rwlock_write_unlock(&node->contents_rwlock);
539 }
540
541 /*
542 * Get ourselves a file descriptor and the corresponding vfs_file_t
543 * structure.
544 */
545 int fd = vfs_fd_alloc();
546 if (fd < 0) {
547 vfs_node_put(node);
548 ipc_answer_0(rid, fd);
549 return;
550 }
551 vfs_file_t *file = vfs_file_get(fd);
552 file->node = node;
553 if (oflag & O_APPEND)
554 file->append = true;
555
556 /*
557 * The following increase in reference count is for the fact that the
558 * file is being opened and that a file structure is pointing to it.
559 * It is necessary so that the file will not disappear when
560 * vfs_node_put() is called. The reference will be dropped by the
561 * respective VFS_IN_CLOSE.
562 */
563 vfs_node_addref(node);
564 vfs_node_put(node);
565
566 /* Success! Return the new file descriptor to the client. */
567 ipc_answer_1(rid, EOK, fd);
568}
569
570void vfs_open_node(ipc_callid_t rid, ipc_call_t *request)
571{
572 // FIXME: check for sanity of the supplied fs, dev and index
573
574 if (!vfs_files_init()) {
575 ipc_answer_0(rid, ENOMEM);
576 return;
577 }
578
579 /*
580 * The interface is open_node(fs, dev, index, oflag).
581 */
582 vfs_lookup_res_t lr;
583
584 lr.triplet.fs_handle = IPC_GET_ARG1(*request);
585 lr.triplet.dev_handle = IPC_GET_ARG2(*request);
586 lr.triplet.index = IPC_GET_ARG3(*request);
587 int oflag = IPC_GET_ARG4(*request);
588
589 fibril_rwlock_read_lock(&namespace_rwlock);
590
591 int rc = vfs_open_node_internal(&lr);
592 if (rc != EOK) {
593 fibril_rwlock_read_unlock(&namespace_rwlock);
594 ipc_answer_0(rid, rc);
595 return;
596 }
597
598 vfs_node_t *node = vfs_node_get(&lr);
599 fibril_rwlock_read_unlock(&namespace_rwlock);
600
601 /* Truncate the file if requested and if necessary. */
602 if (oflag & O_TRUNC) {
603 fibril_rwlock_write_lock(&node->contents_rwlock);
604 if (node->size) {
605 rc = vfs_truncate_internal(node->fs_handle,
606 node->dev_handle, node->index, 0);
607 if (rc) {
608 fibril_rwlock_write_unlock(&node->contents_rwlock);
609 vfs_node_put(node);
610 ipc_answer_0(rid, rc);
611 return;
612 }
613 node->size = 0;
614 }
615 fibril_rwlock_write_unlock(&node->contents_rwlock);
616 }
617
618 /*
619 * Get ourselves a file descriptor and the corresponding vfs_file_t
620 * structure.
621 */
622 int fd = vfs_fd_alloc();
623 if (fd < 0) {
624 vfs_node_put(node);
625 ipc_answer_0(rid, fd);
626 return;
627 }
628 vfs_file_t *file = vfs_file_get(fd);
629 file->node = node;
630 if (oflag & O_APPEND)
631 file->append = true;
632
633 /*
634 * The following increase in reference count is for the fact that the
635 * file is being opened and that a file structure is pointing to it.
636 * It is necessary so that the file will not disappear when
637 * vfs_node_put() is called. The reference will be dropped by the
638 * respective VFS_IN_CLOSE.
639 */
640 vfs_node_addref(node);
641 vfs_node_put(node);
642
643 /* Success! Return the new file descriptor to the client. */
644 ipc_answer_1(rid, EOK, fd);
645}
646
647void vfs_sync(ipc_callid_t rid, ipc_call_t *request)
648{
649 int fd = IPC_GET_ARG1(*request);
650
651 /* Lookup the file structure corresponding to the file descriptor. */
652 vfs_file_t *file = vfs_file_get(fd);
653 if (!file) {
654 ipc_answer_0(rid, ENOENT);
655 return;
656 }
657
658 /*
659 * Lock the open file structure so that no other thread can manipulate
660 * the same open file at a time.
661 */
662 fibril_mutex_lock(&file->lock);
663 int fs_phone = vfs_grab_phone(file->node->fs_handle);
664
665 /* Make a VFS_OUT_SYMC request at the destination FS server. */
666 aid_t msg;
667 ipc_call_t answer;
668 msg = async_send_2(fs_phone, VFS_OUT_SYNC, file->node->dev_handle,
669 file->node->index, &answer);
670
671 /* Wait for reply from the FS server. */
672 ipcarg_t rc;
673 async_wait_for(msg, &rc);
674
675 vfs_release_phone(fs_phone);
676 fibril_mutex_unlock(&file->lock);
677
678 ipc_answer_0(rid, rc);
679}
680
681void vfs_close(ipc_callid_t rid, ipc_call_t *request)
682{
683 int fd = IPC_GET_ARG1(*request);
684
685 /* Lookup the file structure corresponding to the file descriptor. */
686 vfs_file_t *file = vfs_file_get(fd);
687 if (!file) {
688 ipc_answer_0(rid, ENOENT);
689 return;
690 }
691
692 /*
693 * Lock the open file structure so that no other thread can manipulate
694 * the same open file at a time.
695 */
696 fibril_mutex_lock(&file->lock);
697 int fs_phone = vfs_grab_phone(file->node->fs_handle);
698
699 /* Make a VFS_OUT_CLOSE request at the destination FS server. */
700 aid_t msg;
701 ipc_call_t answer;
702 msg = async_send_2(fs_phone, VFS_OUT_CLOSE, file->node->dev_handle,
703 file->node->index, &answer);
704
705 /* Wait for reply from the FS server. */
706 ipcarg_t rc;
707 async_wait_for(msg, &rc);
708
709 vfs_release_phone(fs_phone);
710 fibril_mutex_unlock(&file->lock);
711
712 int retval = IPC_GET_ARG1(answer);
713 if (retval != EOK)
714 ipc_answer_0(rid, retval);
715
716 retval = vfs_fd_free(fd);
717 ipc_answer_0(rid, retval);
718}
719
720static void vfs_rdwr(ipc_callid_t rid, ipc_call_t *request, bool read)
721{
722
723 /*
724 * The following code strongly depends on the fact that the files data
725 * structure can be only accessed by a single fibril and all file
726 * operations are serialized (i.e. the reads and writes cannot
727 * interleave and a file cannot be closed while it is being read).
728 *
729 * Additional synchronization needs to be added once the table of
730 * open files supports parallel access!
731 */
732
733 int fd = IPC_GET_ARG1(*request);
734
735 /* Lookup the file structure corresponding to the file descriptor. */
736 vfs_file_t *file = vfs_file_get(fd);
737 if (!file) {
738 ipc_answer_0(rid, ENOENT);
739 return;
740 }
741
742 /*
743 * Now we need to receive a call with client's
744 * IPC_M_DATA_READ/IPC_M_DATA_WRITE request.
745 */
746 ipc_callid_t callid;
747 int res;
748 if (read)
749 res = ipc_data_read_receive(&callid, NULL);
750 else
751 res = ipc_data_write_receive(&callid, NULL);
752 if (!res) {
753 ipc_answer_0(callid, EINVAL);
754 ipc_answer_0(rid, EINVAL);
755 return;
756 }
757
758 /*
759 * Lock the open file structure so that no other thread can manipulate
760 * the same open file at a time.
761 */
762 fibril_mutex_lock(&file->lock);
763
764 /*
765 * Lock the file's node so that no other client can read/write to it at
766 * the same time.
767 */
768 if (read)
769 fibril_rwlock_read_lock(&file->node->contents_rwlock);
770 else
771 fibril_rwlock_write_lock(&file->node->contents_rwlock);
772
773 if (file->node->type == VFS_NODE_DIRECTORY) {
774 /*
775 * Make sure that no one is modifying the namespace
776 * while we are in readdir().
777 */
778 assert(read);
779 fibril_rwlock_read_lock(&namespace_rwlock);
780 }
781
782 int fs_phone = vfs_grab_phone(file->node->fs_handle);
783
784 /* Make a VFS_READ/VFS_WRITE request at the destination FS server. */
785 aid_t msg;
786 ipc_call_t answer;
787 if (!read && file->append)
788 file->pos = file->node->size;
789 msg = async_send_3(fs_phone, read ? VFS_OUT_READ : VFS_OUT_WRITE,
790 file->node->dev_handle, file->node->index, file->pos, &answer);
791
792 /*
793 * Forward the IPC_M_DATA_READ/IPC_M_DATA_WRITE request to the
794 * destination FS server. The call will be routed as if sent by
795 * ourselves. Note that call arguments are immutable in this case so we
796 * don't have to bother.
797 */
798 ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
799
800 /* Wait for reply from the FS server. */
801 ipcarg_t rc;
802 async_wait_for(msg, &rc);
803
804 vfs_release_phone(fs_phone);
805
806 size_t bytes = IPC_GET_ARG1(answer);
807
808 if (file->node->type == VFS_NODE_DIRECTORY)
809 fibril_rwlock_read_unlock(&namespace_rwlock);
810
811 /* Unlock the VFS node. */
812 if (read)
813 fibril_rwlock_read_unlock(&file->node->contents_rwlock);
814 else {
815 /* Update the cached version of node's size. */
816 if (rc == EOK)
817 file->node->size = IPC_GET_ARG2(answer);
818 fibril_rwlock_write_unlock(&file->node->contents_rwlock);
819 }
820
821 /* Update the position pointer and unlock the open file. */
822 if (rc == EOK)
823 file->pos += bytes;
824 fibril_mutex_unlock(&file->lock);
825
826 /*
827 * FS server's reply is the final result of the whole operation we
828 * return to the client.
829 */
830 ipc_answer_1(rid, rc, bytes);
831}
832
833void vfs_read(ipc_callid_t rid, ipc_call_t *request)
834{
835 vfs_rdwr(rid, request, true);
836}
837
838void vfs_write(ipc_callid_t rid, ipc_call_t *request)
839{
840 vfs_rdwr(rid, request, false);
841}
842
843void vfs_seek(ipc_callid_t rid, ipc_call_t *request)
844{
845 int fd = (int) IPC_GET_ARG1(*request);
846 off_t off = (off_t) IPC_GET_ARG2(*request);
847 int whence = (int) IPC_GET_ARG3(*request);
848
849
850 /* Lookup the file structure corresponding to the file descriptor. */
851 vfs_file_t *file = vfs_file_get(fd);
852 if (!file) {
853 ipc_answer_0(rid, ENOENT);
854 return;
855 }
856
857 off_t newpos;
858 fibril_mutex_lock(&file->lock);
859 if (whence == SEEK_SET) {
860 file->pos = off;
861 fibril_mutex_unlock(&file->lock);
862 ipc_answer_1(rid, EOK, off);
863 return;
864 }
865 if (whence == SEEK_CUR) {
866 if (file->pos + off < file->pos) {
867 fibril_mutex_unlock(&file->lock);
868 ipc_answer_0(rid, EOVERFLOW);
869 return;
870 }
871 file->pos += off;
872 newpos = file->pos;
873 fibril_mutex_unlock(&file->lock);
874 ipc_answer_1(rid, EOK, newpos);
875 return;
876 }
877 if (whence == SEEK_END) {
878 fibril_rwlock_read_lock(&file->node->contents_rwlock);
879 size_t size = file->node->size;
880 fibril_rwlock_read_unlock(&file->node->contents_rwlock);
881 if (size + off < size) {
882 fibril_mutex_unlock(&file->lock);
883 ipc_answer_0(rid, EOVERFLOW);
884 return;
885 }
886 newpos = size + off;
887 fibril_mutex_unlock(&file->lock);
888 ipc_answer_1(rid, EOK, newpos);
889 return;
890 }
891 fibril_mutex_unlock(&file->lock);
892 ipc_answer_0(rid, EINVAL);
893}
894
895int
896vfs_truncate_internal(fs_handle_t fs_handle, dev_handle_t dev_handle,
897 fs_index_t index, size_t size)
898{
899 ipcarg_t rc;
900 int fs_phone;
901
902 fs_phone = vfs_grab_phone(fs_handle);
903 rc = async_req_3_0(fs_phone, VFS_OUT_TRUNCATE, (ipcarg_t)dev_handle,
904 (ipcarg_t)index, (ipcarg_t)size);
905 vfs_release_phone(fs_phone);
906 return (int)rc;
907}
908
909void vfs_truncate(ipc_callid_t rid, ipc_call_t *request)
910{
911 int fd = IPC_GET_ARG1(*request);
912 size_t size = IPC_GET_ARG2(*request);
913 int rc;
914
915 vfs_file_t *file = vfs_file_get(fd);
916 if (!file) {
917 ipc_answer_0(rid, ENOENT);
918 return;
919 }
920 fibril_mutex_lock(&file->lock);
921
922 fibril_rwlock_write_lock(&file->node->contents_rwlock);
923 rc = vfs_truncate_internal(file->node->fs_handle,
924 file->node->dev_handle, file->node->index, size);
925 if (rc == EOK)
926 file->node->size = size;
927 fibril_rwlock_write_unlock(&file->node->contents_rwlock);
928
929 fibril_mutex_unlock(&file->lock);
930 ipc_answer_0(rid, (ipcarg_t)rc);
931}
932
933void vfs_fstat(ipc_callid_t rid, ipc_call_t *request)
934{
935 int fd = IPC_GET_ARG1(*request);
936 ipcarg_t rc;
937
938 vfs_file_t *file = vfs_file_get(fd);
939 if (!file) {
940 ipc_answer_0(rid, ENOENT);
941 return;
942 }
943
944 ipc_callid_t callid;
945 if (!ipc_data_read_receive(&callid, NULL)) {
946 ipc_answer_0(callid, EINVAL);
947 ipc_answer_0(rid, EINVAL);
948 return;
949 }
950
951 fibril_mutex_lock(&file->lock);
952
953 int fs_phone = vfs_grab_phone(file->node->fs_handle);
954
955 aid_t msg;
956 msg = async_send_3(fs_phone, VFS_OUT_STAT, file->node->dev_handle,
957 file->node->index, true, NULL);
958 ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
959 async_wait_for(msg, &rc);
960 vfs_release_phone(fs_phone);
961
962 fibril_mutex_unlock(&file->lock);
963 ipc_answer_0(rid, rc);
964}
965
966void vfs_stat(ipc_callid_t rid, ipc_call_t *request)
967{
968 size_t len;
969 ipc_callid_t callid;
970
971 if (!ipc_data_write_receive(&callid, &len)) {
972 ipc_answer_0(callid, EINVAL);
973 ipc_answer_0(rid, EINVAL);
974 return;
975 }
976 char *path = malloc(len + 1);
977 if (!path) {
978 ipc_answer_0(callid, ENOMEM);
979 ipc_answer_0(rid, ENOMEM);
980 return;
981 }
982 int rc;
983 if ((rc = ipc_data_write_finalize(callid, path, len))) {
984 ipc_answer_0(rid, rc);
985 free(path);
986 return;
987 }
988 path[len] = '\0';
989
990 if (!ipc_data_read_receive(&callid, NULL)) {
991 free(path);
992 ipc_answer_0(callid, EINVAL);
993 ipc_answer_0(rid, EINVAL);
994 return;
995 }
996
997 vfs_lookup_res_t lr;
998 fibril_rwlock_read_lock(&namespace_rwlock);
999 rc = vfs_lookup_internal(path, L_NONE, &lr, NULL);
1000 free(path);
1001 if (rc != EOK) {
1002 fibril_rwlock_read_unlock(&namespace_rwlock);
1003 ipc_answer_0(callid, rc);
1004 ipc_answer_0(rid, rc);
1005 return;
1006 }
1007 vfs_node_t *node = vfs_node_get(&lr);
1008 if (!node) {
1009 fibril_rwlock_read_unlock(&namespace_rwlock);
1010 ipc_answer_0(callid, ENOMEM);
1011 ipc_answer_0(rid, ENOMEM);
1012 return;
1013 }
1014
1015 fibril_rwlock_read_unlock(&namespace_rwlock);
1016
1017 int fs_phone = vfs_grab_phone(node->fs_handle);
1018 aid_t msg;
1019 msg = async_send_3(fs_phone, VFS_OUT_STAT, node->dev_handle,
1020 node->index, false, NULL);
1021 ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
1022
1023 ipcarg_t rv;
1024 async_wait_for(msg, &rv);
1025 vfs_release_phone(fs_phone);
1026
1027 ipc_answer_0(rid, rv);
1028
1029 vfs_node_put(node);
1030}
1031
1032void vfs_mkdir(ipc_callid_t rid, ipc_call_t *request)
1033{
1034 int mode = IPC_GET_ARG1(*request);
1035
1036 size_t len;
1037 ipc_callid_t callid;
1038
1039 if (!ipc_data_write_receive(&callid, &len)) {
1040 ipc_answer_0(callid, EINVAL);
1041 ipc_answer_0(rid, EINVAL);
1042 return;
1043 }
1044 char *path = malloc(len + 1);
1045 if (!path) {
1046 ipc_answer_0(callid, ENOMEM);
1047 ipc_answer_0(rid, ENOMEM);
1048 return;
1049 }
1050 int rc;
1051 if ((rc = ipc_data_write_finalize(callid, path, len))) {
1052 ipc_answer_0(rid, rc);
1053 free(path);
1054 return;
1055 }
1056 path[len] = '\0';
1057
1058 /* Ignore mode for now. */
1059 (void) mode;
1060
1061 fibril_rwlock_write_lock(&namespace_rwlock);
1062 int lflag = L_DIRECTORY | L_CREATE | L_EXCLUSIVE;
1063 rc = vfs_lookup_internal(path, lflag, NULL, NULL);
1064 fibril_rwlock_write_unlock(&namespace_rwlock);
1065 free(path);
1066 ipc_answer_0(rid, rc);
1067}
1068
1069void vfs_unlink(ipc_callid_t rid, ipc_call_t *request)
1070{
1071 int lflag = IPC_GET_ARG1(*request);
1072
1073 size_t len;
1074 ipc_callid_t callid;
1075
1076 if (!ipc_data_write_receive(&callid, &len)) {
1077 ipc_answer_0(callid, EINVAL);
1078 ipc_answer_0(rid, EINVAL);
1079 return;
1080 }
1081 char *path = malloc(len + 1);
1082 if (!path) {
1083 ipc_answer_0(callid, ENOMEM);
1084 ipc_answer_0(rid, ENOMEM);
1085 return;
1086 }
1087 int rc;
1088 if ((rc = ipc_data_write_finalize(callid, path, len))) {
1089 ipc_answer_0(rid, rc);
1090 free(path);
1091 return;
1092 }
1093 path[len] = '\0';
1094
1095 fibril_rwlock_write_lock(&namespace_rwlock);
1096 lflag &= L_DIRECTORY; /* sanitize lflag */
1097 vfs_lookup_res_t lr;
1098 rc = vfs_lookup_internal(path, lflag | L_UNLINK, &lr, NULL);
1099 free(path);
1100 if (rc != EOK) {
1101 fibril_rwlock_write_unlock(&namespace_rwlock);
1102 ipc_answer_0(rid, rc);
1103 return;
1104 }
1105
1106 /*
1107 * The name has already been unlinked by vfs_lookup_internal().
1108 * We have to get and put the VFS node to ensure that it is
1109 * VFS_OUT_DESTROY'ed after the last reference to it is dropped.
1110 */
1111 vfs_node_t *node = vfs_node_get(&lr);
1112 fibril_mutex_lock(&nodes_mutex);
1113 node->lnkcnt--;
1114 fibril_mutex_unlock(&nodes_mutex);
1115 fibril_rwlock_write_unlock(&namespace_rwlock);
1116 vfs_node_put(node);
1117 ipc_answer_0(rid, EOK);
1118}
1119
1120void vfs_rename(ipc_callid_t rid, ipc_call_t *request)
1121{
1122 size_t olen, nlen;
1123 ipc_callid_t callid;
1124 int rc;
1125
1126 /* Retrieve the old path. */
1127 if (!ipc_data_write_receive(&callid, &olen)) {
1128 ipc_answer_0(callid, EINVAL);
1129 ipc_answer_0(rid, EINVAL);
1130 return;
1131 }
1132 char *old = malloc(olen + 1);
1133 if (!old) {
1134 ipc_answer_0(callid, ENOMEM);
1135 ipc_answer_0(rid, ENOMEM);
1136 return;
1137 }
1138 if ((rc = ipc_data_write_finalize(callid, old, olen))) {
1139 ipc_answer_0(rid, rc);
1140 free(old);
1141 return;
1142 }
1143 old[olen] = '\0';
1144
1145 /* Retrieve the new path. */
1146 if (!ipc_data_write_receive(&callid, &nlen)) {
1147 ipc_answer_0(callid, EINVAL);
1148 ipc_answer_0(rid, EINVAL);
1149 free(old);
1150 return;
1151 }
1152 char *new = malloc(nlen + 1);
1153 if (!new) {
1154 ipc_answer_0(callid, ENOMEM);
1155 ipc_answer_0(rid, ENOMEM);
1156 free(old);
1157 return;
1158 }
1159 if ((rc = ipc_data_write_finalize(callid, new, nlen))) {
1160 ipc_answer_0(rid, rc);
1161 free(old);
1162 free(new);
1163 return;
1164 }
1165 new[nlen] = '\0';
1166
1167 char *oldc = canonify(old, &olen);
1168 char *newc = canonify(new, &nlen);
1169 if (!oldc || !newc) {
1170 ipc_answer_0(rid, EINVAL);
1171 free(old);
1172 free(new);
1173 return;
1174 }
1175 oldc[olen] = '\0';
1176 newc[nlen] = '\0';
1177 if ((!str_lcmp(newc, oldc, str_length(oldc))) &&
1178 ((newc[str_length(oldc)] == '/') ||
1179 (str_length(oldc) == 1) ||
1180 (str_length(oldc) == str_length(newc)))) {
1181 /*
1182 * oldc is a prefix of newc and either
1183 * - newc continues with a / where oldc ends, or
1184 * - oldc was / itself, or
1185 * - oldc and newc are equal.
1186 */
1187 ipc_answer_0(rid, EINVAL);
1188 free(old);
1189 free(new);
1190 return;
1191 }
1192
1193 vfs_lookup_res_t old_lr;
1194 vfs_lookup_res_t new_lr;
1195 vfs_lookup_res_t new_par_lr;
1196 fibril_rwlock_write_lock(&namespace_rwlock);
1197 /* Lookup the node belonging to the old file name. */
1198 rc = vfs_lookup_internal(oldc, L_NONE, &old_lr, NULL);
1199 if (rc != EOK) {
1200 fibril_rwlock_write_unlock(&namespace_rwlock);
1201 ipc_answer_0(rid, rc);
1202 free(old);
1203 free(new);
1204 return;
1205 }
1206 vfs_node_t *old_node = vfs_node_get(&old_lr);
1207 if (!old_node) {
1208 fibril_rwlock_write_unlock(&namespace_rwlock);
1209 ipc_answer_0(rid, ENOMEM);
1210 free(old);
1211 free(new);
1212 return;
1213 }
1214 /* Determine the path to the parent of the node with the new name. */
1215 char *parentc = str_dup(newc);
1216 if (!parentc) {
1217 fibril_rwlock_write_unlock(&namespace_rwlock);
1218 ipc_answer_0(rid, rc);
1219 free(old);
1220 free(new);
1221 return;
1222 }
1223 char *lastsl = str_rchr(parentc + 1, '/');
1224 if (lastsl)
1225 *lastsl = '\0';
1226 else
1227 parentc[1] = '\0';
1228 /* Lookup parent of the new file name. */
1229 rc = vfs_lookup_internal(parentc, L_NONE, &new_par_lr, NULL);
1230 free(parentc); /* not needed anymore */
1231 if (rc != EOK) {
1232 fibril_rwlock_write_unlock(&namespace_rwlock);
1233 ipc_answer_0(rid, rc);
1234 free(old);
1235 free(new);
1236 return;
1237 }
1238 /* Check whether linking to the same file system instance. */
1239 if ((old_node->fs_handle != new_par_lr.triplet.fs_handle) ||
1240 (old_node->dev_handle != new_par_lr.triplet.dev_handle)) {
1241 fibril_rwlock_write_unlock(&namespace_rwlock);
1242 ipc_answer_0(rid, EXDEV); /* different file systems */
1243 free(old);
1244 free(new);
1245 return;
1246 }
1247 /* Destroy the old link for the new name. */
1248 vfs_node_t *new_node = NULL;
1249 rc = vfs_lookup_internal(newc, L_UNLINK, &new_lr, NULL);
1250 switch (rc) {
1251 case ENOENT:
1252 /* simply not in our way */
1253 break;
1254 case EOK:
1255 new_node = vfs_node_get(&new_lr);
1256 if (!new_node) {
1257 fibril_rwlock_write_unlock(&namespace_rwlock);
1258 ipc_answer_0(rid, ENOMEM);
1259 free(old);
1260 free(new);
1261 return;
1262 }
1263 fibril_mutex_lock(&nodes_mutex);
1264 new_node->lnkcnt--;
1265 fibril_mutex_unlock(&nodes_mutex);
1266 break;
1267 default:
1268 fibril_rwlock_write_unlock(&namespace_rwlock);
1269 ipc_answer_0(rid, ENOTEMPTY);
1270 free(old);
1271 free(new);
1272 return;
1273 }
1274 /* Create the new link for the new name. */
1275 rc = vfs_lookup_internal(newc, L_LINK, NULL, NULL, old_node->index);
1276 if (rc != EOK) {
1277 fibril_rwlock_write_unlock(&namespace_rwlock);
1278 if (new_node)
1279 vfs_node_put(new_node);
1280 ipc_answer_0(rid, rc);
1281 free(old);
1282 free(new);
1283 return;
1284 }
1285 fibril_mutex_lock(&nodes_mutex);
1286 old_node->lnkcnt++;
1287 fibril_mutex_unlock(&nodes_mutex);
1288 /* Destroy the link for the old name. */
1289 rc = vfs_lookup_internal(oldc, L_UNLINK, NULL, NULL);
1290 if (rc != EOK) {
1291 fibril_rwlock_write_unlock(&namespace_rwlock);
1292 vfs_node_put(old_node);
1293 if (new_node)
1294 vfs_node_put(new_node);
1295 ipc_answer_0(rid, rc);
1296 free(old);
1297 free(new);
1298 return;
1299 }
1300 fibril_mutex_lock(&nodes_mutex);
1301 old_node->lnkcnt--;
1302 fibril_mutex_unlock(&nodes_mutex);
1303 fibril_rwlock_write_unlock(&namespace_rwlock);
1304 vfs_node_put(old_node);
1305 if (new_node)
1306 vfs_node_put(new_node);
1307 free(old);
1308 free(new);
1309 ipc_answer_0(rid, EOK);
1310}
1311
1312/**
1313 * @}
1314 */
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