source: mainline/uspace/srv/vfs/vfs_ops.c@ fa5526d

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since fa5526d was 057760d3, checked in by Martin Decky <martin@…>, 16 years ago

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