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2627 jermar 1
/*
2793 jermar 2
 * Copyright (c) 2008 Jakub Jermar
2627 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"
4153 mejdrech 39
#include "fat_dentry.h"
40
#include "fat_fat.h"
2638 jermar 41
#include "../../vfs/vfs.h"
2793 jermar 42
#include <libfs.h>
4153 mejdrech 43
#include <libblock.h>
2627 jermar 44
#include <ipc/ipc.h>
3257 jermar 45
#include <ipc/services.h>
46
#include <ipc/devmap.h>
2627 jermar 47
#include <async.h>
48
#include <errno.h>
2793 jermar 49
#include <string.h>
2798 jermar 50
#include <byteorder.h>
2831 jermar 51
#include <libadt/hash_table.h>
52
#include <libadt/list.h>
53
#include <assert.h>
2856 jermar 54
#include <futex.h>
3257 jermar 55
#include <sys/mman.h>
4153 mejdrech 56
#include <align.h>
2627 jermar 57
 
2951 jermar 58
/** Futex protecting the list of cached free FAT nodes. */
59
static futex_t ffn_futex = FUTEX_INITIALIZER;
2843 jermar 60
 
2951 jermar 61
/** List of cached free FAT nodes. */
62
static LIST_INITIALIZE(ffn_head);
63
 
2831 jermar 64
static void fat_node_initialize(fat_node_t *node)
2793 jermar 65
{
2951 jermar 66
    futex_initialize(&node->lock, 1);
2864 jermar 67
    node->idx = NULL;
2831 jermar 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;
2793 jermar 74
}
75
 
4153 mejdrech 76
static void fat_node_sync(fat_node_t *node)
2843 jermar 77
{
4153 mejdrech 78
    block_t *b;
79
    fat_bs_t *bs;
80
    fat_dentry_t *d;
2843 jermar 81
    uint16_t bps;
4153 mejdrech 82
    unsigned dps;
2843 jermar 83
 
4153 mejdrech 84
    assert(node->dirty);
2843 jermar 85
 
4153 mejdrech 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);
2843 jermar 93
 
4153 mejdrech 94
    d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps);
2845 jermar 95
 
4153 mejdrech 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;
2845 jermar 101
    }
4153 mejdrech 102
 
103
    /* TODO: update other fields? (e.g time fields) */
104
 
105
    b->dirty = true;        /* need to sync block */
106
    block_put(b);
2845 jermar 107
}
108
 
4153 mejdrech 109
static fat_node_t *fat_node_get_new(void)
2831 jermar 110
{
4153 mejdrech 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;
2831 jermar 143
}
144
 
2951 jermar 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)
2831 jermar 150
{
2891 jermar 151
    block_t *b;
4153 mejdrech 152
    fat_bs_t *bs;
2891 jermar 153
    fat_dentry_t *d;
3312 jermar 154
    fat_node_t *nodep = NULL;
2891 jermar 155
    unsigned bps;
4153 mejdrech 156
    unsigned spc;
2891 jermar 157
    unsigned dps;
158
 
2951 jermar 159
    if (idxp->nodep) {
2891 jermar 160
        /*
161
         * We are lucky.
162
         * The node is already instantiated in memory.
163
         */
2951 jermar 164
        futex_down(&idxp->nodep->lock);
165
        if (!idxp->nodep->refcnt++)
3312 jermar 166
            list_remove(&idxp->nodep->ffn_link);
2951 jermar 167
        futex_up(&idxp->nodep->lock);
168
        return idxp->nodep;
2891 jermar 169
    }
170
 
171
    /*
172
     * We must instantiate the node from the file system.
173
     */
174
 
2951 jermar 175
    assert(idxp->pfc);
2891 jermar 176
 
4153 mejdrech 177
    nodep = fat_node_get_new();
178
    if (!nodep)
179
        return NULL;
2891 jermar 180
 
4153 mejdrech 181
    bs = block_bb_get(idxp->dev_handle);
182
    bps = uint16_t_le2host(bs->bps);
183
    spc = bs->spc;
2891 jermar 184
    dps = bps / sizeof(fat_dentry_t);
185
 
2893 jermar 186
    /* Read the block that contains the dentry of interest. */
4153 mejdrech 187
    b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc,
188
        (idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
2891 jermar 189
    assert(b);
190
 
2951 jermar 191
    d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
2893 jermar 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;
3282 jermar 199
        /*
3325 jermar 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.
3282 jermar 203
         */
4153 mejdrech 204
        nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle,
3325 jermar 205
            uint16_t_le2host(d->firstc));
2893 jermar 206
    } else {
207
        nodep->type = FAT_FILE;
3282 jermar 208
        nodep->size = uint32_t_le2host(d->size);
2893 jermar 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. */
2951 jermar 217
    nodep->idx = idxp;
218
    idxp->nodep = nodep;
2893 jermar 219
 
220
    return nodep;
2831 jermar 221
}
222
 
4153 mejdrech 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
 
2951 jermar 246
/** Instantiate a FAT in-core node. */
4153 mejdrech 247
void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
2951 jermar 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
 
4153 mejdrech 261
void fat_node_put(void *node)
2852 jermar 262
{
2910 jermar 263
    fat_node_t *nodep = (fat_node_t *)node;
4153 mejdrech 264
    bool destroy = false;
2910 jermar 265
 
2951 jermar 266
    futex_down(&nodep->lock);
2910 jermar 267
    if (!--nodep->refcnt) {
4153 mejdrech 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
        }
2910 jermar 281
    }
2951 jermar 282
    futex_up(&nodep->lock);
4153 mejdrech 283
    if (destroy)
284
        free(node);
2852 jermar 285
}
286
 
4153 mejdrech 287
void *fat_create_node(dev_handle_t dev_handle, int flags)
2857 jermar 288
{
4153 mejdrech 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;
2857 jermar 349
}
350
 
4153 mejdrech 351
int fat_destroy_node(void *node)
2857 jermar 352
{
4153 mejdrech 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;
2857 jermar 379
}
380
 
4153 mejdrech 381
int fat_link(void *prnt, void *chld, const char *name)
2857 jermar 382
{
4153 mejdrech 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 ||
4327 mejdrech 490
        str_cmp(d->name, FAT_NAME_DOT) == 0) {
4153 mejdrech 491
        memset(d, 0, sizeof(fat_dentry_t));
4327 mejdrech 492
        str_cpy(d->name, 8, FAT_NAME_DOT);
493
        str_cpy(d->ext, 3, FAT_EXT_PAD);
4153 mejdrech 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 ||
4327 mejdrech 500
        str_cmp(d->name, FAT_NAME_DOT_DOT) == 0) {
4153 mejdrech 501
        memset(d, 0, sizeof(fat_dentry_t));
4327 mejdrech 502
        str_cpy(d->name, 8, FAT_NAME_DOT_DOT);
503
        str_cpy(d->ext, 3, FAT_EXT_PAD);
4153 mejdrech 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;
2857 jermar 528
}
529
 
4153 mejdrech 530
int fat_unlink(void *prnt, void *chld)
2857 jermar 531
{
4153 mejdrech 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;
2857 jermar 568
}
569
 
4153 mejdrech 570
void *fat_match(void *prnt, const char *component)
2793 jermar 571
{
4153 mejdrech 572
    fat_bs_t *bs;
2793 jermar 573
    fat_node_t *parentp = (fat_node_t *)prnt;
574
    char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
2822 jermar 575
    unsigned i, j;
2828 jermar 576
    unsigned bps;       /* bytes per sector */
2822 jermar 577
    unsigned dps;       /* dentries per sector */
578
    unsigned blocks;
2793 jermar 579
    fat_dentry_t *d;
2822 jermar 580
    block_t *b;
2793 jermar 581
 
2953 jermar 582
    futex_down(&parentp->idx->lock);
4153 mejdrech 583
    bs = block_bb_get(parentp->idx->dev_handle);
584
    bps = uint16_t_le2host(bs->bps);
2828 jermar 585
    dps = bps / sizeof(fat_dentry_t);
4153 mejdrech 586
    blocks = parentp->size / bps;
2822 jermar 587
    for (i = 0; i < blocks; i++) {
4153 mejdrech 588
        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
589
        for (j = 0; j < dps; j++) {
2822 jermar 590
            d = ((fat_dentry_t *)b->data) + j;
2845 jermar 591
            switch (fat_classify_dentry(d)) {
592
            case FAT_DENTRY_SKIP:
4153 mejdrech 593
            case FAT_DENTRY_FREE:
2822 jermar 594
                continue;
2845 jermar 595
            case FAT_DENTRY_LAST:
2822 jermar 596
                block_put(b);
2953 jermar 597
                futex_up(&parentp->idx->lock);
2822 jermar 598
                return NULL;
2845 jermar 599
            default:
600
            case FAT_DENTRY_VALID:
4153 mejdrech 601
                fat_dentry_name_get(d, name);
2845 jermar 602
                break;
2822 jermar 603
            }
4153 mejdrech 604
            if (fat_dentry_namecmp(name, component) == 0) {
2822 jermar 605
                /* hit */
2951 jermar 606
                void *node;
2953 jermar 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
                 */
2890 jermar 613
                fat_idx_t *idx = fat_idx_get_by_pos(
2881 jermar 614
                    parentp->idx->dev_handle, parentp->firstc,
2864 jermar 615
                    i * dps + j);
2953 jermar 616
                futex_up(&parentp->idx->lock);
2890 jermar 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
                }
2951 jermar 625
                node = fat_node_get_core(idx);
626
                futex_up(&idx->lock);
2822 jermar 627
                block_put(b);
628
                return node;
629
            }
2793 jermar 630
        }
2822 jermar 631
        block_put(b);
2639 jermar 632
    }
4153 mejdrech 633
 
2953 jermar 634
    futex_up(&parentp->idx->lock);
2793 jermar 635
    return NULL;
2638 jermar 636
}
637
 
4153 mejdrech 638
fs_index_t fat_index_get(void *node)
2831 jermar 639
{
640
    fat_node_t *fnodep = (fat_node_t *)node;
641
    if (!fnodep)
642
        return 0;
2864 jermar 643
    return fnodep->idx->index;
2831 jermar 644
}
645
 
4153 mejdrech 646
size_t fat_size_get(void *node)
2831 jermar 647
{
648
    return ((fat_node_t *)node)->size;
649
}
650
 
4153 mejdrech 651
unsigned fat_lnkcnt_get(void *node)
2831 jermar 652
{
653
    return ((fat_node_t *)node)->lnkcnt;
654
}
655
 
4153 mejdrech 656
bool fat_has_children(void *node)
2845 jermar 657
{
4153 mejdrech 658
    fat_bs_t *bs;
2845 jermar 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;
4153 mejdrech 668
 
2951 jermar 669
    futex_down(&nodep->idx->lock);
4153 mejdrech 670
    bs = block_bb_get(nodep->idx->dev_handle);
671
    bps = uint16_t_le2host(bs->bps);
2845 jermar 672
    dps = bps / sizeof(fat_dentry_t);
673
 
4153 mejdrech 674
    blocks = nodep->size / bps;
2845 jermar 675
 
676
    for (i = 0; i < blocks; i++) {
677
        fat_dentry_t *d;
678
 
4153 mejdrech 679
        b = fat_block_get(bs, nodep, i, BLOCK_FLAGS_NONE);
680
        for (j = 0; j < dps; j++) {
2845 jermar 681
            d = ((fat_dentry_t *)b->data) + j;
682
            switch (fat_classify_dentry(d)) {
683
            case FAT_DENTRY_SKIP:
4153 mejdrech 684
            case FAT_DENTRY_FREE:
2845 jermar 685
                continue;
686
            case FAT_DENTRY_LAST:
687
                block_put(b);
2951 jermar 688
                futex_up(&nodep->idx->lock);
2845 jermar 689
                return false;
690
            default:
691
            case FAT_DENTRY_VALID:
692
                block_put(b);
2951 jermar 693
                futex_up(&nodep->idx->lock);
2845 jermar 694
                return true;
695
            }
696
            block_put(b);
2951 jermar 697
            futex_up(&nodep->idx->lock);
2845 jermar 698
            return true;
699
        }
700
        block_put(b);
701
    }
702
 
2951 jermar 703
    futex_up(&nodep->idx->lock);
2845 jermar 704
    return false;
705
}
706
 
4153 mejdrech 707
void *fat_root_get(dev_handle_t dev_handle)
2844 jermar 708
{
3119 jermar 709
    return fat_node_get(dev_handle, 0);
2844 jermar 710
}
711
 
4153 mejdrech 712
char fat_plb_get_char(unsigned pos)
2844 jermar 713
{
714
    return fat_reg.plb_ro[pos % PLB_SIZE];
715
}
716
 
4153 mejdrech 717
bool fat_is_directory(void *node)
2831 jermar 718
{
719
    return ((fat_node_t *)node)->type == FAT_DIRECTORY;
720
}
721
 
4153 mejdrech 722
bool fat_is_file(void *node)
2831 jermar 723
{
724
    return ((fat_node_t *)node)->type == FAT_FILE;
725
}
726
 
2793 jermar 727
/** libfs operations */
728
libfs_ops_t fat_libfs_ops = {
729
    .match = fat_match,
730
    .node_get = fat_node_get,
2852 jermar 731
    .node_put = fat_node_put,
4153 mejdrech 732
    .create = fat_create_node,
733
    .destroy = fat_destroy_node,
2857 jermar 734
    .link = fat_link,
735
    .unlink = fat_unlink,
2831 jermar 736
    .index_get = fat_index_get,
737
    .size_get = fat_size_get,
738
    .lnkcnt_get = fat_lnkcnt_get,
2845 jermar 739
    .has_children = fat_has_children,
2844 jermar 740
    .root_get = fat_root_get,
741
    .plb_get_char = fat_plb_get_char,
2831 jermar 742
    .is_directory = fat_is_directory,
743
    .is_file = fat_is_file
2793 jermar 744
};
745
 
4153 mejdrech 746
/*
747
 * VFS operations.
748
 */
749
 
3110 jermar 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);
4153 mejdrech 753
    fat_bs_t *bs;
3257 jermar 754
    uint16_t bps;
3119 jermar 755
    uint16_t rde;
3110 jermar 756
    int rc;
757
 
4327 mejdrech 758
    /* accept the mount options */
759
    ipc_callid_t callid;
760
    size_t size;
761
    if (!ipc_data_write_receive(&callid, &size)) {
762
        ipc_answer_0(callid, EINVAL);
763
        ipc_answer_0(rid, EINVAL);
764
        return;
765
    }
766
    char *opts = malloc(size + 1);
767
    if (!opts) {
768
        ipc_answer_0(callid, ENOMEM);
769
        ipc_answer_0(rid, ENOMEM);
770
        return;
771
    }
772
    ipcarg_t retval = ipc_data_write_finalize(callid, opts, size);
773
    if (retval != EOK) {
774
        ipc_answer_0(rid, retval);
775
        free(opts);
776
        return;
777
    }
778
    opts[size] = '\0';
779
 
4153 mejdrech 780
    /* initialize libblock */
781
    rc = block_init(dev_handle, BS_SIZE);
782
    if (rc != EOK) {
783
        ipc_answer_0(rid, rc);
3257 jermar 784
        return;
785
    }
786
 
4153 mejdrech 787
    /* prepare the boot block */
788
    rc = block_bb_read(dev_handle, BS_BLOCK * BS_SIZE, BS_SIZE);
3257 jermar 789
    if (rc != EOK) {
4153 mejdrech 790
        block_fini(dev_handle);
3257 jermar 791
        ipc_answer_0(rid, rc);
792
        return;
793
    }
794
 
4153 mejdrech 795
    /* get the buffer with the boot sector */
796
    bs = block_bb_get(dev_handle);
797
 
3119 jermar 798
    /* Read the number of root directory entries. */
4153 mejdrech 799
    bps = uint16_t_le2host(bs->bps);
800
    rde = uint16_t_le2host(bs->root_ent_max);
3119 jermar 801
 
3257 jermar 802
    if (bps != BS_SIZE) {
4153 mejdrech 803
        block_fini(dev_handle);
3257 jermar 804
        ipc_answer_0(rid, ENOTSUP);
805
        return;
806
    }
807
 
4153 mejdrech 808
    /* Initialize the block cache */
809
    rc = block_cache_init(dev_handle, bps, 0 /* XXX */);
810
    if (rc != EOK) {
811
        block_fini(dev_handle);
812
        ipc_answer_0(rid, rc);
813
        return;
814
    }
815
 
3110 jermar 816
    rc = fat_idx_init_by_dev_handle(dev_handle);
817
    if (rc != EOK) {
4153 mejdrech 818
        block_fini(dev_handle);
3110 jermar 819
        ipc_answer_0(rid, rc);
820
        return;
821
    }
822
 
3119 jermar 823
    /* Initialize the root node. */
824
    fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t));
825
    if (!rootp) {
4153 mejdrech 826
        block_fini(dev_handle);
3119 jermar 827
        fat_idx_fini_by_dev_handle(dev_handle);
828
        ipc_answer_0(rid, ENOMEM);
829
        return;
830
    }
831
    fat_node_initialize(rootp);
832
 
833
    fat_idx_t *ridxp = fat_idx_get_by_pos(dev_handle, FAT_CLST_ROOTPAR, 0);
834
    if (!ridxp) {
4153 mejdrech 835
        block_fini(dev_handle);
3119 jermar 836
        free(rootp);
837
        fat_idx_fini_by_dev_handle(dev_handle);
838
        ipc_answer_0(rid, ENOMEM);
839
        return;
840
    }
841
    assert(ridxp->index == 0);
842
    /* ridxp->lock held */
843
 
844
    rootp->type = FAT_DIRECTORY;
845
    rootp->firstc = FAT_CLST_ROOT;
846
    rootp->refcnt = 1;
3352 jermar 847
    rootp->lnkcnt = 0;  /* FS root is not linked */
3119 jermar 848
    rootp->size = rde * sizeof(fat_dentry_t);
849
    rootp->idx = ridxp;
850
    ridxp->nodep = rootp;
851
 
852
    futex_up(&ridxp->lock);
853
 
3352 jermar 854
    ipc_answer_3(rid, EOK, ridxp->index, rootp->size, rootp->lnkcnt);
3110 jermar 855
}
856
 
857
void fat_mount(ipc_callid_t rid, ipc_call_t *request)
858
{
859
    ipc_answer_0(rid, ENOTSUP);
860
}
861
 
2627 jermar 862
void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
863
{
2793 jermar 864
    libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
2627 jermar 865
}
866
 
3307 jermar 867
void fat_read(ipc_callid_t rid, ipc_call_t *request)
868
{
869
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
870
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
871
    off_t pos = (off_t)IPC_GET_ARG3(*request);
872
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
4153 mejdrech 873
    fat_bs_t *bs;
874
    uint16_t bps;
3308 jermar 875
    size_t bytes;
3335 jermar 876
    block_t *b;
3308 jermar 877
 
3307 jermar 878
    if (!nodep) {
879
        ipc_answer_0(rid, ENOENT);
880
        return;
881
    }
882
 
883
    ipc_callid_t callid;
884
    size_t len;
3314 jermar 885
    if (!ipc_data_read_receive(&callid, &len)) {
3307 jermar 886
        fat_node_put(nodep);
887
        ipc_answer_0(callid, EINVAL);
888
        ipc_answer_0(rid, EINVAL);
889
        return;
890
    }
891
 
4153 mejdrech 892
    bs = block_bb_get(dev_handle);
893
    bps = uint16_t_le2host(bs->bps);
894
 
3307 jermar 895
    if (nodep->type == FAT_FILE) {
3335 jermar 896
        /*
897
         * Our strategy for regular file reads is to read one block at
898
         * most and make use of the possibility to return less data than
899
         * requested. This keeps the code very simple.
900
         */
4153 mejdrech 901
        if (pos >= nodep->size) {
902
            /* reading beyond the EOF */
903
            bytes = 0;
904
            (void) ipc_data_read_finalize(callid, NULL, 0);
905
        } else {
906
            bytes = min(len, bps - pos % bps);
907
            bytes = min(bytes, nodep->size - pos);
908
            b = fat_block_get(bs, nodep, pos / bps,
909
                BLOCK_FLAGS_NONE);
910
            (void) ipc_data_read_finalize(callid, b->data + pos % bps,
911
                bytes);
912
            block_put(b);
913
        }
3307 jermar 914
    } else {
3335 jermar 915
        unsigned bnum;
916
        off_t spos = pos;
917
        char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
918
        fat_dentry_t *d;
919
 
3307 jermar 920
        assert(nodep->type == FAT_DIRECTORY);
3335 jermar 921
        assert(nodep->size % bps == 0);
922
        assert(bps % sizeof(fat_dentry_t) == 0);
923
 
924
        /*
925
         * Our strategy for readdir() is to use the position pointer as
926
         * an index into the array of all dentries. On entry, it points
927
         * to the first unread dentry. If we skip any dentries, we bump
928
         * the position pointer accordingly.
929
         */
930
        bnum = (pos * sizeof(fat_dentry_t)) / bps;
931
        while (bnum < nodep->size / bps) {
932
            off_t o;
933
 
4153 mejdrech 934
            b = fat_block_get(bs, nodep, bnum, BLOCK_FLAGS_NONE);
3335 jermar 935
            for (o = pos % (bps / sizeof(fat_dentry_t));
936
                o < bps / sizeof(fat_dentry_t);
937
                o++, pos++) {
938
                d = ((fat_dentry_t *)b->data) + o;
939
                switch (fat_classify_dentry(d)) {
940
                case FAT_DENTRY_SKIP:
4153 mejdrech 941
                case FAT_DENTRY_FREE:
3335 jermar 942
                    continue;
943
                case FAT_DENTRY_LAST:
944
                    block_put(b);
945
                    goto miss;
946
                default:
947
                case FAT_DENTRY_VALID:
4153 mejdrech 948
                    fat_dentry_name_get(d, name);
3335 jermar 949
                    block_put(b);
950
                    goto hit;
951
                }
952
            }
953
            block_put(b);
954
            bnum++;
955
        }
956
miss:
3307 jermar 957
        fat_node_put(nodep);
3335 jermar 958
        ipc_answer_0(callid, ENOENT);
959
        ipc_answer_1(rid, ENOENT, 0);
3307 jermar 960
        return;
3335 jermar 961
hit:
4327 mejdrech 962
        (void) ipc_data_read_finalize(callid, name, str_size(name) + 1);
3335 jermar 963
        bytes = (pos - spos) + 1;
3307 jermar 964
    }
965
 
966
    fat_node_put(nodep);
3308 jermar 967
    ipc_answer_1(rid, EOK, (ipcarg_t)bytes);
3307 jermar 968
}
969
 
4153 mejdrech 970
void fat_write(ipc_callid_t rid, ipc_call_t *request)
971
{
972
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
973
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
974
    off_t pos = (off_t)IPC_GET_ARG3(*request);
975
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
976
    fat_bs_t *bs;
977
    size_t bytes;
978
    block_t *b;
979
    uint16_t bps;
980
    unsigned spc;
981
    unsigned bpc;       /* bytes per cluster */
982
    off_t boundary;
983
    int flags = BLOCK_FLAGS_NONE;
984
 
985
    if (!nodep) {
986
        ipc_answer_0(rid, ENOENT);
987
        return;
988
    }
989
 
990
    ipc_callid_t callid;
991
    size_t len;
992
    if (!ipc_data_write_receive(&callid, &len)) {
993
        fat_node_put(nodep);
994
        ipc_answer_0(callid, EINVAL);
995
        ipc_answer_0(rid, EINVAL);
996
        return;
997
    }
998
 
999
    bs = block_bb_get(dev_handle);
1000
    bps = uint16_t_le2host(bs->bps);
1001
    spc = bs->spc;
1002
    bpc = bps * spc;
1003
 
1004
    /*
1005
     * In all scenarios, we will attempt to write out only one block worth
1006
     * of data at maximum. There might be some more efficient approaches,
1007
     * but this one greatly simplifies fat_write(). Note that we can afford
1008
     * to do this because the client must be ready to handle the return
1009
     * value signalizing a smaller number of bytes written.
1010
     */
1011
    bytes = min(len, bps - pos % bps);
1012
    if (bytes == bps)
1013
        flags |= BLOCK_FLAGS_NOREAD;
1014
 
1015
    boundary = ROUND_UP(nodep->size, bpc);
1016
    if (pos < boundary) {
1017
        /*
1018
         * This is the easier case - we are either overwriting already
1019
         * existing contents or writing behind the EOF, but still within
1020
         * the limits of the last cluster. The node size may grow to the
1021
         * next block size boundary.
1022
         */
1023
        fat_fill_gap(bs, nodep, FAT_CLST_RES0, pos);
1024
        b = fat_block_get(bs, nodep, pos / bps, flags);
1025
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
1026
            bytes);
1027
        b->dirty = true;        /* need to sync block */
1028
        block_put(b);
1029
        if (pos + bytes > nodep->size) {
1030
            nodep->size = pos + bytes;
1031
            nodep->dirty = true;    /* need to sync node */
1032
        }
1033
        ipc_answer_2(rid, EOK, bytes, nodep->size);
1034
        fat_node_put(nodep);
1035
        return;
1036
    } else {
1037
        /*
1038
         * This is the more difficult case. We must allocate new
1039
         * clusters for the node and zero them out.
1040
         */
1041
        int status;
1042
        unsigned nclsts;
1043
        fat_cluster_t mcl, lcl;
1044
 
1045
        nclsts = (ROUND_UP(pos + bytes, bpc) - boundary) / bpc;
1046
        /* create an independent chain of nclsts clusters in all FATs */
1047
        status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl, &lcl);
1048
        if (status != EOK) {
1049
            /* could not allocate a chain of nclsts clusters */
1050
            fat_node_put(nodep);
1051
            ipc_answer_0(callid, status);
1052
            ipc_answer_0(rid, status);
1053
            return;
1054
        }
1055
        /* zero fill any gaps */
1056
        fat_fill_gap(bs, nodep, mcl, pos);
1057
        b = _fat_block_get(bs, dev_handle, lcl, (pos / bps) % spc,
1058
            flags);
1059
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
1060
            bytes);
1061
        b->dirty = true;        /* need to sync block */
1062
        block_put(b);
1063
        /*
1064
         * Append the cluster chain starting in mcl to the end of the
1065
         * node's cluster chain.
1066
         */
1067
        fat_append_clusters(bs, nodep, mcl);
1068
        nodep->size = pos + bytes;
1069
        nodep->dirty = true;        /* need to sync node */
1070
        ipc_answer_2(rid, EOK, bytes, nodep->size);
1071
        fat_node_put(nodep);
1072
        return;
1073
    }
1074
}
1075
 
1076
void fat_truncate(ipc_callid_t rid, ipc_call_t *request)
1077
{
1078
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
1079
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
1080
    size_t size = (off_t)IPC_GET_ARG3(*request);
1081
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
1082
    fat_bs_t *bs;
1083
    uint16_t bps;
1084
    uint8_t spc;
1085
    unsigned bpc;   /* bytes per cluster */
1086
    int rc;
1087
 
1088
    if (!nodep) {
1089
        ipc_answer_0(rid, ENOENT);
1090
        return;
1091
    }
1092
 
1093
    bs = block_bb_get(dev_handle);
1094
    bps = uint16_t_le2host(bs->bps);
1095
    spc = bs->spc;
1096
    bpc = bps * spc;
1097
 
1098
    if (nodep->size == size) {
1099
        rc = EOK;
1100
    } else if (nodep->size < size) {
1101
        /*
1102
         * The standard says we have the freedom to grow the node.
1103
         * For now, we simply return an error.
1104
         */
1105
        rc = EINVAL;
1106
    } else if (ROUND_UP(nodep->size, bpc) == ROUND_UP(size, bpc)) {
1107
        /*
1108
         * The node will be shrunk, but no clusters will be deallocated.
1109
         */
1110
        nodep->size = size;
1111
        nodep->dirty = true;        /* need to sync node */
1112
        rc = EOK;  
1113
    } else {
1114
        /*
1115
         * The node will be shrunk, clusters will be deallocated.
1116
         */
1117
        if (size == 0) {
1118
            fat_chop_clusters(bs, nodep, FAT_CLST_RES0);
1119
        } else {
1120
            fat_cluster_t lastc;
1121
            (void) fat_cluster_walk(bs, dev_handle, nodep->firstc,
1122
                &lastc, (size - 1) / bpc);
1123
            fat_chop_clusters(bs, nodep, lastc);
1124
        }
1125
        nodep->size = size;
1126
        nodep->dirty = true;        /* need to sync node */
1127
        rc = EOK;  
1128
    }
1129
    fat_node_put(nodep);
1130
    ipc_answer_0(rid, rc);
1131
    return;
1132
}
1133
 
1134
void fat_destroy(ipc_callid_t rid, ipc_call_t *request)
1135
{
1136
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
1137
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
1138
    int rc;
1139
 
1140
    fat_node_t *nodep = fat_node_get(dev_handle, index);
1141
    if (!nodep) {
1142
        ipc_answer_0(rid, ENOENT);
1143
        return;
1144
    }
1145
 
1146
    rc = fat_destroy_node(nodep);
1147
    ipc_answer_0(rid, rc);
1148
}
1149
 
2627 jermar 1150
/**
1151
 * @}
1152
 */