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4419 trochtova 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    fat_ops.c
35
 * @brief   Implementation of VFS operations for the FAT file system server.
36
 */
37
 
38
#include "fat.h"
39
#include "fat_dentry.h"
40
#include "fat_fat.h"
41
#include "../../vfs/vfs.h"
42
#include <libfs.h>
43
#include <libblock.h>
44
#include <ipc/ipc.h>
45
#include <ipc/services.h>
46
#include <ipc/devmap.h>
47
#include <async.h>
48
#include <errno.h>
49
#include <string.h>
50
#include <byteorder.h>
51
#include <libadt/hash_table.h>
52
#include <libadt/list.h>
53
#include <assert.h>
54
#include <futex.h>
55
#include <sys/mman.h>
56
#include <align.h>
57
 
58
/** Futex protecting the list of cached free FAT nodes. */
59
static futex_t ffn_futex = FUTEX_INITIALIZER;
60
 
61
/** List of cached free FAT nodes. */
62
static LIST_INITIALIZE(ffn_head);
63
 
64
static void fat_node_initialize(fat_node_t *node)
65
{
66
    futex_initialize(&node->lock, 1);
67
    node->idx = NULL;
68
    node->type = 0;
69
    link_initialize(&node->ffn_link);
70
    node->size = 0;
71
    node->lnkcnt = 0;
72
    node->refcnt = 0;
73
    node->dirty = false;
74
}
75
 
76
static void fat_node_sync(fat_node_t *node)
77
{
78
    block_t *b;
79
    fat_bs_t *bs;
80
    fat_dentry_t *d;
81
    uint16_t bps;
82
    unsigned dps;
83
 
84
    assert(node->dirty);
85
 
86
    bs = block_bb_get(node->idx->dev_handle);
87
    bps = uint16_t_le2host(bs->bps);
88
    dps = bps / sizeof(fat_dentry_t);
89
 
90
    /* Read the block that contains the dentry of interest. */
91
    b = _fat_block_get(bs, node->idx->dev_handle, node->idx->pfc,
92
        (node->idx->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
93
 
94
    d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps);
95
 
96
    d->firstc = host2uint16_t_le(node->firstc);
97
    if (node->type == FAT_FILE) {
98
        d->size = host2uint32_t_le(node->size);
99
    } else if (node->type == FAT_DIRECTORY) {
100
        d->attr = FAT_ATTR_SUBDIR;
101
    }
102
 
103
    /* TODO: update other fields? (e.g time fields) */
104
 
105
    b->dirty = true;        /* need to sync block */
106
    block_put(b);
107
}
108
 
109
static fat_node_t *fat_node_get_new(void)
110
{
111
    fat_node_t *nodep;
112
 
113
    futex_down(&ffn_futex);
114
    if (!list_empty(&ffn_head)) {
115
        /* Try to use a cached free node structure. */
116
        fat_idx_t *idxp_tmp;
117
        nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
118
        if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
119
            goto skip_cache;
120
        idxp_tmp = nodep->idx;
121
        if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
122
            futex_up(&nodep->lock);
123
            goto skip_cache;
124
        }
125
        list_remove(&nodep->ffn_link);
126
        futex_up(&ffn_futex);
127
        if (nodep->dirty)
128
            fat_node_sync(nodep);
129
        idxp_tmp->nodep = NULL;
130
        futex_up(&nodep->lock);
131
        futex_up(&idxp_tmp->lock);
132
    } else {
133
skip_cache:
134
        /* Try to allocate a new node structure. */
135
        futex_up(&ffn_futex);
136
        nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
137
        if (!nodep)
138
            return NULL;
139
    }
140
    fat_node_initialize(nodep);
141
 
142
    return nodep;
143
}
144
 
145
/** Internal version of fat_node_get().
146
 *
147
 * @param idxp      Locked index structure.
148
 */
149
static void *fat_node_get_core(fat_idx_t *idxp)
150
{
151
    block_t *b;
152
    fat_bs_t *bs;
153
    fat_dentry_t *d;
154
    fat_node_t *nodep = NULL;
155
    unsigned bps;
156
    unsigned spc;
157
    unsigned dps;
158
 
159
    if (idxp->nodep) {
160
        /*
161
         * We are lucky.
162
         * The node is already instantiated in memory.
163
         */
164
        futex_down(&idxp->nodep->lock);
165
        if (!idxp->nodep->refcnt++)
166
            list_remove(&idxp->nodep->ffn_link);
167
        futex_up(&idxp->nodep->lock);
168
        return idxp->nodep;
169
    }
170
 
171
    /*
172
     * We must instantiate the node from the file system.
173
     */
174
 
175
    assert(idxp->pfc);
176
 
177
    nodep = fat_node_get_new();
178
    if (!nodep)
179
        return NULL;
180
 
181
    bs = block_bb_get(idxp->dev_handle);
182
    bps = uint16_t_le2host(bs->bps);
183
    spc = bs->spc;
184
    dps = bps / sizeof(fat_dentry_t);
185
 
186
    /* Read the block that contains the dentry of interest. */
187
    b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc,
188
        (idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
189
    assert(b);
190
 
191
    d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
192
    if (d->attr & FAT_ATTR_SUBDIR) {
193
        /*
194
         * The only directory which does not have this bit set is the
195
         * root directory itself. The root directory node is handled
196
         * and initialized elsewhere.
197
         */
198
        nodep->type = FAT_DIRECTORY;
199
        /*
200
         * Unfortunately, the 'size' field of the FAT dentry is not
201
         * defined for the directory entry type. We must determine the
202
         * size of the directory by walking the FAT.
203
         */
204
        nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle,
205
            uint16_t_le2host(d->firstc));
206
    } else {
207
        nodep->type = FAT_FILE;
208
        nodep->size = uint32_t_le2host(d->size);
209
    }
210
    nodep->firstc = uint16_t_le2host(d->firstc);
211
    nodep->lnkcnt = 1;
212
    nodep->refcnt = 1;
213
 
214
    block_put(b);
215
 
216
    /* Link the idx structure with the node structure. */
217
    nodep->idx = idxp;
218
    idxp->nodep = nodep;
219
 
220
    return nodep;
221
}
222
 
223
/*
224
 * Forward declarations of FAT libfs operations.
225
 */
226
static void *fat_node_get(dev_handle_t, fs_index_t);
227
static void fat_node_put(void *);
228
static void *fat_create_node(dev_handle_t, int);
229
static int fat_destroy_node(void *);
230
static int fat_link(void *, void *, const char *);
231
static int fat_unlink(void *, void *);
232
static void *fat_match(void *, const char *);
233
static fs_index_t fat_index_get(void *);
234
static size_t fat_size_get(void *);
235
static unsigned fat_lnkcnt_get(void *);
236
static bool fat_has_children(void *);
237
static void *fat_root_get(dev_handle_t);
238
static char fat_plb_get_char(unsigned);
239
static bool fat_is_directory(void *);
240
static bool fat_is_file(void *node);
241
 
242
/*
243
 * FAT libfs operations.
244
 */
245
 
246
/** Instantiate a FAT in-core node. */
247
void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
248
{
249
    void *node;
250
    fat_idx_t *idxp;
251
 
252
    idxp = fat_idx_get_by_index(dev_handle, index);
253
    if (!idxp)
254
        return NULL;
255
    /* idxp->lock held */
256
    node = fat_node_get_core(idxp);
257
    futex_up(&idxp->lock);
258
    return node;
259
}
260
 
261
void fat_node_put(void *node)
262
{
263
    fat_node_t *nodep = (fat_node_t *)node;
264
    bool destroy = false;
265
 
266
    futex_down(&nodep->lock);
267
    if (!--nodep->refcnt) {
268
        if (nodep->idx) {
269
            futex_down(&ffn_futex);
270
            list_append(&nodep->ffn_link, &ffn_head);
271
            futex_up(&ffn_futex);
272
        } else {
273
            /*
274
             * The node does not have any index structure associated
275
             * with itself. This can only mean that we are releasing
276
             * the node after a failed attempt to allocate the index
277
             * structure for it.
278
             */
279
            destroy = true;
280
        }
281
    }
282
    futex_up(&nodep->lock);
283
    if (destroy)
284
        free(node);
285
}
286
 
287
void *fat_create_node(dev_handle_t dev_handle, int flags)
288
{
289
    fat_idx_t *idxp;
290
    fat_node_t *nodep;
291
    fat_bs_t *bs;
292
    fat_cluster_t mcl, lcl;
293
    uint16_t bps;
294
    int rc;
295
 
296
    bs = block_bb_get(dev_handle);
297
    bps = uint16_t_le2host(bs->bps);
298
    if (flags & L_DIRECTORY) {
299
        /* allocate a cluster */
300
        rc = fat_alloc_clusters(bs, dev_handle, 1, &mcl, &lcl);
301
        if (rc != EOK)
302
            return NULL;
303
    }
304
 
305
    nodep = fat_node_get_new();
306
    if (!nodep) {
307
        fat_free_clusters(bs, dev_handle, mcl);
308
        return NULL;
309
    }
310
    idxp = fat_idx_get_new(dev_handle);
311
    if (!idxp) {
312
        fat_free_clusters(bs, dev_handle, mcl);
313
        fat_node_put(nodep);
314
        return NULL;
315
    }
316
    /* idxp->lock held */
317
    if (flags & L_DIRECTORY) {
318
        int i;
319
        block_t *b;
320
 
321
        /*
322
         * Populate the new cluster with unused dentries.
323
         */
324
        for (i = 0; i < bs->spc; i++) {
325
            b = _fat_block_get(bs, dev_handle, mcl, i,
326
                BLOCK_FLAGS_NOREAD);
327
            /* mark all dentries as never-used */
328
            memset(b->data, 0, bps);
329
            b->dirty = false;
330
            block_put(b);
331
        }
332
        nodep->type = FAT_DIRECTORY;
333
        nodep->firstc = mcl;
334
        nodep->size = bps * bs->spc;
335
    } else {
336
        nodep->type = FAT_FILE;
337
        nodep->firstc = FAT_CLST_RES0;
338
        nodep->size = 0;
339
    }
340
    nodep->lnkcnt = 0;  /* not linked anywhere */
341
    nodep->refcnt = 1;
342
    nodep->dirty = true;
343
 
344
    nodep->idx = idxp;
345
    idxp->nodep = nodep;
346
 
347
    futex_up(&idxp->lock);
348
    return nodep;
349
}
350
 
351
int fat_destroy_node(void *node)
352
{
353
    fat_node_t *nodep = (fat_node_t *)node;
354
    fat_bs_t *bs;
355
 
356
    /*
357
     * The node is not reachable from the file system. This means that the
358
     * link count should be zero and that the index structure cannot be
359
     * found in the position hash. Obviously, we don't need to lock the node
360
     * nor its index structure.
361
     */
362
    assert(nodep->lnkcnt == 0);
363
 
364
    /*
365
     * The node may not have any children.
366
     */
367
    assert(fat_has_children(node) == false);
368
 
369
    bs = block_bb_get(nodep->idx->dev_handle);
370
    if (nodep->firstc != FAT_CLST_RES0) {
371
        assert(nodep->size);
372
        /* Free all clusters allocated to the node. */
373
        fat_free_clusters(bs, nodep->idx->dev_handle, nodep->firstc);
374
    }
375
 
376
    fat_idx_destroy(nodep->idx);
377
    free(nodep);
378
    return EOK;
379
}
380
 
381
int fat_link(void *prnt, void *chld, const char *name)
382
{
383
    fat_node_t *parentp = (fat_node_t *)prnt;
384
    fat_node_t *childp = (fat_node_t *)chld;
385
    fat_dentry_t *d;
386
    fat_bs_t *bs;
387
    block_t *b;
388
    int i, j;
389
    uint16_t bps;
390
    unsigned dps;
391
    unsigned blocks;
392
    fat_cluster_t mcl, lcl;
393
    int rc;
394
 
395
    futex_down(&childp->lock);
396
    if (childp->lnkcnt == 1) {
397
        /*
398
         * On FAT, we don't support multiple hard links.
399
         */
400
        futex_up(&childp->lock);
401
        return EMLINK;
402
    }
403
    assert(childp->lnkcnt == 0);
404
    futex_up(&childp->lock);
405
 
406
    if (!fat_dentry_name_verify(name)) {
407
        /*
408
         * Attempt to create unsupported name.
409
         */
410
        return ENOTSUP;
411
    }
412
 
413
    /*
414
     * Get us an unused parent node's dentry or grow the parent and allocate
415
     * a new one.
416
     */
417
 
418
    futex_down(&parentp->idx->lock);
419
    bs = block_bb_get(parentp->idx->dev_handle);
420
    bps = uint16_t_le2host(bs->bps);
421
    dps = bps / sizeof(fat_dentry_t);
422
 
423
    blocks = parentp->size / bps;
424
 
425
    for (i = 0; i < blocks; i++) {
426
        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
427
        for (j = 0; j < dps; j++) {
428
            d = ((fat_dentry_t *)b->data) + j;
429
            switch (fat_classify_dentry(d)) {
430
            case FAT_DENTRY_SKIP:
431
            case FAT_DENTRY_VALID:
432
                /* skipping used and meta entries */
433
                continue;
434
            case FAT_DENTRY_FREE:
435
            case FAT_DENTRY_LAST:
436
                /* found an empty slot */
437
                goto hit;
438
            }
439
        }
440
        block_put(b);
441
    }
442
    j = 0;
443
 
444
    /*
445
     * We need to grow the parent in order to create a new unused dentry.
446
     */
447
    if (parentp->idx->pfc == FAT_CLST_ROOT) {
448
        /* Can't grow the root directory. */
449
        futex_up(&parentp->idx->lock);
450
        return ENOSPC;
451
    }
452
    rc = fat_alloc_clusters(bs, parentp->idx->dev_handle, 1, &mcl, &lcl);
453
    if (rc != EOK) {
454
        futex_up(&parentp->idx->lock);
455
        return rc;
456
    }
457
    fat_append_clusters(bs, parentp, mcl);
458
    b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NOREAD);
459
    d = (fat_dentry_t *)b->data;
460
    /*
461
     * Clear all dentries in the block except for the first one (the first
462
     * dentry will be cleared in the next step).
463
     */
464
    memset(d + 1, 0, bps - sizeof(fat_dentry_t));
465
 
466
hit:
467
    /*
468
     * At this point we only establish the link between the parent and the
469
     * child.  The dentry, except of the name and the extension, will remain
470
     * uninitialized until the corresponding node is synced. Thus the valid
471
     * dentry data is kept in the child node structure.
472
     */
473
    memset(d, 0, sizeof(fat_dentry_t));
474
    fat_dentry_name_set(d, name);
475
    b->dirty = true;        /* need to sync block */
476
    block_put(b);
477
    futex_up(&parentp->idx->lock);
478
 
479
    futex_down(&childp->idx->lock);
480
 
481
    /*
482
     * If possible, create the Sub-directory Identifier Entry and the
483
     * Sub-directory Parent Pointer Entry (i.e. "." and ".."). These entries
484
     * are not mandatory according to Standard ECMA-107 and HelenOS VFS does
485
     * not use them anyway, so this is rather a sign of our good will.
486
     */
487
    b = fat_block_get(bs, childp, 0, BLOCK_FLAGS_NONE);
488
    d = (fat_dentry_t *)b->data;
489
    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
490
        str_cmp(d->name, FAT_NAME_DOT) == 0) {
491
        memset(d, 0, sizeof(fat_dentry_t));
492
        str_cpy(d->name, 8, FAT_NAME_DOT);
493
        str_cpy(d->ext, 3, FAT_EXT_PAD);
494
        d->attr = FAT_ATTR_SUBDIR;
495
        d->firstc = host2uint16_t_le(childp->firstc);
496
        /* TODO: initialize also the date/time members. */
497
    }
498
    d++;
499
    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
500
        str_cmp(d->name, FAT_NAME_DOT_DOT) == 0) {
501
        memset(d, 0, sizeof(fat_dentry_t));
502
        str_cpy(d->name, 8, FAT_NAME_DOT_DOT);
503
        str_cpy(d->ext, 3, FAT_EXT_PAD);
504
        d->attr = FAT_ATTR_SUBDIR;
505
        d->firstc = (parentp->firstc == FAT_CLST_ROOT) ?
506
            host2uint16_t_le(FAT_CLST_RES0) :
507
            host2uint16_t_le(parentp->firstc);
508
        /* TODO: initialize also the date/time members. */
509
    }
510
    b->dirty = true;        /* need to sync block */
511
    block_put(b);
512
 
513
    childp->idx->pfc = parentp->firstc;
514
    childp->idx->pdi = i * dps + j;
515
    futex_up(&childp->idx->lock);
516
 
517
    futex_down(&childp->lock);
518
    childp->lnkcnt = 1;
519
    childp->dirty = true;       /* need to sync node */
520
    futex_up(&childp->lock);
521
 
522
    /*
523
     * Hash in the index structure into the position hash.
524
     */
525
    fat_idx_hashin(childp->idx);
526
 
527
    return EOK;
528
}
529
 
530
int fat_unlink(void *prnt, void *chld)
531
{
532
    fat_node_t *parentp = (fat_node_t *)prnt;
533
    fat_node_t *childp = (fat_node_t *)chld;
534
    fat_bs_t *bs;
535
    fat_dentry_t *d;
536
    uint16_t bps;
537
    block_t *b;
538
 
539
    futex_down(&parentp->lock);
540
    futex_down(&childp->lock);
541
    assert(childp->lnkcnt == 1);
542
    futex_down(&childp->idx->lock);
543
    bs = block_bb_get(childp->idx->dev_handle);
544
    bps = uint16_t_le2host(bs->bps);
545
 
546
    b = _fat_block_get(bs, childp->idx->dev_handle, childp->idx->pfc,
547
        (childp->idx->pdi * sizeof(fat_dentry_t)) / bps,
548
        BLOCK_FLAGS_NONE);
549
    d = (fat_dentry_t *)b->data +
550
        (childp->idx->pdi % (bps / sizeof(fat_dentry_t)));
551
    /* mark the dentry as not-currently-used */
552
    d->name[0] = FAT_DENTRY_ERASED;
553
    b->dirty = true;        /* need to sync block */
554
    block_put(b);
555
 
556
    /* remove the index structure from the position hash */
557
    fat_idx_hashout(childp->idx);
558
    /* clear position information */
559
    childp->idx->pfc = FAT_CLST_RES0;
560
    childp->idx->pdi = 0;
561
    futex_up(&childp->idx->lock);
562
    childp->lnkcnt = 0;
563
    childp->dirty = true;
564
    futex_up(&childp->lock);
565
    futex_up(&parentp->lock);
566
 
567
    return EOK;
568
}
569
 
570
void *fat_match(void *prnt, const char *component)
571
{
572
    fat_bs_t *bs;
573
    fat_node_t *parentp = (fat_node_t *)prnt;
574
    char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
575
    unsigned i, j;
576
    unsigned bps;       /* bytes per sector */
577
    unsigned dps;       /* dentries per sector */
578
    unsigned blocks;
579
    fat_dentry_t *d;
580
    block_t *b;
581
 
582
    futex_down(&parentp->idx->lock);
583
    bs = block_bb_get(parentp->idx->dev_handle);
584
    bps = uint16_t_le2host(bs->bps);
585
    dps = bps / sizeof(fat_dentry_t);
586
    blocks = parentp->size / bps;
587
    for (i = 0; i < blocks; i++) {
588
        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
589
        for (j = 0; j < dps; j++) {
590
            d = ((fat_dentry_t *)b->data) + j;
591
            switch (fat_classify_dentry(d)) {
592
            case FAT_DENTRY_SKIP:
593
            case FAT_DENTRY_FREE:
594
                continue;
595
            case FAT_DENTRY_LAST:
596
                block_put(b);
597
                futex_up(&parentp->idx->lock);
598
                return NULL;
599
            default:
600
            case FAT_DENTRY_VALID:
601
                fat_dentry_name_get(d, name);
602
                break;
603
            }
604
            if (fat_dentry_namecmp(name, component) == 0) {
605
                /* hit */
606
                void *node;
607
                /*
608
                 * Assume tree hierarchy for locking.  We
609
                 * already have the parent and now we are going
610
                 * to lock the child.  Never lock in the oposite
611
                 * order.
612
                 */
613
                fat_idx_t *idx = fat_idx_get_by_pos(
614
                    parentp->idx->dev_handle, parentp->firstc,
615
                    i * dps + j);
616
                futex_up(&parentp->idx->lock);
617
                if (!idx) {
618
                    /*
619
                     * Can happen if memory is low or if we
620
                     * run out of 32-bit indices.
621
                     */
622
                    block_put(b);
623
                    return NULL;
624
                }
625
                node = fat_node_get_core(idx);
626
                futex_up(&idx->lock);
627
                block_put(b);
628
                return node;
629
            }
630
        }
631
        block_put(b);
632
    }
633
 
634
    futex_up(&parentp->idx->lock);
635
    return NULL;
636
}
637
 
638
fs_index_t fat_index_get(void *node)
639
{
640
    fat_node_t *fnodep = (fat_node_t *)node;
641
    if (!fnodep)
642
        return 0;
643
    return fnodep->idx->index;
644
}
645
 
646
size_t fat_size_get(void *node)
647
{
648
    return ((fat_node_t *)node)->size;
649
}
650
 
651
unsigned fat_lnkcnt_get(void *node)
652
{
653
    return ((fat_node_t *)node)->lnkcnt;
654
}
655
 
656
bool fat_has_children(void *node)
657
{
658
    fat_bs_t *bs;
659
    fat_node_t *nodep = (fat_node_t *)node;
660
    unsigned bps;
661
    unsigned dps;
662
    unsigned blocks;
663
    block_t *b;
664
    unsigned i, j;
665
 
666
    if (nodep->type != FAT_DIRECTORY)
667
        return false;
668
 
669
    futex_down(&nodep->idx->lock);
670
    bs = block_bb_get(nodep->idx->dev_handle);
671
    bps = uint16_t_le2host(bs->bps);
672
    dps = bps / sizeof(fat_dentry_t);
673
 
674
    blocks = nodep->size / bps;
675
 
676
    for (i = 0; i < blocks; i++) {
677
        fat_dentry_t *d;
678
 
679
        b = fat_block_get(bs, nodep, i, BLOCK_FLAGS_NONE);
680
        for (j = 0; j < dps; j++) {
681
            d = ((fat_dentry_t *)b->data) + j;
682
            switch (fat_classify_dentry(d)) {
683
            case FAT_DENTRY_SKIP:
684
            case FAT_DENTRY_FREE:
685
                continue;
686
            case FAT_DENTRY_LAST:
687
                block_put(b);
688
                futex_up(&nodep->idx->lock);
689
                return false;
690
            default:
691
            case FAT_DENTRY_VALID:
692
                block_put(b);
693
                futex_up(&nodep->idx->lock);
694
                return true;
695
            }
696
            block_put(b);
697
            futex_up(&nodep->idx->lock);
698
            return true;
699
        }
700
        block_put(b);
701
    }
702
 
703
    futex_up(&nodep->idx->lock);
704
    return false;
705
}
706
 
707
void *fat_root_get(dev_handle_t dev_handle)
708
{
709
    return fat_node_get(dev_handle, 0);
710
}
711
 
712
char fat_plb_get_char(unsigned pos)
713
{
714
    return fat_reg.plb_ro[pos % PLB_SIZE];
715
}
716
 
717
bool fat_is_directory(void *node)
718
{
719
    return ((fat_node_t *)node)->type == FAT_DIRECTORY;
720
}
721
 
722
bool fat_is_file(void *node)
723
{
724
    return ((fat_node_t *)node)->type == FAT_FILE;
725
}
726
 
727
/** libfs operations */
728
libfs_ops_t fat_libfs_ops = {
729
    .match = fat_match,
730
    .node_get = fat_node_get,
731
    .node_put = fat_node_put,
732
    .create = fat_create_node,
733
    .destroy = fat_destroy_node,
734
    .link = fat_link,
735
    .unlink = fat_unlink,
736
    .index_get = fat_index_get,
737
    .size_get = fat_size_get,
738
    .lnkcnt_get = fat_lnkcnt_get,
739
    .has_children = fat_has_children,
740
    .root_get = fat_root_get,
741
    .plb_get_char = fat_plb_get_char,
742
    .is_directory = fat_is_directory,
743
    .is_file = fat_is_file
744
};
745
 
746
/*
747
 * VFS operations.
748
 */
749
 
750
void fat_mounted(ipc_callid_t rid, ipc_call_t *request)
751
{
752
    dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
753
    fat_bs_t *bs;
754
    uint16_t bps;
755
    uint16_t rde;
756
    int rc;
757
 
758
    /* initialize libblock */
759
    rc = block_init(dev_handle, BS_SIZE);
760
    if (rc != EOK) {
761
        ipc_answer_0(rid, rc);
762
        return;
763
    }
764
 
765
    /* prepare the boot block */
766
    rc = block_bb_read(dev_handle, BS_BLOCK * BS_SIZE, BS_SIZE);
767
    if (rc != EOK) {
768
        block_fini(dev_handle);
769
        ipc_answer_0(rid, rc);
770
        return;
771
    }
772
 
773
    /* get the buffer with the boot sector */
774
    bs = block_bb_get(dev_handle);
775
 
776
    /* Read the number of root directory entries. */
777
    bps = uint16_t_le2host(bs->bps);
778
    rde = uint16_t_le2host(bs->root_ent_max);
779
 
780
    if (bps != BS_SIZE) {
781
        block_fini(dev_handle);
782
        ipc_answer_0(rid, ENOTSUP);
783
        return;
784
    }
785
 
786
    /* Initialize the block cache */
787
    rc = block_cache_init(dev_handle, bps, 0 /* XXX */);
788
    if (rc != EOK) {
789
        block_fini(dev_handle);
790
        ipc_answer_0(rid, rc);
791
        return;
792
    }
793
 
794
    rc = fat_idx_init_by_dev_handle(dev_handle);
795
    if (rc != EOK) {
796
        block_fini(dev_handle);
797
        ipc_answer_0(rid, rc);
798
        return;
799
    }
800
 
801
    /* Initialize the root node. */
802
    fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t));
803
    if (!rootp) {
804
        block_fini(dev_handle);
805
        fat_idx_fini_by_dev_handle(dev_handle);
806
        ipc_answer_0(rid, ENOMEM);
807
        return;
808
    }
809
    fat_node_initialize(rootp);
810
 
811
    fat_idx_t *ridxp = fat_idx_get_by_pos(dev_handle, FAT_CLST_ROOTPAR, 0);
812
    if (!ridxp) {
813
        block_fini(dev_handle);
814
        free(rootp);
815
        fat_idx_fini_by_dev_handle(dev_handle);
816
        ipc_answer_0(rid, ENOMEM);
817
        return;
818
    }
819
    assert(ridxp->index == 0);
820
    /* ridxp->lock held */
821
 
822
    rootp->type = FAT_DIRECTORY;
823
    rootp->firstc = FAT_CLST_ROOT;
824
    rootp->refcnt = 1;
825
    rootp->lnkcnt = 0;  /* FS root is not linked */
826
    rootp->size = rde * sizeof(fat_dentry_t);
827
    rootp->idx = ridxp;
828
    ridxp->nodep = rootp;
829
 
830
    futex_up(&ridxp->lock);
831
 
832
    ipc_answer_3(rid, EOK, ridxp->index, rootp->size, rootp->lnkcnt);
833
}
834
 
835
void fat_mount(ipc_callid_t rid, ipc_call_t *request)
836
{
837
    ipc_answer_0(rid, ENOTSUP);
838
}
839
 
840
void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
841
{
842
    libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
843
}
844
 
845
void fat_read(ipc_callid_t rid, ipc_call_t *request)
846
{
847
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
848
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
849
    off_t pos = (off_t)IPC_GET_ARG3(*request);
850
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
851
    fat_bs_t *bs;
852
    uint16_t bps;
853
    size_t bytes;
854
    block_t *b;
855
 
856
    if (!nodep) {
857
        ipc_answer_0(rid, ENOENT);
858
        return;
859
    }
860
 
861
    ipc_callid_t callid;
862
    size_t len;
863
    if (!ipc_data_read_receive(&callid, &len)) {
864
        fat_node_put(nodep);
865
        ipc_answer_0(callid, EINVAL);
866
        ipc_answer_0(rid, EINVAL);
867
        return;
868
    }
869
 
870
    bs = block_bb_get(dev_handle);
871
    bps = uint16_t_le2host(bs->bps);
872
 
873
    if (nodep->type == FAT_FILE) {
874
        /*
875
         * Our strategy for regular file reads is to read one block at
876
         * most and make use of the possibility to return less data than
877
         * requested. This keeps the code very simple.
878
         */
879
        if (pos >= nodep->size) {
880
            /* reading beyond the EOF */
881
            bytes = 0;
882
            (void) ipc_data_read_finalize(callid, NULL, 0);
883
        } else {
884
            bytes = min(len, bps - pos % bps);
885
            bytes = min(bytes, nodep->size - pos);
886
            b = fat_block_get(bs, nodep, pos / bps,
887
                BLOCK_FLAGS_NONE);
888
            (void) ipc_data_read_finalize(callid, b->data + pos % bps,
889
                bytes);
890
            block_put(b);
891
        }
892
    } else {
893
        unsigned bnum;
894
        off_t spos = pos;
895
        char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
896
        fat_dentry_t *d;
897
 
898
        assert(nodep->type == FAT_DIRECTORY);
899
        assert(nodep->size % bps == 0);
900
        assert(bps % sizeof(fat_dentry_t) == 0);
901
 
902
        /*
903
         * Our strategy for readdir() is to use the position pointer as
904
         * an index into the array of all dentries. On entry, it points
905
         * to the first unread dentry. If we skip any dentries, we bump
906
         * the position pointer accordingly.
907
         */
908
        bnum = (pos * sizeof(fat_dentry_t)) / bps;
909
        while (bnum < nodep->size / bps) {
910
            off_t o;
911
 
912
            b = fat_block_get(bs, nodep, bnum, BLOCK_FLAGS_NONE);
913
            for (o = pos % (bps / sizeof(fat_dentry_t));
914
                o < bps / sizeof(fat_dentry_t);
915
                o++, pos++) {
916
                d = ((fat_dentry_t *)b->data) + o;
917
                switch (fat_classify_dentry(d)) {
918
                case FAT_DENTRY_SKIP:
919
                case FAT_DENTRY_FREE:
920
                    continue;
921
                case FAT_DENTRY_LAST:
922
                    block_put(b);
923
                    goto miss;
924
                default:
925
                case FAT_DENTRY_VALID:
926
                    fat_dentry_name_get(d, name);
927
                    block_put(b);
928
                    goto hit;
929
                }
930
            }
931
            block_put(b);
932
            bnum++;
933
        }
934
miss:
935
        fat_node_put(nodep);
936
        ipc_answer_0(callid, ENOENT);
937
        ipc_answer_1(rid, ENOENT, 0);
938
        return;
939
hit:
940
        (void) ipc_data_read_finalize(callid, name, str_size(name) + 1);
941
        bytes = (pos - spos) + 1;
942
    }
943
 
944
    fat_node_put(nodep);
945
    ipc_answer_1(rid, EOK, (ipcarg_t)bytes);
946
}
947
 
948
void fat_write(ipc_callid_t rid, ipc_call_t *request)
949
{
950
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
951
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
952
    off_t pos = (off_t)IPC_GET_ARG3(*request);
953
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
954
    fat_bs_t *bs;
955
    size_t bytes;
956
    block_t *b;
957
    uint16_t bps;
958
    unsigned spc;
959
    unsigned bpc;       /* bytes per cluster */
960
    off_t boundary;
961
    int flags = BLOCK_FLAGS_NONE;
962
 
963
    if (!nodep) {
964
        ipc_answer_0(rid, ENOENT);
965
        return;
966
    }
967
 
968
    ipc_callid_t callid;
969
    size_t len;
970
    if (!ipc_data_write_receive(&callid, &len)) {
971
        fat_node_put(nodep);
972
        ipc_answer_0(callid, EINVAL);
973
        ipc_answer_0(rid, EINVAL);
974
        return;
975
    }
976
 
977
    bs = block_bb_get(dev_handle);
978
    bps = uint16_t_le2host(bs->bps);
979
    spc = bs->spc;
980
    bpc = bps * spc;
981
 
982
    /*
983
     * In all scenarios, we will attempt to write out only one block worth
984
     * of data at maximum. There might be some more efficient approaches,
985
     * but this one greatly simplifies fat_write(). Note that we can afford
986
     * to do this because the client must be ready to handle the return
987
     * value signalizing a smaller number of bytes written.
988
     */
989
    bytes = min(len, bps - pos % bps);
990
    if (bytes == bps)
991
        flags |= BLOCK_FLAGS_NOREAD;
992
 
993
    boundary = ROUND_UP(nodep->size, bpc);
994
    if (pos < boundary) {
995
        /*
996
         * This is the easier case - we are either overwriting already
997
         * existing contents or writing behind the EOF, but still within
998
         * the limits of the last cluster. The node size may grow to the
999
         * next block size boundary.
1000
         */
1001
        fat_fill_gap(bs, nodep, FAT_CLST_RES0, pos);
1002
        b = fat_block_get(bs, nodep, pos / bps, flags);
1003
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
1004
            bytes);
1005
        b->dirty = true;        /* need to sync block */
1006
        block_put(b);
1007
        if (pos + bytes > nodep->size) {
1008
            nodep->size = pos + bytes;
1009
            nodep->dirty = true;    /* need to sync node */
1010
        }
1011
        ipc_answer_2(rid, EOK, bytes, nodep->size);
1012
        fat_node_put(nodep);
1013
        return;
1014
    } else {
1015
        /*
1016
         * This is the more difficult case. We must allocate new
1017
         * clusters for the node and zero them out.
1018
         */
1019
        int status;
1020
        unsigned nclsts;
1021
        fat_cluster_t mcl, lcl;
1022
 
1023
        nclsts = (ROUND_UP(pos + bytes, bpc) - boundary) / bpc;
1024
        /* create an independent chain of nclsts clusters in all FATs */
1025
        status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl, &lcl);
1026
        if (status != EOK) {
1027
            /* could not allocate a chain of nclsts clusters */
1028
            fat_node_put(nodep);
1029
            ipc_answer_0(callid, status);
1030
            ipc_answer_0(rid, status);
1031
            return;
1032
        }
1033
        /* zero fill any gaps */
1034
        fat_fill_gap(bs, nodep, mcl, pos);
1035
        b = _fat_block_get(bs, dev_handle, lcl, (pos / bps) % spc,
1036
            flags);
1037
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
1038
            bytes);
1039
        b->dirty = true;        /* need to sync block */
1040
        block_put(b);
1041
        /*
1042
         * Append the cluster chain starting in mcl to the end of the
1043
         * node's cluster chain.
1044
         */
1045
        fat_append_clusters(bs, nodep, mcl);
1046
        nodep->size = pos + bytes;
1047
        nodep->dirty = true;        /* need to sync node */
1048
        ipc_answer_2(rid, EOK, bytes, nodep->size);
1049
        fat_node_put(nodep);
1050
        return;
1051
    }
1052
}
1053
 
1054
void fat_truncate(ipc_callid_t rid, ipc_call_t *request)
1055
{
1056
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
1057
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
1058
    size_t size = (off_t)IPC_GET_ARG3(*request);
1059
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
1060
    fat_bs_t *bs;
1061
    uint16_t bps;
1062
    uint8_t spc;
1063
    unsigned bpc;   /* bytes per cluster */
1064
    int rc;
1065
 
1066
    if (!nodep) {
1067
        ipc_answer_0(rid, ENOENT);
1068
        return;
1069
    }
1070
 
1071
    bs = block_bb_get(dev_handle);
1072
    bps = uint16_t_le2host(bs->bps);
1073
    spc = bs->spc;
1074
    bpc = bps * spc;
1075
 
1076
    if (nodep->size == size) {
1077
        rc = EOK;
1078
    } else if (nodep->size < size) {
1079
        /*
1080
         * The standard says we have the freedom to grow the node.
1081
         * For now, we simply return an error.
1082
         */
1083
        rc = EINVAL;
1084
    } else if (ROUND_UP(nodep->size, bpc) == ROUND_UP(size, bpc)) {
1085
        /*
1086
         * The node will be shrunk, but no clusters will be deallocated.
1087
         */
1088
        nodep->size = size;
1089
        nodep->dirty = true;        /* need to sync node */
1090
        rc = EOK;  
1091
    } else {
1092
        /*
1093
         * The node will be shrunk, clusters will be deallocated.
1094
         */
1095
        if (size == 0) {
1096
            fat_chop_clusters(bs, nodep, FAT_CLST_RES0);
1097
        } else {
1098
            fat_cluster_t lastc;
1099
            (void) fat_cluster_walk(bs, dev_handle, nodep->firstc,
1100
                &lastc, (size - 1) / bpc);
1101
            fat_chop_clusters(bs, nodep, lastc);
1102
        }
1103
        nodep->size = size;
1104
        nodep->dirty = true;        /* need to sync node */
1105
        rc = EOK;  
1106
    }
1107
    fat_node_put(nodep);
1108
    ipc_answer_0(rid, rc);
1109
    return;
1110
}
1111
 
1112
void fat_destroy(ipc_callid_t rid, ipc_call_t *request)
1113
{
1114
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
1115
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
1116
    int rc;
1117
 
1118
    fat_node_t *nodep = fat_node_get(dev_handle, index);
1119
    if (!nodep) {
1120
        ipc_answer_0(rid, ENOENT);
1121
        return;
1122
    }
1123
 
1124
    rc = fat_destroy_node(nodep);
1125
    ipc_answer_0(rid, rc);
1126
}
1127
 
1128
/**
1129
 * @}
1130
 */