Subversion Repositories HelenOS

Rev

Rev 3598 | Rev 4348 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
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"
3535 svoboda 39
#include "fat_dentry.h"
40
#include "fat_fat.h"
2638 jermar 41
#include "../../vfs/vfs.h"
2793 jermar 42
#include <libfs.h>
3535 svoboda 43
#include <libblock.h>
2627 jermar 44
#include <ipc/ipc.h>
3403 svoboda 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>
3403 svoboda 55
#include <sys/mman.h>
3535 svoboda 56
#include <align.h>
2627 jermar 57
 
3009 svoboda 58
/** Futex protecting the list of cached free FAT nodes. */
59
static futex_t ffn_futex = FUTEX_INITIALIZER;
2843 jermar 60
 
3009 svoboda 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
{
3009 svoboda 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
 
3535 svoboda 76
static void fat_node_sync(fat_node_t *node)
2843 jermar 77
{
3535 svoboda 78
    block_t *b;
79
    fat_bs_t *bs;
80
    fat_dentry_t *d;
2843 jermar 81
    uint16_t bps;
3535 svoboda 82
    unsigned dps;
2843 jermar 83
 
3535 svoboda 84
    assert(node->dirty);
2843 jermar 85
 
3535 svoboda 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,
3598 svoboda 92
        (node->idx->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
2843 jermar 93
 
3535 svoboda 94
    d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps);
2845 jermar 95
 
3535 svoboda 96
    d->firstc = host2uint16_t_le(node->firstc);
3674 svoboda 97
    if (node->type == FAT_FILE) {
3535 svoboda 98
        d->size = host2uint32_t_le(node->size);
3674 svoboda 99
    } else if (node->type == FAT_DIRECTORY) {
100
        d->attr = FAT_ATTR_SUBDIR;
101
    }
3535 svoboda 102
 
3674 svoboda 103
    /* TODO: update other fields? (e.g time fields) */
104
 
3535 svoboda 105
    b->dirty = true;        /* need to sync block */
106
    block_put(b);
2845 jermar 107
}
108
 
3588 svoboda 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
 
3009 svoboda 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;
3535 svoboda 152
    fat_bs_t *bs;
2891 jermar 153
    fat_dentry_t *d;
3403 svoboda 154
    fat_node_t *nodep = NULL;
2891 jermar 155
    unsigned bps;
3561 svoboda 156
    unsigned spc;
2891 jermar 157
    unsigned dps;
158
 
3009 svoboda 159
    if (idxp->nodep) {
2891 jermar 160
        /*
161
         * We are lucky.
162
         * The node is already instantiated in memory.
163
         */
3009 svoboda 164
        futex_down(&idxp->nodep->lock);
165
        if (!idxp->nodep->refcnt++)
3403 svoboda 166
            list_remove(&idxp->nodep->ffn_link);
3009 svoboda 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
 
3009 svoboda 175
    assert(idxp->pfc);
2891 jermar 176
 
3588 svoboda 177
    nodep = fat_node_get_new();
178
    if (!nodep)
179
        return NULL;
2891 jermar 180
 
3535 svoboda 181
    bs = block_bb_get(idxp->dev_handle);
182
    bps = uint16_t_le2host(bs->bps);
3561 svoboda 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. */
3535 svoboda 187
    b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc,
3598 svoboda 188
        (idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE);
2891 jermar 189
    assert(b);
190
 
3009 svoboda 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;
3403 svoboda 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
         */
3561 svoboda 204
        nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle,
205
            uint16_t_le2host(d->firstc));
2893 jermar 206
    } else {
207
        nodep->type = FAT_FILE;
3403 svoboda 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. */
3009 svoboda 217
    nodep->idx = idxp;
218
    idxp->nodep = nodep;
2893 jermar 219
 
220
    return nodep;
2831 jermar 221
}
222
 
3674 svoboda 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
 
3009 svoboda 246
/** Instantiate a FAT in-core node. */
3674 svoboda 247
void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
3009 svoboda 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
 
3674 svoboda 261
void fat_node_put(void *node)
2852 jermar 262
{
2910 jermar 263
    fat_node_t *nodep = (fat_node_t *)node;
3674 svoboda 264
    bool destroy = false;
2910 jermar 265
 
3009 svoboda 266
    futex_down(&nodep->lock);
2910 jermar 267
    if (!--nodep->refcnt) {
3674 svoboda 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
    }
3009 svoboda 282
    futex_up(&nodep->lock);
3674 svoboda 283
    if (destroy)
284
        free(node);
2852 jermar 285
}
286
 
3674 svoboda 287
void *fat_create_node(dev_handle_t dev_handle, int flags)
2857 jermar 288
{
3674 svoboda 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
 
3674 svoboda 351
int fat_destroy_node(void *node)
2857 jermar 352
{
3674 svoboda 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
 
3674 svoboda 381
int fat_link(void *prnt, void *chld, const char *name)
2857 jermar 382
{
3674 svoboda 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
 
393
    futex_down(&childp->lock);
394
    if (childp->lnkcnt == 1) {
395
        /*
396
         * On FAT, we don't support multiple hard links.
397
         */
398
        futex_up(&childp->lock);
399
        return EMLINK;
400
    }
401
    assert(childp->lnkcnt == 0);
402
    futex_up(&childp->lock);
403
 
404
    if (!fat_dentry_name_verify(name)) {
405
        /*
406
         * Attempt to create unsupported name.
407
         */
408
        return ENOTSUP;
409
    }
410
 
411
    /*
412
     * Get us an unused parent node's dentry or grow the parent and allocate
413
     * a new one.
414
     */
415
 
416
    futex_down(&parentp->idx->lock);
417
    bs = block_bb_get(parentp->idx->dev_handle);
418
    bps = uint16_t_le2host(bs->bps);
419
    dps = bps / sizeof(fat_dentry_t);
420
 
421
    blocks = parentp->size / bps;
422
 
423
    for (i = 0; i < blocks; i++) {
424
        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
425
        for (j = 0; j < dps; j++) {
426
            d = ((fat_dentry_t *)b->data) + j;
427
            switch (fat_classify_dentry(d)) {
428
            case FAT_DENTRY_SKIP:
429
            case FAT_DENTRY_VALID:
430
                /* skipping used and meta entries */
431
                continue;
432
            case FAT_DENTRY_FREE:
433
            case FAT_DENTRY_LAST:
434
                /* found an empty slot */
435
                goto hit;
436
            }
437
        }
438
        block_put(b);
439
    }
440
 
441
    /*
442
     * We need to grow the parent in order to create a new unused dentry.
443
     */
444
    futex_up(&parentp->idx->lock);
445
    return ENOTSUP; /* XXX */
446
 
447
hit:
448
    /*
449
     * At this point we only establish the link between the parent and the
450
     * child.  The dentry, except of the name and the extension, will remain
451
     * uninitialized until the the corresponding node is synced. Thus the
452
     * valid dentry data is kept in the child node structure.
453
     */
454
    memset(d, 0, sizeof(fat_dentry_t));
455
    fat_dentry_name_set(d, name);
456
    b->dirty = true;        /* need to sync block */
457
    block_put(b);
458
    futex_up(&parentp->idx->lock);
459
 
460
    futex_down(&childp->idx->lock);
461
 
462
    /*
463
     * If possible, create the Sub-directory Identifier Entry and the
464
     * Sub-directory Parent Pointer Entry (i.e. "." and ".."). These entries
465
     * are not mandatory according to Standard ECMA-107 and HelenOS VFS does
466
     * not use them anyway, so this is rather a sign of our good will.
467
     */
468
    b = fat_block_get(bs, childp, 0, BLOCK_FLAGS_NONE);
469
    d = (fat_dentry_t *)b->data;
470
    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
471
        strcmp(d->name, FAT_NAME_DOT) == 0) {
472
        memset(d, 0, sizeof(fat_dentry_t));
473
        strcpy(d->name, FAT_NAME_DOT);
474
        strcpy(d->ext, FAT_EXT_PAD);
475
        d->attr = FAT_ATTR_SUBDIR;
476
        d->firstc = host2uint16_t_le(childp->firstc);
477
        /* TODO: initialize also the date/time members. */
478
    }
479
    d++;
480
    if (fat_classify_dentry(d) == FAT_DENTRY_LAST ||
481
        strcmp(d->name, FAT_NAME_DOT_DOT) == 0) {
482
        memset(d, 0, sizeof(fat_dentry_t));
483
        strcpy(d->name, FAT_NAME_DOT_DOT);
484
        strcpy(d->ext, FAT_EXT_PAD);
485
        d->attr = FAT_ATTR_SUBDIR;
486
        d->firstc = (parentp->firstc == FAT_CLST_ROOT) ?
487
            host2uint16_t_le(FAT_CLST_RES0) :
488
            host2uint16_t_le(parentp->firstc);
489
        /* TODO: initialize also the date/time members. */
490
    }
491
    b->dirty = true;        /* need to sync block */
492
    block_put(b);
493
 
494
    childp->idx->pfc = parentp->firstc;
495
    childp->idx->pdi = i * dps + j;
496
    futex_up(&childp->idx->lock);
497
 
498
    futex_down(&childp->lock);
499
    childp->lnkcnt = 1;
500
    childp->dirty = true;       /* need to sync node */
501
    futex_up(&childp->lock);
502
 
503
    /*
504
     * Hash in the index structure into the position hash.
505
     */
506
    fat_idx_hashin(childp->idx);
507
 
508
    return EOK;
2857 jermar 509
}
510
 
3674 svoboda 511
int fat_unlink(void *prnt, void *chld)
2857 jermar 512
{
3674 svoboda 513
    fat_node_t *parentp = (fat_node_t *)prnt;
514
    fat_node_t *childp = (fat_node_t *)chld;
515
    fat_bs_t *bs;
516
    fat_dentry_t *d;
517
    uint16_t bps;
518
    block_t *b;
519
 
520
    futex_down(&parentp->lock);
521
    futex_down(&childp->lock);
522
    assert(childp->lnkcnt == 1);
523
    futex_down(&childp->idx->lock);
524
    bs = block_bb_get(childp->idx->dev_handle);
525
    bps = uint16_t_le2host(bs->bps);
526
 
527
    b = _fat_block_get(bs, childp->idx->dev_handle, childp->idx->pfc,
528
        (childp->idx->pdi * sizeof(fat_dentry_t)) / bps,
529
        BLOCK_FLAGS_NONE);
530
    d = (fat_dentry_t *)b->data +
531
        (childp->idx->pdi % (bps / sizeof(fat_dentry_t)));
532
    /* mark the dentry as not-currently-used */
533
    d->name[0] = FAT_DENTRY_ERASED;
534
    b->dirty = true;        /* need to sync block */
535
    block_put(b);
536
 
537
    /* remove the index structure from the position hash */
538
    fat_idx_hashout(childp->idx);
539
    /* clear position information */
540
    childp->idx->pfc = FAT_CLST_RES0;
541
    childp->idx->pdi = 0;
542
    futex_up(&childp->idx->lock);
543
    childp->lnkcnt = 0;
544
    childp->dirty = true;
545
    futex_up(&childp->lock);
546
    futex_up(&parentp->lock);
547
 
548
    return EOK;
2857 jermar 549
}
550
 
3674 svoboda 551
void *fat_match(void *prnt, const char *component)
2793 jermar 552
{
3535 svoboda 553
    fat_bs_t *bs;
2793 jermar 554
    fat_node_t *parentp = (fat_node_t *)prnt;
555
    char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
2822 jermar 556
    unsigned i, j;
2828 jermar 557
    unsigned bps;       /* bytes per sector */
2822 jermar 558
    unsigned dps;       /* dentries per sector */
559
    unsigned blocks;
2793 jermar 560
    fat_dentry_t *d;
2822 jermar 561
    block_t *b;
2793 jermar 562
 
3009 svoboda 563
    futex_down(&parentp->idx->lock);
3535 svoboda 564
    bs = block_bb_get(parentp->idx->dev_handle);
565
    bps = uint16_t_le2host(bs->bps);
2828 jermar 566
    dps = bps / sizeof(fat_dentry_t);
3535 svoboda 567
    blocks = parentp->size / bps;
2822 jermar 568
    for (i = 0; i < blocks; i++) {
3598 svoboda 569
        b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE);
3535 svoboda 570
        for (j = 0; j < dps; j++) {
2822 jermar 571
            d = ((fat_dentry_t *)b->data) + j;
2845 jermar 572
            switch (fat_classify_dentry(d)) {
573
            case FAT_DENTRY_SKIP:
3674 svoboda 574
            case FAT_DENTRY_FREE:
2822 jermar 575
                continue;
2845 jermar 576
            case FAT_DENTRY_LAST:
2822 jermar 577
                block_put(b);
3009 svoboda 578
                futex_up(&parentp->idx->lock);
2822 jermar 579
                return NULL;
2845 jermar 580
            default:
581
            case FAT_DENTRY_VALID:
3674 svoboda 582
                fat_dentry_name_get(d, name);
2845 jermar 583
                break;
2822 jermar 584
            }
3674 svoboda 585
            if (fat_dentry_namecmp(name, component) == 0) {
2822 jermar 586
                /* hit */
3009 svoboda 587
                void *node;
588
                /*
589
                 * Assume tree hierarchy for locking.  We
590
                 * already have the parent and now we are going
591
                 * to lock the child.  Never lock in the oposite
592
                 * order.
593
                 */
2890 jermar 594
                fat_idx_t *idx = fat_idx_get_by_pos(
2881 jermar 595
                    parentp->idx->dev_handle, parentp->firstc,
2864 jermar 596
                    i * dps + j);
3009 svoboda 597
                futex_up(&parentp->idx->lock);
2890 jermar 598
                if (!idx) {
599
                    /*
600
                     * Can happen if memory is low or if we
601
                     * run out of 32-bit indices.
602
                     */
603
                    block_put(b);
604
                    return NULL;
605
                }
3009 svoboda 606
                node = fat_node_get_core(idx);
607
                futex_up(&idx->lock);
2822 jermar 608
                block_put(b);
609
                return node;
610
            }
2793 jermar 611
        }
2822 jermar 612
        block_put(b);
2639 jermar 613
    }
3535 svoboda 614
 
3009 svoboda 615
    futex_up(&parentp->idx->lock);
2793 jermar 616
    return NULL;
2638 jermar 617
}
618
 
3674 svoboda 619
fs_index_t fat_index_get(void *node)
2831 jermar 620
{
621
    fat_node_t *fnodep = (fat_node_t *)node;
622
    if (!fnodep)
623
        return 0;
2864 jermar 624
    return fnodep->idx->index;
2831 jermar 625
}
626
 
3674 svoboda 627
size_t fat_size_get(void *node)
2831 jermar 628
{
629
    return ((fat_node_t *)node)->size;
630
}
631
 
3674 svoboda 632
unsigned fat_lnkcnt_get(void *node)
2831 jermar 633
{
634
    return ((fat_node_t *)node)->lnkcnt;
635
}
636
 
3674 svoboda 637
bool fat_has_children(void *node)
2845 jermar 638
{
3535 svoboda 639
    fat_bs_t *bs;
2845 jermar 640
    fat_node_t *nodep = (fat_node_t *)node;
641
    unsigned bps;
642
    unsigned dps;
643
    unsigned blocks;
644
    block_t *b;
645
    unsigned i, j;
646
 
647
    if (nodep->type != FAT_DIRECTORY)
648
        return false;
3535 svoboda 649
 
3009 svoboda 650
    futex_down(&nodep->idx->lock);
3535 svoboda 651
    bs = block_bb_get(nodep->idx->dev_handle);
652
    bps = uint16_t_le2host(bs->bps);
2845 jermar 653
    dps = bps / sizeof(fat_dentry_t);
654
 
3535 svoboda 655
    blocks = nodep->size / bps;
2845 jermar 656
 
657
    for (i = 0; i < blocks; i++) {
658
        fat_dentry_t *d;
659
 
3598 svoboda 660
        b = fat_block_get(bs, nodep, i, BLOCK_FLAGS_NONE);
3535 svoboda 661
        for (j = 0; j < dps; j++) {
2845 jermar 662
            d = ((fat_dentry_t *)b->data) + j;
663
            switch (fat_classify_dentry(d)) {
664
            case FAT_DENTRY_SKIP:
3674 svoboda 665
            case FAT_DENTRY_FREE:
2845 jermar 666
                continue;
667
            case FAT_DENTRY_LAST:
668
                block_put(b);
3009 svoboda 669
                futex_up(&nodep->idx->lock);
2845 jermar 670
                return false;
671
            default:
672
            case FAT_DENTRY_VALID:
673
                block_put(b);
3009 svoboda 674
                futex_up(&nodep->idx->lock);
2845 jermar 675
                return true;
676
            }
677
            block_put(b);
3009 svoboda 678
            futex_up(&nodep->idx->lock);
2845 jermar 679
            return true;
680
        }
681
        block_put(b);
682
    }
683
 
3009 svoboda 684
    futex_up(&nodep->idx->lock);
2845 jermar 685
    return false;
686
}
687
 
3674 svoboda 688
void *fat_root_get(dev_handle_t dev_handle)
2844 jermar 689
{
3153 svoboda 690
    return fat_node_get(dev_handle, 0);
2844 jermar 691
}
692
 
3674 svoboda 693
char fat_plb_get_char(unsigned pos)
2844 jermar 694
{
695
    return fat_reg.plb_ro[pos % PLB_SIZE];
696
}
697
 
3674 svoboda 698
bool fat_is_directory(void *node)
2831 jermar 699
{
700
    return ((fat_node_t *)node)->type == FAT_DIRECTORY;
701
}
702
 
3674 svoboda 703
bool fat_is_file(void *node)
2831 jermar 704
{
705
    return ((fat_node_t *)node)->type == FAT_FILE;
706
}
707
 
2793 jermar 708
/** libfs operations */
709
libfs_ops_t fat_libfs_ops = {
710
    .match = fat_match,
711
    .node_get = fat_node_get,
2852 jermar 712
    .node_put = fat_node_put,
3674 svoboda 713
    .create = fat_create_node,
714
    .destroy = fat_destroy_node,
2857 jermar 715
    .link = fat_link,
716
    .unlink = fat_unlink,
2831 jermar 717
    .index_get = fat_index_get,
718
    .size_get = fat_size_get,
719
    .lnkcnt_get = fat_lnkcnt_get,
2845 jermar 720
    .has_children = fat_has_children,
2844 jermar 721
    .root_get = fat_root_get,
722
    .plb_get_char = fat_plb_get_char,
2831 jermar 723
    .is_directory = fat_is_directory,
724
    .is_file = fat_is_file
2793 jermar 725
};
726
 
3674 svoboda 727
/*
728
 * VFS operations.
729
 */
730
 
3153 svoboda 731
void fat_mounted(ipc_callid_t rid, ipc_call_t *request)
732
{
733
    dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
3535 svoboda 734
    fat_bs_t *bs;
3403 svoboda 735
    uint16_t bps;
3153 svoboda 736
    uint16_t rde;
737
    int rc;
738
 
3535 svoboda 739
    /* initialize libblock */
3561 svoboda 740
    rc = block_init(dev_handle, BS_SIZE);
3403 svoboda 741
    if (rc != EOK) {
3561 svoboda 742
        ipc_answer_0(rid, rc);
3403 svoboda 743
        return;
744
    }
745
 
3561 svoboda 746
    /* prepare the boot block */
747
    rc = block_bb_read(dev_handle, BS_BLOCK * BS_SIZE, BS_SIZE);
748
    if (rc != EOK) {
749
        block_fini(dev_handle);
750
        ipc_answer_0(rid, rc);
751
        return;
752
    }
753
 
3535 svoboda 754
    /* get the buffer with the boot sector */
755
    bs = block_bb_get(dev_handle);
756
 
3153 svoboda 757
    /* Read the number of root directory entries. */
3535 svoboda 758
    bps = uint16_t_le2host(bs->bps);
759
    rde = uint16_t_le2host(bs->root_ent_max);
3153 svoboda 760
 
3403 svoboda 761
    if (bps != BS_SIZE) {
3535 svoboda 762
        block_fini(dev_handle);
3403 svoboda 763
        ipc_answer_0(rid, ENOTSUP);
764
        return;
765
    }
766
 
3561 svoboda 767
    /* Initialize the block cache */
768
    rc = block_cache_init(dev_handle, bps, 0 /* XXX */);
769
    if (rc != EOK) {
770
        block_fini(dev_handle);
771
        ipc_answer_0(rid, rc);
772
        return;
773
    }
774
 
3153 svoboda 775
    rc = fat_idx_init_by_dev_handle(dev_handle);
776
    if (rc != EOK) {
3535 svoboda 777
        block_fini(dev_handle);
3153 svoboda 778
        ipc_answer_0(rid, rc);
779
        return;
780
    }
781
 
782
    /* Initialize the root node. */
783
    fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t));
784
    if (!rootp) {
3535 svoboda 785
        block_fini(dev_handle);
3153 svoboda 786
        fat_idx_fini_by_dev_handle(dev_handle);
787
        ipc_answer_0(rid, ENOMEM);
788
        return;
789
    }
790
    fat_node_initialize(rootp);
791
 
792
    fat_idx_t *ridxp = fat_idx_get_by_pos(dev_handle, FAT_CLST_ROOTPAR, 0);
793
    if (!ridxp) {
3535 svoboda 794
        block_fini(dev_handle);
3153 svoboda 795
        free(rootp);
796
        fat_idx_fini_by_dev_handle(dev_handle);
797
        ipc_answer_0(rid, ENOMEM);
798
        return;
799
    }
800
    assert(ridxp->index == 0);
801
    /* ridxp->lock held */
802
 
803
    rootp->type = FAT_DIRECTORY;
804
    rootp->firstc = FAT_CLST_ROOT;
805
    rootp->refcnt = 1;
3403 svoboda 806
    rootp->lnkcnt = 0;  /* FS root is not linked */
3153 svoboda 807
    rootp->size = rde * sizeof(fat_dentry_t);
808
    rootp->idx = ridxp;
809
    ridxp->nodep = rootp;
810
 
811
    futex_up(&ridxp->lock);
812
 
3403 svoboda 813
    ipc_answer_3(rid, EOK, ridxp->index, rootp->size, rootp->lnkcnt);
3153 svoboda 814
}
815
 
816
void fat_mount(ipc_callid_t rid, ipc_call_t *request)
817
{
818
    ipc_answer_0(rid, ENOTSUP);
819
}
820
 
2627 jermar 821
void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
822
{
2793 jermar 823
    libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
2627 jermar 824
}
825
 
3403 svoboda 826
void fat_read(ipc_callid_t rid, ipc_call_t *request)
827
{
828
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
829
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
830
    off_t pos = (off_t)IPC_GET_ARG3(*request);
831
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
3535 svoboda 832
    fat_bs_t *bs;
833
    uint16_t bps;
3403 svoboda 834
    size_t bytes;
835
    block_t *b;
836
 
837
    if (!nodep) {
838
        ipc_answer_0(rid, ENOENT);
839
        return;
840
    }
841
 
842
    ipc_callid_t callid;
843
    size_t len;
844
    if (!ipc_data_read_receive(&callid, &len)) {
845
        fat_node_put(nodep);
846
        ipc_answer_0(callid, EINVAL);
847
        ipc_answer_0(rid, EINVAL);
848
        return;
849
    }
850
 
3535 svoboda 851
    bs = block_bb_get(dev_handle);
852
    bps = uint16_t_le2host(bs->bps);
853
 
3403 svoboda 854
    if (nodep->type == FAT_FILE) {
855
        /*
856
         * Our strategy for regular file reads is to read one block at
857
         * most and make use of the possibility to return less data than
858
         * requested. This keeps the code very simple.
859
         */
3535 svoboda 860
        if (pos >= nodep->size) {
861
            /* reading beyond the EOF */
862
            bytes = 0;
863
            (void) ipc_data_read_finalize(callid, NULL, 0);
864
        } else {
865
            bytes = min(len, bps - pos % bps);
866
            bytes = min(bytes, nodep->size - pos);
3598 svoboda 867
            b = fat_block_get(bs, nodep, pos / bps,
868
                BLOCK_FLAGS_NONE);
3535 svoboda 869
            (void) ipc_data_read_finalize(callid, b->data + pos % bps,
870
                bytes);
871
            block_put(b);
872
        }
3403 svoboda 873
    } else {
874
        unsigned bnum;
875
        off_t spos = pos;
876
        char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
877
        fat_dentry_t *d;
878
 
879
        assert(nodep->type == FAT_DIRECTORY);
880
        assert(nodep->size % bps == 0);
881
        assert(bps % sizeof(fat_dentry_t) == 0);
882
 
883
        /*
884
         * Our strategy for readdir() is to use the position pointer as
885
         * an index into the array of all dentries. On entry, it points
886
         * to the first unread dentry. If we skip any dentries, we bump
887
         * the position pointer accordingly.
888
         */
889
        bnum = (pos * sizeof(fat_dentry_t)) / bps;
890
        while (bnum < nodep->size / bps) {
891
            off_t o;
892
 
3598 svoboda 893
            b = fat_block_get(bs, nodep, bnum, BLOCK_FLAGS_NONE);
3403 svoboda 894
            for (o = pos % (bps / sizeof(fat_dentry_t));
895
                o < bps / sizeof(fat_dentry_t);
896
                o++, pos++) {
897
                d = ((fat_dentry_t *)b->data) + o;
898
                switch (fat_classify_dentry(d)) {
899
                case FAT_DENTRY_SKIP:
3674 svoboda 900
                case FAT_DENTRY_FREE:
3403 svoboda 901
                    continue;
902
                case FAT_DENTRY_LAST:
903
                    block_put(b);
904
                    goto miss;
905
                default:
906
                case FAT_DENTRY_VALID:
3674 svoboda 907
                    fat_dentry_name_get(d, name);
3403 svoboda 908
                    block_put(b);
909
                    goto hit;
910
                }
911
            }
912
            block_put(b);
913
            bnum++;
914
        }
915
miss:
916
        fat_node_put(nodep);
917
        ipc_answer_0(callid, ENOENT);
918
        ipc_answer_1(rid, ENOENT, 0);
919
        return;
920
hit:
921
        (void) ipc_data_read_finalize(callid, name, strlen(name) + 1);
922
        bytes = (pos - spos) + 1;
923
    }
924
 
925
    fat_node_put(nodep);
926
    ipc_answer_1(rid, EOK, (ipcarg_t)bytes);
927
}
928
 
3535 svoboda 929
void fat_write(ipc_callid_t rid, ipc_call_t *request)
930
{
931
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
932
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
933
    off_t pos = (off_t)IPC_GET_ARG3(*request);
934
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
935
    fat_bs_t *bs;
936
    size_t bytes;
937
    block_t *b;
938
    uint16_t bps;
939
    unsigned spc;
3588 svoboda 940
    unsigned bpc;       /* bytes per cluster */
3535 svoboda 941
    off_t boundary;
3598 svoboda 942
    int flags = BLOCK_FLAGS_NONE;
3535 svoboda 943
 
944
    if (!nodep) {
945
        ipc_answer_0(rid, ENOENT);
946
        return;
947
    }
948
 
949
    ipc_callid_t callid;
950
    size_t len;
951
    if (!ipc_data_write_receive(&callid, &len)) {
952
        fat_node_put(nodep);
953
        ipc_answer_0(callid, EINVAL);
954
        ipc_answer_0(rid, EINVAL);
955
        return;
956
    }
957
 
3588 svoboda 958
    bs = block_bb_get(dev_handle);
959
    bps = uint16_t_le2host(bs->bps);
960
    spc = bs->spc;
961
    bpc = bps * spc;
962
 
3535 svoboda 963
    /*
964
     * In all scenarios, we will attempt to write out only one block worth
965
     * of data at maximum. There might be some more efficient approaches,
966
     * but this one greatly simplifies fat_write(). Note that we can afford
967
     * to do this because the client must be ready to handle the return
968
     * value signalizing a smaller number of bytes written.
969
     */
970
    bytes = min(len, bps - pos % bps);
3598 svoboda 971
    if (bytes == bps)
972
        flags |= BLOCK_FLAGS_NOREAD;
3535 svoboda 973
 
3588 svoboda 974
    boundary = ROUND_UP(nodep->size, bpc);
3535 svoboda 975
    if (pos < boundary) {
976
        /*
977
         * This is the easier case - we are either overwriting already
978
         * existing contents or writing behind the EOF, but still within
979
         * the limits of the last cluster. The node size may grow to the
980
         * next block size boundary.
981
         */
982
        fat_fill_gap(bs, nodep, FAT_CLST_RES0, pos);
3598 svoboda 983
        b = fat_block_get(bs, nodep, pos / bps, flags);
3535 svoboda 984
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
985
            bytes);
986
        b->dirty = true;        /* need to sync block */
987
        block_put(b);
988
        if (pos + bytes > nodep->size) {
989
            nodep->size = pos + bytes;
990
            nodep->dirty = true;    /* need to sync node */
991
        }
3588 svoboda 992
        ipc_answer_2(rid, EOK, bytes, nodep->size);
3535 svoboda 993
        fat_node_put(nodep);
994
        return;
995
    } else {
996
        /*
997
         * This is the more difficult case. We must allocate new
998
         * clusters for the node and zero them out.
999
         */
1000
        int status;
1001
        unsigned nclsts;
3561 svoboda 1002
        fat_cluster_t mcl, lcl;
1003
 
3588 svoboda 1004
        nclsts = (ROUND_UP(pos + bytes, bpc) - boundary) / bpc;
3535 svoboda 1005
        /* create an independent chain of nclsts clusters in all FATs */
3588 svoboda 1006
        status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl, &lcl);
3535 svoboda 1007
        if (status != EOK) {
1008
            /* could not allocate a chain of nclsts clusters */
1009
            fat_node_put(nodep);
1010
            ipc_answer_0(callid, status);
1011
            ipc_answer_0(rid, status);
1012
            return;
1013
        }
1014
        /* zero fill any gaps */
1015
        fat_fill_gap(bs, nodep, mcl, pos);
3598 svoboda 1016
        b = _fat_block_get(bs, dev_handle, lcl, (pos / bps) % spc,
1017
            flags);
3535 svoboda 1018
        (void) ipc_data_write_finalize(callid, b->data + pos % bps,
1019
            bytes);
1020
        b->dirty = true;        /* need to sync block */
1021
        block_put(b);
1022
        /*
1023
         * Append the cluster chain starting in mcl to the end of the
1024
         * node's cluster chain.
1025
         */
1026
        fat_append_clusters(bs, nodep, mcl);
1027
        nodep->size = pos + bytes;
1028
        nodep->dirty = true;        /* need to sync node */
3588 svoboda 1029
        ipc_answer_2(rid, EOK, bytes, nodep->size);
3535 svoboda 1030
        fat_node_put(nodep);
1031
        return;
1032
    }
1033
}
1034
 
3561 svoboda 1035
void fat_truncate(ipc_callid_t rid, ipc_call_t *request)
1036
{
1037
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
1038
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
1039
    size_t size = (off_t)IPC_GET_ARG3(*request);
1040
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
3588 svoboda 1041
    fat_bs_t *bs;
1042
    uint16_t bps;
1043
    uint8_t spc;
1044
    unsigned bpc;   /* bytes per cluster */
3561 svoboda 1045
    int rc;
1046
 
1047
    if (!nodep) {
1048
        ipc_answer_0(rid, ENOENT);
1049
        return;
1050
    }
1051
 
3588 svoboda 1052
    bs = block_bb_get(dev_handle);
1053
    bps = uint16_t_le2host(bs->bps);
1054
    spc = bs->spc;
1055
    bpc = bps * spc;
1056
 
3561 svoboda 1057
    if (nodep->size == size) {
1058
        rc = EOK;
1059
    } else if (nodep->size < size) {
1060
        /*
3588 svoboda 1061
         * The standard says we have the freedom to grow the node.
3561 svoboda 1062
         * For now, we simply return an error.
1063
         */
1064
        rc = EINVAL;
3588 svoboda 1065
    } else if (ROUND_UP(nodep->size, bpc) == ROUND_UP(size, bpc)) {
1066
        /*
1067
         * The node will be shrunk, but no clusters will be deallocated.
1068
         */
1069
        nodep->size = size;
1070
        nodep->dirty = true;        /* need to sync node */
1071
        rc = EOK;  
3561 svoboda 1072
    } else {
1073
        /*
3588 svoboda 1074
         * The node will be shrunk, clusters will be deallocated.
3561 svoboda 1075
         */
3588 svoboda 1076
        if (size == 0) {
1077
            fat_chop_clusters(bs, nodep, FAT_CLST_RES0);
1078
        } else {
1079
            fat_cluster_t lastc;
1080
            (void) fat_cluster_walk(bs, dev_handle, nodep->firstc,
1081
                &lastc, (size - 1) / bpc);
1082
            fat_chop_clusters(bs, nodep, lastc);
1083
        }
1084
        nodep->size = size;
1085
        nodep->dirty = true;        /* need to sync node */
1086
        rc = EOK;  
3561 svoboda 1087
    }
1088
    fat_node_put(nodep);
1089
    ipc_answer_0(rid, rc);
1090
    return;
1091
}
1092
 
3674 svoboda 1093
void fat_destroy(ipc_callid_t rid, ipc_call_t *request)
1094
{
1095
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
1096
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
1097
    int rc;
1098
 
1099
    fat_node_t *nodep = fat_node_get(dev_handle, index);
1100
    if (!nodep) {
1101
        ipc_answer_0(rid, ENOENT);
1102
        return;
1103
    }
1104
 
1105
    rc = fat_destroy_node(nodep);
1106
    ipc_answer_0(rid, rc);
1107
}
1108
 
2627 jermar 1109
/**
1110
 * @}
1111
 */