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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>
4537 trochtova 51
#include <adt/hash_table.h>
52
#include <adt/list.h>
4419 trochtova 53
#include <assert.h>
54
#include <futex.h>
55
#include <sys/mman.h>
56
#include <align.h>
57
 
4420 trochtova 58
#define FAT_NODE(node)  ((node) ? (fat_node_t *) (node)->data : NULL)
59
#define FS_NODE(node)   ((node) ? (node)->bp : NULL)
60
 
4419 trochtova 61
/** Futex protecting the list of cached free FAT nodes. */
62
static futex_t ffn_futex = FUTEX_INITIALIZER;
63
 
64
/** List of cached free FAT nodes. */
65
static LIST_INITIALIZE(ffn_head);
66
 
67
static void fat_node_initialize(fat_node_t *node)
68
{
69
    futex_initialize(&node->lock, 1);
4420 trochtova 70
    node->bp = NULL;
4419 trochtova 71
    node->idx = NULL;
72
    node->type = 0;
73
    link_initialize(&node->ffn_link);
74
    node->size = 0;
75
    node->lnkcnt = 0;
76
    node->refcnt = 0;
77
    node->dirty = false;
78
}
79
 
80
static void fat_node_sync(fat_node_t *node)
81
{
82
    block_t *b;
83
    fat_bs_t *bs;
84
    fat_dentry_t *d;
85
    uint16_t bps;
86
    unsigned dps;
87
 
88
    assert(node->dirty);
89
 
90
    bs = block_bb_get(node->idx->dev_handle);
91
    bps = uint16_t_le2host(bs->bps);
92
    dps = bps / sizeof(fat_dentry_t);
93
 
94
    /* Read the block that contains the dentry of interest. */
95
    b = _fat_block_get(bs, node->idx->dev_handle, node->idx->pfc,
96
        (node->idx->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
97
 
98
    d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps);
99
 
100
    d->firstc = host2uint16_t_le(node->firstc);
101
    if (node->type == FAT_FILE) {
102
        d->size = host2uint32_t_le(node->size);
103
    } else if (node->type == FAT_DIRECTORY) {
104
        d->attr = FAT_ATTR_SUBDIR;
105
    }
106
 
107
    /* TODO: update other fields? (e.g time fields) */
108
 
109
    b->dirty = true;        /* need to sync block */
110
    block_put(b);
111
}
112
 
113
static fat_node_t *fat_node_get_new(void)
114
{
4420 trochtova 115
    fs_node_t *fn;
4419 trochtova 116
    fat_node_t *nodep;
117
 
118
    futex_down(&ffn_futex);
119
    if (!list_empty(&ffn_head)) {
120
        /* Try to use a cached free node structure. */
121
        fat_idx_t *idxp_tmp;
122
        nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
123
        if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
124
            goto skip_cache;
125
        idxp_tmp = nodep->idx;
126
        if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
127
            futex_up(&nodep->lock);
128
            goto skip_cache;
129
        }
130
        list_remove(&nodep->ffn_link);
131
        futex_up(&ffn_futex);
132
        if (nodep->dirty)
133
            fat_node_sync(nodep);
134
        idxp_tmp->nodep = NULL;
135
        futex_up(&nodep->lock);
136
        futex_up(&idxp_tmp->lock);
4420 trochtova 137
        fn = FS_NODE(nodep);
4419 trochtova 138
    } else {
139
skip_cache:
140
        /* Try to allocate a new node structure. */
141
        futex_up(&ffn_futex);
4420 trochtova 142
        fn = (fs_node_t *)malloc(sizeof(fs_node_t));
143
        if (!fn)
144
            return NULL;
4419 trochtova 145
        nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
4420 trochtova 146
        if (!nodep) {
147
            free(fn);
4419 trochtova 148
            return NULL;
4420 trochtova 149
        }
4419 trochtova 150
    }
151
    fat_node_initialize(nodep);
4420 trochtova 152
    fs_node_initialize(fn);
153
    fn->data = nodep;
154
    nodep->bp = fn;
4419 trochtova 155
 
156
    return nodep;
157
}
158
 
159
/** Internal version of fat_node_get().
160
 *
161
 * @param idxp      Locked index structure.
162
 */
4420 trochtova 163
static fat_node_t *fat_node_get_core(fat_idx_t *idxp)
4419 trochtova 164
{
165
    block_t *b;
166
    fat_bs_t *bs;
167
    fat_dentry_t *d;
168
    fat_node_t *nodep = NULL;
169
    unsigned bps;
170
    unsigned spc;
171
    unsigned dps;
172
 
173
    if (idxp->nodep) {
174
        /*
175
         * We are lucky.
176
         * The node is already instantiated in memory.
177
         */
178
        futex_down(&idxp->nodep->lock);
179
        if (!idxp->nodep->refcnt++)
180
            list_remove(&idxp->nodep->ffn_link);
181
        futex_up(&idxp->nodep->lock);
182
        return idxp->nodep;
183
    }
184
 
185
    /*
186
     * We must instantiate the node from the file system.
187
     */
188
 
189
    assert(idxp->pfc);
190
 
191
    nodep = fat_node_get_new();
192
    if (!nodep)
193
        return NULL;
194
 
195
    bs = block_bb_get(idxp->dev_handle);
196
    bps = uint16_t_le2host(bs->bps);
197
    spc = bs->spc;
198
    dps = bps / sizeof(fat_dentry_t);
199
 
200
    /* Read the block that contains the dentry of interest. */
201
    b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc,
202
        (idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
203
    assert(b);
204
 
205
    d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
206
    if (d->attr & FAT_ATTR_SUBDIR) {
207
        /*
208
         * The only directory which does not have this bit set is the
209
         * root directory itself. The root directory node is handled
210
         * and initialized elsewhere.
211
         */
212
        nodep->type = FAT_DIRECTORY;
213
        /*
214
         * Unfortunately, the 'size' field of the FAT dentry is not
215
         * defined for the directory entry type. We must determine the
216
         * size of the directory by walking the FAT.
217
         */
218
        nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle,
219
            uint16_t_le2host(d->firstc));
220
    } else {
221
        nodep->type = FAT_FILE;
222
        nodep->size = uint32_t_le2host(d->size);
223
    }
224
    nodep->firstc = uint16_t_le2host(d->firstc);
225
    nodep->lnkcnt = 1;
226
    nodep->refcnt = 1;
227
 
228
    block_put(b);
229
 
230
    /* Link the idx structure with the node structure. */
231
    nodep->idx = idxp;
232
    idxp->nodep = nodep;
233
 
234
    return nodep;
235
}
236
 
237
/*
238
 * Forward declarations of FAT libfs operations.
239
 */
4420 trochtova 240
static fs_node_t *fat_node_get(dev_handle_t, fs_index_t);
241
static void fat_node_put(fs_node_t *);
242
static fs_node_t *fat_create_node(dev_handle_t, int);
243
static int fat_destroy_node(fs_node_t *);
244
static int fat_link(fs_node_t *, fs_node_t *, const char *);
245
static int fat_unlink(fs_node_t *, fs_node_t *, const char *);
246
static fs_node_t *fat_match(fs_node_t *, const char *);
247
static fs_index_t fat_index_get(fs_node_t *);
248
static size_t fat_size_get(fs_node_t *);
249
static unsigned fat_lnkcnt_get(fs_node_t *);
250
static bool fat_has_children(fs_node_t *);
251
static fs_node_t *fat_root_get(dev_handle_t);
4419 trochtova 252
static char fat_plb_get_char(unsigned);
4420 trochtova 253
static bool fat_is_directory(fs_node_t *);
254
static bool fat_is_file(fs_node_t *node);
4419 trochtova 255
 
256
/*
257
 * FAT libfs operations.
258
 */
259
 
260
/** Instantiate a FAT in-core node. */
4420 trochtova 261
fs_node_t *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
4419 trochtova 262
{
4420 trochtova 263
    fat_node_t *nodep;
4419 trochtova 264
    fat_idx_t *idxp;
265
 
266
    idxp = fat_idx_get_by_index(dev_handle, index);
267
    if (!idxp)
268
        return NULL;
269
    /* idxp->lock held */
4420 trochtova 270
    nodep = fat_node_get_core(idxp);
4419 trochtova 271
    futex_up(&idxp->lock);
4420 trochtova 272
    return FS_NODE(nodep);
4419 trochtova 273
}
274
 
4420 trochtova 275
void fat_node_put(fs_node_t *fn)
4419 trochtova 276
{
4420 trochtova 277
    fat_node_t *nodep = FAT_NODE(fn);
4419 trochtova 278
    bool destroy = false;
279
 
280
    futex_down(&nodep->lock);
281
    if (!--nodep->refcnt) {
282
        if (nodep->idx) {
283
            futex_down(&ffn_futex);
284
            list_append(&nodep->ffn_link, &ffn_head);
285
            futex_up(&ffn_futex);
286
        } else {
287
            /*
288
             * The node does not have any index structure associated
289
             * with itself. This can only mean that we are releasing
290
             * the node after a failed attempt to allocate the index
291
             * structure for it.
292
             */
293
            destroy = true;
294
        }
295
    }
296
    futex_up(&nodep->lock);
4420 trochtova 297
    if (destroy) {
298
        free(nodep->bp);
299
        free(nodep);
300
    }
4419 trochtova 301
}
302
 
4420 trochtova 303
fs_node_t *fat_create_node(dev_handle_t dev_handle, int flags)
4419 trochtova 304
{
305
    fat_idx_t *idxp;
306
    fat_node_t *nodep;
307
    fat_bs_t *bs;
308
    fat_cluster_t mcl, lcl;
309
    uint16_t bps;
310
    int rc;
311
 
312
    bs = block_bb_get(dev_handle);
313
    bps = uint16_t_le2host(bs->bps);
314
    if (flags & L_DIRECTORY) {
315
        /* allocate a cluster */
316
        rc = fat_alloc_clusters(bs, dev_handle, 1, &mcl, &lcl);
317
        if (rc != EOK)
318
            return NULL;
319
    }
320
 
321
    nodep = fat_node_get_new();
322
    if (!nodep) {
323
        fat_free_clusters(bs, dev_handle, mcl);
324
        return NULL;
325
    }
326
    idxp = fat_idx_get_new(dev_handle);
327
    if (!idxp) {
328
        fat_free_clusters(bs, dev_handle, mcl);
4420 trochtova 329
        fat_node_put(FS_NODE(nodep));
4419 trochtova 330
        return NULL;
331
    }
332
    /* idxp->lock held */
333
    if (flags & L_DIRECTORY) {
334
        int i;
335
        block_t *b;
336
 
337
        /*
338
         * Populate the new cluster with unused dentries.
339
         */
340
        for (i = 0; i < bs->spc; i++) {
341
            b = _fat_block_get(bs, dev_handle, mcl, i,
342
                BLOCK_FLAGS_NOREAD);
343
            /* mark all dentries as never-used */
344
            memset(b->data, 0, bps);
345
            b->dirty = false;
346
            block_put(b);
347
        }
348
        nodep->type = FAT_DIRECTORY;
349
        nodep->firstc = mcl;
350
        nodep->size = bps * bs->spc;
351
    } else {
352
        nodep->type = FAT_FILE;
353
        nodep->firstc = FAT_CLST_RES0;
354
        nodep->size = 0;
355
    }
356
    nodep->lnkcnt = 0;  /* not linked anywhere */
357
    nodep->refcnt = 1;
358
    nodep->dirty = true;
359
 
360
    nodep->idx = idxp;
361
    idxp->nodep = nodep;
362
 
363
    futex_up(&idxp->lock);
4420 trochtova 364
    return FS_NODE(nodep);
4419 trochtova 365
}
366
 
4420 trochtova 367
int fat_destroy_node(fs_node_t *fn)
4419 trochtova 368
{
4420 trochtova 369
    fat_node_t *nodep = FAT_NODE(fn);
4419 trochtova 370
    fat_bs_t *bs;
371
 
372
    /*
373
     * The node is not reachable from the file system. This means that the
374
     * link count should be zero and that the index structure cannot be
375
     * found in the position hash. Obviously, we don't need to lock the node
376
     * nor its index structure.
377
     */
378
    assert(nodep->lnkcnt == 0);
379
 
380
    /*
381
     * The node may not have any children.
382
     */
4420 trochtova 383
    assert(fat_has_children(fn) == false);
4419 trochtova 384
 
385
    bs = block_bb_get(nodep->idx->dev_handle);
386
    if (nodep->firstc != FAT_CLST_RES0) {
387
        assert(nodep->size);
388
        /* Free all clusters allocated to the node. */
389
        fat_free_clusters(bs, nodep->idx->dev_handle, nodep->firstc);
390
    }
391
 
392
    fat_idx_destroy(nodep->idx);
4420 trochtova 393
    free(nodep->bp);
4419 trochtova 394
    free(nodep);
395
    return EOK;
396
}
397
 
4420 trochtova 398
int fat_link(fs_node_t *pfn, fs_node_t *cfn, const char *name)
4419 trochtova 399
{
4420 trochtova 400
    fat_node_t *parentp = FAT_NODE(pfn);
401
    fat_node_t *childp = FAT_NODE(cfn);
4419 trochtova 402
    fat_dentry_t *d;
403
    fat_bs_t *bs;
404
    block_t *b;
405
    int i, j;
406
    uint16_t bps;
407
    unsigned dps;
408
    unsigned blocks;
409
    fat_cluster_t mcl, lcl;
410
    int rc;
411
 
412
    futex_down(&childp->lock);
413
    if (childp->lnkcnt == 1) {
414
        /*
415
         * On FAT, we don't support multiple hard links.
416
         */
417
        futex_up(&childp->lock);
418
        return EMLINK;
419
    }
420
    assert(childp->lnkcnt == 0);
421
    futex_up(&childp->lock);
422
 
423
    if (!fat_dentry_name_verify(name)) {
424
        /*
425
         * Attempt to create unsupported name.
426
         */
427
        return ENOTSUP;
428
    }
429
 
430
    /*
431
     * Get us an unused parent node's dentry or grow the parent and allocate
432
     * a new one.
433
     */
434
 
435
    futex_down(&parentp->idx->lock);
436
    bs = block_bb_get(parentp->idx->dev_handle);
437
    bps = uint16_t_le2host(bs->bps);
438
    dps = bps / sizeof(fat_dentry_t);
439
 
440
    blocks = parentp->size / bps;
441
 
442
    for (i = 0; i < blocks; i++) {
443
        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
444
        for (j = 0; j < dps; j++) {
445
            d = ((fat_dentry_t *)b->data) + j;
446
            switch (fat_classify_dentry(d)) {
447
            case FAT_DENTRY_SKIP:
448
            case FAT_DENTRY_VALID:
449
                /* skipping used and meta entries */
450
                continue;
451
            case FAT_DENTRY_FREE:
452
            case FAT_DENTRY_LAST:
453
                /* found an empty slot */
454
                goto hit;
455
            }
456
        }
457
        block_put(b);
458
    }
459
    j = 0;
460
 
461
    /*
462
     * We need to grow the parent in order to create a new unused dentry.
463
     */
464
    if (parentp->idx->pfc == FAT_CLST_ROOT) {
465
        /* Can't grow the root directory. */
466
        futex_up(&parentp->idx->lock);
467
        return ENOSPC;
468
    }
469
    rc = fat_alloc_clusters(bs, parentp->idx->dev_handle, 1, &mcl, &lcl);
470
    if (rc != EOK) {
471
        futex_up(&parentp->idx->lock);
472
        return rc;
473
    }
474
    fat_append_clusters(bs, parentp, mcl);
475
    b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NOREAD);
476
    d = (fat_dentry_t *)b->data;
477
    /*
478
     * Clear all dentries in the block except for the first one (the first
479
     * dentry will be cleared in the next step).
480
     */
481
    memset(d + 1, 0, bps - sizeof(fat_dentry_t));
482
 
483
hit:
484
    /*
485
     * At this point we only establish the link between the parent and the
486
     * child.  The dentry, except of the name and the extension, will remain
487
     * uninitialized until the corresponding node is synced. Thus the valid
488
     * dentry data is kept in the child node structure.
489
     */
490
    memset(d, 0, sizeof(fat_dentry_t));
491
    fat_dentry_name_set(d, name);
492
    b->dirty = true;        /* need to sync block */
493
    block_put(b);
494
    futex_up(&parentp->idx->lock);
495
 
496
    futex_down(&childp->idx->lock);
497
 
498
    /*
499
     * If possible, create the Sub-directory Identifier Entry and the
500
     * Sub-directory Parent Pointer Entry (i.e. "." and ".."). These entries
501
     * are not mandatory according to Standard ECMA-107 and HelenOS VFS does
502
     * not use them anyway, so this is rather a sign of our good will.
503
     */
504
    b = fat_block_get(bs, childp, 0, BLOCK_FLAGS_NONE);
505
    d = (fat_dentry_t *)b->data;
506
    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
507
        str_cmp(d->name, FAT_NAME_DOT) == 0) {
508
        memset(d, 0, sizeof(fat_dentry_t));
509
        str_cpy(d->name, 8, FAT_NAME_DOT);
510
        str_cpy(d->ext, 3, FAT_EXT_PAD);
511
        d->attr = FAT_ATTR_SUBDIR;
512
        d->firstc = host2uint16_t_le(childp->firstc);
513
        /* TODO: initialize also the date/time members. */
514
    }
515
    d++;
516
    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
517
        str_cmp(d->name, FAT_NAME_DOT_DOT) == 0) {
518
        memset(d, 0, sizeof(fat_dentry_t));
519
        str_cpy(d->name, 8, FAT_NAME_DOT_DOT);
520
        str_cpy(d->ext, 3, FAT_EXT_PAD);
521
        d->attr = FAT_ATTR_SUBDIR;
522
        d->firstc = (parentp->firstc == FAT_CLST_ROOT) ?
523
            host2uint16_t_le(FAT_CLST_RES0) :
524
            host2uint16_t_le(parentp->firstc);
525
        /* TODO: initialize also the date/time members. */
526
    }
527
    b->dirty = true;        /* need to sync block */
528
    block_put(b);
529
 
530
    childp->idx->pfc = parentp->firstc;
531
    childp->idx->pdi = i * dps + j;
532
    futex_up(&childp->idx->lock);
533
 
534
    futex_down(&childp->lock);
535
    childp->lnkcnt = 1;
536
    childp->dirty = true;       /* need to sync node */
537
    futex_up(&childp->lock);
538
 
539
    /*
540
     * Hash in the index structure into the position hash.
541
     */
542
    fat_idx_hashin(childp->idx);
543
 
544
    return EOK;
545
}
546
 
4420 trochtova 547
int fat_unlink(fs_node_t *pfn, fs_node_t *cfn, const char *nm)
4419 trochtova 548
{
4420 trochtova 549
    fat_node_t *parentp = FAT_NODE(pfn);
550
    fat_node_t *childp = FAT_NODE(cfn);
4419 trochtova 551
    fat_bs_t *bs;
552
    fat_dentry_t *d;
553
    uint16_t bps;
554
    block_t *b;
555
 
4420 trochtova 556
    if (!parentp)
557
        return EBUSY;
558
 
559
    if (fat_has_children(cfn))
560
        return ENOTEMPTY;
561
 
4419 trochtova 562
    futex_down(&parentp->lock);
563
    futex_down(&childp->lock);
564
    assert(childp->lnkcnt == 1);
565
    futex_down(&childp->idx->lock);
566
    bs = block_bb_get(childp->idx->dev_handle);
567
    bps = uint16_t_le2host(bs->bps);
568
 
569
    b = _fat_block_get(bs, childp->idx->dev_handle, childp->idx->pfc,
570
        (childp->idx->pdi * sizeof(fat_dentry_t)) / bps,
571
        BLOCK_FLAGS_NONE);
572
    d = (fat_dentry_t *)b->data +
573
        (childp->idx->pdi % (bps / sizeof(fat_dentry_t)));
574
    /* mark the dentry as not-currently-used */
575
    d->name[0] = FAT_DENTRY_ERASED;
576
    b->dirty = true;        /* need to sync block */
577
    block_put(b);
578
 
579
    /* remove the index structure from the position hash */
580
    fat_idx_hashout(childp->idx);
581
    /* clear position information */
582
    childp->idx->pfc = FAT_CLST_RES0;
583
    childp->idx->pdi = 0;
584
    futex_up(&childp->idx->lock);
585
    childp->lnkcnt = 0;
586
    childp->dirty = true;
587
    futex_up(&childp->lock);
588
    futex_up(&parentp->lock);
589
 
590
    return EOK;
591
}
592
 
4420 trochtova 593
fs_node_t *fat_match(fs_node_t *pfn, const char *component)
4419 trochtova 594
{
595
    fat_bs_t *bs;
4420 trochtova 596
    fat_node_t *parentp = FAT_NODE(pfn);
4419 trochtova 597
    char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
598
    unsigned i, j;
599
    unsigned bps;       /* bytes per sector */
600
    unsigned dps;       /* dentries per sector */
601
    unsigned blocks;
602
    fat_dentry_t *d;
603
    block_t *b;
604
 
605
    futex_down(&parentp->idx->lock);
606
    bs = block_bb_get(parentp->idx->dev_handle);
607
    bps = uint16_t_le2host(bs->bps);
608
    dps = bps / sizeof(fat_dentry_t);
609
    blocks = parentp->size / bps;
610
    for (i = 0; i < blocks; i++) {
611
        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
612
        for (j = 0; j < dps; j++) {
613
            d = ((fat_dentry_t *)b->data) + j;
614
            switch (fat_classify_dentry(d)) {
615
            case FAT_DENTRY_SKIP:
616
            case FAT_DENTRY_FREE:
617
                continue;
618
            case FAT_DENTRY_LAST:
619
                block_put(b);
620
                futex_up(&parentp->idx->lock);
621
                return NULL;
622
            default:
623
            case FAT_DENTRY_VALID:
624
                fat_dentry_name_get(d, name);
625
                break;
626
            }
627
            if (fat_dentry_namecmp(name, component) == 0) {
628
                /* hit */
4420 trochtova 629
                fat_node_t *nodep;
4419 trochtova 630
                /*
631
                 * Assume tree hierarchy for locking.  We
632
                 * already have the parent and now we are going
633
                 * to lock the child.  Never lock in the oposite
634
                 * order.
635
                 */
636
                fat_idx_t *idx = fat_idx_get_by_pos(
637
                    parentp->idx->dev_handle, parentp->firstc,
638
                    i * dps + j);
639
                futex_up(&parentp->idx->lock);
640
                if (!idx) {
641
                    /*
642
                     * Can happen if memory is low or if we
643
                     * run out of 32-bit indices.
644
                     */
645
                    block_put(b);
646
                    return NULL;
647
                }
4420 trochtova 648
                nodep = fat_node_get_core(idx);
4419 trochtova 649
                futex_up(&idx->lock);
650
                block_put(b);
4420 trochtova 651
                return FS_NODE(nodep);
4419 trochtova 652
            }
653
        }
654
        block_put(b);
655
    }
656
 
657
    futex_up(&parentp->idx->lock);
658
    return NULL;
659
}
660
 
4420 trochtova 661
fs_index_t fat_index_get(fs_node_t *fn)
4419 trochtova 662
{
4420 trochtova 663
    return FAT_NODE(fn)->idx->index;
4419 trochtova 664
}
665
 
4420 trochtova 666
size_t fat_size_get(fs_node_t *fn)
4419 trochtova 667
{
4420 trochtova 668
    return FAT_NODE(fn)->size;
4419 trochtova 669
}
670
 
4420 trochtova 671
unsigned fat_lnkcnt_get(fs_node_t *fn)
4419 trochtova 672
{
4420 trochtova 673
    return FAT_NODE(fn)->lnkcnt;
4419 trochtova 674
}
675
 
4420 trochtova 676
bool fat_has_children(fs_node_t *fn)
4419 trochtova 677
{
678
    fat_bs_t *bs;
4420 trochtova 679
    fat_node_t *nodep = FAT_NODE(fn);
4419 trochtova 680
    unsigned bps;
681
    unsigned dps;
682
    unsigned blocks;
683
    block_t *b;
684
    unsigned i, j;
685
 
686
    if (nodep->type != FAT_DIRECTORY)
687
        return false;
688
 
689
    futex_down(&nodep->idx->lock);
690
    bs = block_bb_get(nodep->idx->dev_handle);
691
    bps = uint16_t_le2host(bs->bps);
692
    dps = bps / sizeof(fat_dentry_t);
693
 
694
    blocks = nodep->size / bps;
695
 
696
    for (i = 0; i < blocks; i++) {
697
        fat_dentry_t *d;
698
 
699
        b = fat_block_get(bs, nodep, i, BLOCK_FLAGS_NONE);
700
        for (j = 0; j < dps; j++) {
701
            d = ((fat_dentry_t *)b->data) + j;
702
            switch (fat_classify_dentry(d)) {
703
            case FAT_DENTRY_SKIP:
704
            case FAT_DENTRY_FREE:
705
                continue;
706
            case FAT_DENTRY_LAST:
707
                block_put(b);
708
                futex_up(&nodep->idx->lock);
709
                return false;
710
            default:
711
            case FAT_DENTRY_VALID:
712
                block_put(b);
713
                futex_up(&nodep->idx->lock);
714
                return true;
715
            }
716
            block_put(b);
717
            futex_up(&nodep->idx->lock);
718
            return true;
719
        }
720
        block_put(b);
721
    }
722
 
723
    futex_up(&nodep->idx->lock);
724
    return false;
725
}
726
 
4420 trochtova 727
fs_node_t *fat_root_get(dev_handle_t dev_handle)
4419 trochtova 728
{
729
    return fat_node_get(dev_handle, 0);
730
}
731
 
732
char fat_plb_get_char(unsigned pos)
733
{
734
    return fat_reg.plb_ro[pos % PLB_SIZE];
735
}
736
 
4420 trochtova 737
bool fat_is_directory(fs_node_t *fn)
4419 trochtova 738
{
4420 trochtova 739
    return FAT_NODE(fn)->type == FAT_DIRECTORY;
4419 trochtova 740
}
741
 
4420 trochtova 742
bool fat_is_file(fs_node_t *fn)
4419 trochtova 743
{
4420 trochtova 744
    return FAT_NODE(fn)->type == FAT_FILE;
4419 trochtova 745
}
746
 
747
/** libfs operations */
748
libfs_ops_t fat_libfs_ops = {
749
    .match = fat_match,
750
    .node_get = fat_node_get,
751
    .node_put = fat_node_put,
752
    .create = fat_create_node,
753
    .destroy = fat_destroy_node,
754
    .link = fat_link,
755
    .unlink = fat_unlink,
756
    .index_get = fat_index_get,
757
    .size_get = fat_size_get,
758
    .lnkcnt_get = fat_lnkcnt_get,
759
    .has_children = fat_has_children,
760
    .root_get = fat_root_get,
761
    .plb_get_char = fat_plb_get_char,
762
    .is_directory = fat_is_directory,
763
    .is_file = fat_is_file
764
};
765
 
766
/*
767
 * VFS operations.
768
 */
769
 
770
void fat_mounted(ipc_callid_t rid, ipc_call_t *request)
771
{
772
    dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
773
    fat_bs_t *bs;
774
    uint16_t bps;
775
    uint16_t rde;
776
    int rc;
777
 
4420 trochtova 778
    /* accept the mount options */
779
    ipc_callid_t callid;
780
    size_t size;
781
    if (!ipc_data_write_receive(&callid, &size)) {
782
        ipc_answer_0(callid, EINVAL);
783
        ipc_answer_0(rid, EINVAL);
784
        return;
785
    }
786
    char *opts = malloc(size + 1);
787
    if (!opts) {
788
        ipc_answer_0(callid, ENOMEM);
789
        ipc_answer_0(rid, ENOMEM);
790
        return;
791
    }
792
    ipcarg_t retval = ipc_data_write_finalize(callid, opts, size);
793
    if (retval != EOK) {
794
        ipc_answer_0(rid, retval);
795
        free(opts);
796
        return;
797
    }
798
    opts[size] = '\0';
799
 
4419 trochtova 800
    /* initialize libblock */
801
    rc = block_init(dev_handle, BS_SIZE);
802
    if (rc != EOK) {
803
        ipc_answer_0(rid, rc);
804
        return;
805
    }
806
 
807
    /* prepare the boot block */
808
    rc = block_bb_read(dev_handle, BS_BLOCK * BS_SIZE, BS_SIZE);
809
    if (rc != EOK) {
810
        block_fini(dev_handle);
811
        ipc_answer_0(rid, rc);
812
        return;
813
    }
814
 
815
    /* get the buffer with the boot sector */
816
    bs = block_bb_get(dev_handle);
817
 
818
    /* Read the number of root directory entries. */
819
    bps = uint16_t_le2host(bs->bps);
820
    rde = uint16_t_le2host(bs->root_ent_max);
821
 
822
    if (bps != BS_SIZE) {
823
        block_fini(dev_handle);
824
        ipc_answer_0(rid, ENOTSUP);
825
        return;
826
    }
827
 
828
    /* Initialize the block cache */
829
    rc = block_cache_init(dev_handle, bps, 0 /* XXX */);
830
    if (rc != EOK) {
831
        block_fini(dev_handle);
832
        ipc_answer_0(rid, rc);
833
        return;
834
    }
835
 
836
    rc = fat_idx_init_by_dev_handle(dev_handle);
837
    if (rc != EOK) {
838
        block_fini(dev_handle);
839
        ipc_answer_0(rid, rc);
840
        return;
841
    }
842
 
843
    /* Initialize the root node. */
4420 trochtova 844
    fs_node_t *rfn = (fs_node_t *)malloc(sizeof(fs_node_t));
845
    if (!rfn) {
846
        block_fini(dev_handle);
847
        fat_idx_fini_by_dev_handle(dev_handle);
848
        ipc_answer_0(rid, ENOMEM);
849
        return;
850
    }
851
    fs_node_initialize(rfn);
4419 trochtova 852
    fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t));
853
    if (!rootp) {
4420 trochtova 854
        free(rfn);
4419 trochtova 855
        block_fini(dev_handle);
856
        fat_idx_fini_by_dev_handle(dev_handle);
857
        ipc_answer_0(rid, ENOMEM);
858
        return;
859
    }
860
    fat_node_initialize(rootp);
861
 
862
    fat_idx_t *ridxp = fat_idx_get_by_pos(dev_handle, FAT_CLST_ROOTPAR, 0);
863
    if (!ridxp) {
4420 trochtova 864
        free(rfn);
865
        free(rootp);
4419 trochtova 866
        block_fini(dev_handle);
867
        fat_idx_fini_by_dev_handle(dev_handle);
868
        ipc_answer_0(rid, ENOMEM);
869
        return;
870
    }
871
    assert(ridxp->index == 0);
872
    /* ridxp->lock held */
873
 
874
    rootp->type = FAT_DIRECTORY;
875
    rootp->firstc = FAT_CLST_ROOT;
876
    rootp->refcnt = 1;
877
    rootp->lnkcnt = 0;  /* FS root is not linked */
878
    rootp->size = rde * sizeof(fat_dentry_t);
879
    rootp->idx = ridxp;
880
    ridxp->nodep = rootp;
4420 trochtova 881
    rootp->bp = rfn;
882
    rfn->data = rootp;
4419 trochtova 883
 
884
    futex_up(&ridxp->lock);
885
 
886
    ipc_answer_3(rid, EOK, ridxp->index, rootp->size, rootp->lnkcnt);
887
}
888
 
889
void fat_mount(ipc_callid_t rid, ipc_call_t *request)
890
{
4439 trochtova 891
    libfs_mount(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
4419 trochtova 892
}
893
 
894
void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
895
{
896
    libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
897
}
898
 
899
void fat_read(ipc_callid_t rid, ipc_call_t *request)
900
{
901
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
902
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
903
    off_t pos = (off_t)IPC_GET_ARG3(*request);
4420 trochtova 904
    fs_node_t *fn = fat_node_get(dev_handle, index);
905
    fat_node_t *nodep;
4419 trochtova 906
    fat_bs_t *bs;
907
    uint16_t bps;
908
    size_t bytes;
909
    block_t *b;
910
 
4420 trochtova 911
    if (!fn) {
4419 trochtova 912
        ipc_answer_0(rid, ENOENT);
913
        return;
914
    }
4420 trochtova 915
    nodep = FAT_NODE(fn);
4419 trochtova 916
 
917
    ipc_callid_t callid;
918
    size_t len;
919
    if (!ipc_data_read_receive(&callid, &len)) {
4420 trochtova 920
        fat_node_put(fn);
4419 trochtova 921
        ipc_answer_0(callid, EINVAL);
922
        ipc_answer_0(rid, EINVAL);
923
        return;
924
    }
925
 
926
    bs = block_bb_get(dev_handle);
927
    bps = uint16_t_le2host(bs->bps);
928
 
929
    if (nodep->type == FAT_FILE) {
930
        /*
931
         * Our strategy for regular file reads is to read one block at
932
         * most and make use of the possibility to return less data than
933
         * requested. This keeps the code very simple.
934
         */
935
        if (pos >= nodep->size) {
936
            /* reading beyond the EOF */
937
            bytes = 0;
938
            (void) ipc_data_read_finalize(callid, NULL, 0);
939
        } else {
940
            bytes = min(len, bps - pos % bps);
941
            bytes = min(bytes, nodep->size - pos);
942
            b = fat_block_get(bs, nodep, pos / bps,
943
                BLOCK_FLAGS_NONE);
944
            (void) ipc_data_read_finalize(callid, b->data + pos % bps,
945
                bytes);
946
            block_put(b);
947
        }
948
    } else {
949
        unsigned bnum;
950
        off_t spos = pos;
951
        char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
952
        fat_dentry_t *d;
953
 
954
        assert(nodep->type == FAT_DIRECTORY);
955
        assert(nodep->size % bps == 0);
956
        assert(bps % sizeof(fat_dentry_t) == 0);
957
 
958
        /*
959
         * Our strategy for readdir() is to use the position pointer as
960
         * an index into the array of all dentries. On entry, it points
961
         * to the first unread dentry. If we skip any dentries, we bump
962
         * the position pointer accordingly.
963
         */
964
        bnum = (pos * sizeof(fat_dentry_t)) / bps;
965
        while (bnum < nodep->size / bps) {
966
            off_t o;
967
 
968
            b = fat_block_get(bs, nodep, bnum, BLOCK_FLAGS_NONE);
969
            for (o = pos % (bps / sizeof(fat_dentry_t));
970
                o < bps / sizeof(fat_dentry_t);
971
                o++, pos++) {
972
                d = ((fat_dentry_t *)b->data) + o;
973
                switch (fat_classify_dentry(d)) {
974
                case FAT_DENTRY_SKIP:
975
                case FAT_DENTRY_FREE:
976
                    continue;
977
                case FAT_DENTRY_LAST:
978
                    block_put(b);
979
                    goto miss;
980
                default:
981
                case FAT_DENTRY_VALID:
982
                    fat_dentry_name_get(d, name);
983
                    block_put(b);
984
                    goto hit;
985
                }
986
            }
987
            block_put(b);
988
            bnum++;
989
        }
990
miss:
4420 trochtova 991
        fat_node_put(fn);
4419 trochtova 992
        ipc_answer_0(callid, ENOENT);
993
        ipc_answer_1(rid, ENOENT, 0);
994
        return;
995
hit:
996
        (void) ipc_data_read_finalize(callid, name, str_size(name) + 1);
997
        bytes = (pos - spos) + 1;
998
    }
999
 
4420 trochtova 1000
    fat_node_put(fn);
4419 trochtova 1001
    ipc_answer_1(rid, EOK, (ipcarg_t)bytes);
1002
}
1003
 
1004
void fat_write(ipc_callid_t rid, ipc_call_t *request)
1005
{
1006
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
1007
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
1008
    off_t pos = (off_t)IPC_GET_ARG3(*request);
4420 trochtova 1009
    fs_node_t *fn = fat_node_get(dev_handle, index);
1010
    fat_node_t *nodep;
4419 trochtova 1011
    fat_bs_t *bs;
1012
    size_t bytes;
1013
    block_t *b;
1014
    uint16_t bps;
1015
    unsigned spc;
1016
    unsigned bpc;       /* bytes per cluster */
1017
    off_t boundary;
1018
    int flags = BLOCK_FLAGS_NONE;
1019
 
4420 trochtova 1020
    if (!fn) {
4419 trochtova 1021
        ipc_answer_0(rid, ENOENT);
1022
        return;
1023
    }
4420 trochtova 1024
    nodep = FAT_NODE(fn);
4419 trochtova 1025
 
1026
    ipc_callid_t callid;
1027
    size_t len;
1028
    if (!ipc_data_write_receive(&callid, &len)) {
4420 trochtova 1029
        fat_node_put(fn);
4419 trochtova 1030
        ipc_answer_0(callid, EINVAL);
1031
        ipc_answer_0(rid, EINVAL);
1032
        return;
1033
    }
1034
 
1035
    bs = block_bb_get(dev_handle);
1036
    bps = uint16_t_le2host(bs->bps);
1037
    spc = bs->spc;
1038
    bpc = bps * spc;
1039
 
1040
    /*
1041
     * In all scenarios, we will attempt to write out only one block worth
1042
     * of data at maximum. There might be some more efficient approaches,
1043
     * but this one greatly simplifies fat_write(). Note that we can afford
1044
     * to do this because the client must be ready to handle the return
1045
     * value signalizing a smaller number of bytes written.
1046
     */
1047
    bytes = min(len, bps - pos % bps);
1048
    if (bytes == bps)
1049
        flags |= BLOCK_FLAGS_NOREAD;
1050
 
1051
    boundary = ROUND_UP(nodep->size, bpc);
1052
    if (pos < boundary) {
1053
        /*
1054
         * This is the easier case - we are either overwriting already
1055
         * existing contents or writing behind the EOF, but still within
1056
         * the limits of the last cluster. The node size may grow to the
1057
         * next block size boundary.
1058
         */
1059
        fat_fill_gap(bs, nodep, FAT_CLST_RES0, pos);
1060
        b = fat_block_get(bs, nodep, pos / bps, flags);
1061
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
1062
            bytes);
1063
        b->dirty = true;        /* need to sync block */
1064
        block_put(b);
1065
        if (pos + bytes > nodep->size) {
1066
            nodep->size = pos + bytes;
1067
            nodep->dirty = true;    /* need to sync node */
1068
        }
1069
        ipc_answer_2(rid, EOK, bytes, nodep->size);
4420 trochtova 1070
        fat_node_put(fn);
4419 trochtova 1071
        return;
1072
    } else {
1073
        /*
1074
         * This is the more difficult case. We must allocate new
1075
         * clusters for the node and zero them out.
1076
         */
1077
        int status;
1078
        unsigned nclsts;
1079
        fat_cluster_t mcl, lcl;
1080
 
1081
        nclsts = (ROUND_UP(pos + bytes, bpc) - boundary) / bpc;
1082
        /* create an independent chain of nclsts clusters in all FATs */
1083
        status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl, &lcl);
1084
        if (status != EOK) {
1085
            /* could not allocate a chain of nclsts clusters */
4420 trochtova 1086
            fat_node_put(fn);
4419 trochtova 1087
            ipc_answer_0(callid, status);
1088
            ipc_answer_0(rid, status);
1089
            return;
1090
        }
1091
        /* zero fill any gaps */
1092
        fat_fill_gap(bs, nodep, mcl, pos);
1093
        b = _fat_block_get(bs, dev_handle, lcl, (pos / bps) % spc,
1094
            flags);
1095
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
1096
            bytes);
1097
        b->dirty = true;        /* need to sync block */
1098
        block_put(b);
1099
        /*
1100
         * Append the cluster chain starting in mcl to the end of the
1101
         * node's cluster chain.
1102
         */
1103
        fat_append_clusters(bs, nodep, mcl);
1104
        nodep->size = pos + bytes;
1105
        nodep->dirty = true;        /* need to sync node */
1106
        ipc_answer_2(rid, EOK, bytes, nodep->size);
4420 trochtova 1107
        fat_node_put(fn);
4419 trochtova 1108
        return;
1109
    }
1110
}
1111
 
1112
void fat_truncate(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
    size_t size = (off_t)IPC_GET_ARG3(*request);
4420 trochtova 1117
    fs_node_t *fn = fat_node_get(dev_handle, index);
1118
    fat_node_t *nodep;
4419 trochtova 1119
    fat_bs_t *bs;
1120
    uint16_t bps;
1121
    uint8_t spc;
1122
    unsigned bpc;   /* bytes per cluster */
1123
    int rc;
1124
 
4420 trochtova 1125
    if (!fn) {
4419 trochtova 1126
        ipc_answer_0(rid, ENOENT);
1127
        return;
1128
    }
4420 trochtova 1129
    nodep = FAT_NODE(fn);
4419 trochtova 1130
 
1131
    bs = block_bb_get(dev_handle);
1132
    bps = uint16_t_le2host(bs->bps);
1133
    spc = bs->spc;
1134
    bpc = bps * spc;
1135
 
1136
    if (nodep->size == size) {
1137
        rc = EOK;
1138
    } else if (nodep->size < size) {
1139
        /*
1140
         * The standard says we have the freedom to grow the node.
1141
         * For now, we simply return an error.
1142
         */
1143
        rc = EINVAL;
1144
    } else if (ROUND_UP(nodep->size, bpc) == ROUND_UP(size, bpc)) {
1145
        /*
1146
         * The node will be shrunk, but no clusters will be deallocated.
1147
         */
1148
        nodep->size = size;
1149
        nodep->dirty = true;        /* need to sync node */
1150
        rc = EOK;  
1151
    } else {
1152
        /*
1153
         * The node will be shrunk, clusters will be deallocated.
1154
         */
1155
        if (size == 0) {
1156
            fat_chop_clusters(bs, nodep, FAT_CLST_RES0);
1157
        } else {
1158
            fat_cluster_t lastc;
1159
            (void) fat_cluster_walk(bs, dev_handle, nodep->firstc,
1160
                &lastc, (size - 1) / bpc);
1161
            fat_chop_clusters(bs, nodep, lastc);
1162
        }
1163
        nodep->size = size;
1164
        nodep->dirty = true;        /* need to sync node */
1165
        rc = EOK;  
1166
    }
4420 trochtova 1167
    fat_node_put(fn);
4419 trochtova 1168
    ipc_answer_0(rid, rc);
1169
    return;
1170
}
1171
 
4537 trochtova 1172
void fat_close(ipc_callid_t rid, ipc_call_t *request)
1173
{
1174
    ipc_answer_0(rid, EOK);
1175
}
1176
 
4419 trochtova 1177
void fat_destroy(ipc_callid_t rid, ipc_call_t *request)
1178
{
1179
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
1180
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
1181
    int rc;
1182
 
4420 trochtova 1183
    fs_node_t *fn = fat_node_get(dev_handle, index);
1184
    if (!fn) {
4419 trochtova 1185
        ipc_answer_0(rid, ENOENT);
1186
        return;
1187
    }
1188
 
4420 trochtova 1189
    rc = fat_destroy_node(fn);
4419 trochtova 1190
    ipc_answer_0(rid, rc);
1191
}
1192
 
4537 trochtova 1193
void fat_open_node(ipc_callid_t rid, ipc_call_t *request)
1194
{
1195
    libfs_open_node(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
1196
}
1197
 
1198
void fat_device(ipc_callid_t rid, ipc_call_t *request)
1199
{
1200
    ipc_answer_0(rid, ENOTSUP);
1201
}
1202
 
1203
void fat_sync(ipc_callid_t rid, ipc_call_t *request)
1204
{
1205
    /* Dummy implementation */
1206
    ipc_answer_0(rid, EOK);
1207
}
1208
 
4419 trochtova 1209
/**
1210
 * @}
4537 trochtova 1211
 */