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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"
2638 jermar 39
#include "../../vfs/vfs.h"
2793 jermar 40
#include <libfs.h>
2627 jermar 41
#include <ipc/ipc.h>
3257 jermar 42
#include <ipc/services.h>
43
#include <ipc/devmap.h>
2627 jermar 44
#include <async.h>
45
#include <errno.h>
2793 jermar 46
#include <string.h>
2798 jermar 47
#include <byteorder.h>
2831 jermar 48
#include <libadt/hash_table.h>
49
#include <libadt/list.h>
50
#include <assert.h>
2856 jermar 51
#include <futex.h>
3257 jermar 52
#include <sys/mman.h>
2627 jermar 53
 
2843 jermar 54
#define BS_BLOCK        0
3253 jermar 55
#define BS_SIZE         512
2843 jermar 56
 
2951 jermar 57
/** Futex protecting the list of cached free FAT nodes. */
58
static futex_t ffn_futex = FUTEX_INITIALIZER;
2843 jermar 59
 
2951 jermar 60
/** List of cached free FAT nodes. */
61
static LIST_INITIALIZE(ffn_head);
62
 
2638 jermar 63
#define FAT_NAME_LEN        8
64
#define FAT_EXT_LEN     3
65
 
66
#define FAT_PAD         ' ' 
67
 
68
#define FAT_DENTRY_UNUSED   0x00
69
#define FAT_DENTRY_E5_ESC   0x05
70
#define FAT_DENTRY_DOT      0x2e
71
#define FAT_DENTRY_ERASED   0xe5
72
 
3308 jermar 73
#define min(a, b)       ((a) < (b) ? (a) : (b))
74
 
2793 jermar 75
static void dentry_name_canonify(fat_dentry_t *d, char *buf)
2638 jermar 76
{
2793 jermar 77
    int i;
2639 jermar 78
 
2793 jermar 79
    for (i = 0; i < FAT_NAME_LEN; i++) {
3272 jermar 80
        if (d->name[i] == FAT_PAD)
2793 jermar 81
            break;
82
        if (d->name[i] == FAT_DENTRY_E5_ESC)
83
            *buf++ = 0xe5;
84
        else
85
            *buf++ = d->name[i];
86
    }
87
    if (d->ext[0] != FAT_PAD)
88
        *buf++ = '.';
89
    for (i = 0; i < FAT_EXT_LEN; i++) {
90
        if (d->ext[i] == FAT_PAD) {
91
            *buf = '\0';
92
            return;
93
        }
94
        if (d->ext[i] == FAT_DENTRY_E5_ESC)
95
            *buf++ = 0xe5;
96
        else
97
            *buf++ = d->ext[i];
98
    }
3272 jermar 99
    *buf = '\0';
2793 jermar 100
}
101
 
3257 jermar 102
static int dev_phone = -1;      /* FIXME */
103
static void *dev_buffer = NULL;     /* FIXME */
104
 
2910 jermar 105
/* TODO move somewhere else */
2822 jermar 106
typedef struct {
107
    void *data;
3257 jermar 108
    size_t size;
2822 jermar 109
} block_t;
110
 
3253 jermar 111
static block_t *block_get(dev_handle_t dev_handle, off_t offset, size_t bs)
2793 jermar 112
{
3257 jermar 113
    /* FIXME */
114
    block_t *b;
115
    off_t bufpos = 0;
116
    size_t buflen = 0;
3272 jermar 117
    off_t pos = offset * bs;
3257 jermar 118
 
119
    assert(dev_phone != -1);
120
    assert(dev_buffer);
121
 
122
    b = malloc(sizeof(block_t));
123
    if (!b)
124
        return NULL;
125
 
126
    b->data = malloc(bs);
127
    if (!b->data) {
128
        free(b);
129
        return NULL;
130
    }
131
    b->size = bs;
132
 
3272 jermar 133
    if (!libfs_blockread(dev_phone, dev_buffer, &bufpos, &buflen, &pos,
3257 jermar 134
        b->data, bs, bs)) {
135
        free(b->data);
136
        free(b);
137
        return NULL;
138
    }
139
 
140
    return b;
2793 jermar 141
}
142
 
2822 jermar 143
static void block_put(block_t *block)
2793 jermar 144
{
3257 jermar 145
    /* FIXME */
146
    free(block->data);
147
    free(block);
2793 jermar 148
}
149
 
2859 jermar 150
#define FAT_BS(b)       ((fat_bs_t *)((b)->data))
151
 
2864 jermar 152
#define FAT_CLST_RES0   0x0000
3119 jermar 153
#define FAT_CLST_RES1   0x0001
2859 jermar 154
#define FAT_CLST_FIRST  0x0002
155
#define FAT_CLST_BAD    0xfff7
156
#define FAT_CLST_LAST1  0xfff8
157
#define FAT_CLST_LAST8  0xffff
158
 
3119 jermar 159
/* internally used to mark root directory's parent */
160
#define FAT_CLST_ROOTPAR    FAT_CLST_RES0
161
/* internally used to mark root directory */
162
#define FAT_CLST_ROOT       FAT_CLST_RES1
163
 
2891 jermar 164
#define fat_block_get(np, off) \
165
    _fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))
166
 
167
static block_t *
2893 jermar 168
_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)
2859 jermar 169
{
170
    block_t *bb;
171
    block_t *b;
172
    unsigned bps;
173
    unsigned spc;
174
    unsigned rscnt;     /* block address of the first FAT */
175
    unsigned fatcnt;
176
    unsigned rde;
177
    unsigned rds;       /* root directory size */
178
    unsigned sf;
179
    unsigned ssa;       /* size of the system area */
180
    unsigned clusters;
2893 jermar 181
    fat_cluster_t clst = firstc;
2859 jermar 182
    unsigned i;
183
 
3253 jermar 184
    bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);
2859 jermar 185
    bps = uint16_t_le2host(FAT_BS(bb)->bps);
186
    spc = FAT_BS(bb)->spc;
187
    rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
188
    fatcnt = FAT_BS(bb)->fatcnt;
189
    rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
190
    sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);
191
    block_put(bb);
192
 
193
    rds = (sizeof(fat_dentry_t) * rde) / bps;
194
    rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
195
    ssa = rscnt + fatcnt * sf + rds;
196
 
3119 jermar 197
    if (firstc == FAT_CLST_ROOT) {
2859 jermar 198
        /* root directory special case */
199
        assert(offset < rds);
3253 jermar 200
        b = block_get(dev_handle, rscnt + fatcnt * sf + offset, bps);
2859 jermar 201
        return b;
202
    }
203
 
204
    clusters = offset / spc;
205
    for (i = 0; i < clusters; i++) {
206
        unsigned fsec;  /* sector offset relative to FAT1 */
207
        unsigned fidx;  /* FAT1 entry index */
208
 
209
        assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
2864 jermar 210
        fsec = (clst * sizeof(fat_cluster_t)) / bps;
211
        fidx = clst % (bps / sizeof(fat_cluster_t));
2859 jermar 212
        /* read FAT1 */
3253 jermar 213
        b = block_get(dev_handle, rscnt + fsec, bps);
2864 jermar 214
        clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
2859 jermar 215
        assert(clst != FAT_CLST_BAD);
216
        assert(clst < FAT_CLST_LAST1);
217
        block_put(b);
218
    }
219
 
2891 jermar 220
    b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
3253 jermar 221
        offset % spc, bps);
2859 jermar 222
 
223
    return b;
224
}
225
 
3325 jermar 226
/** Return number of blocks allocated to a file.
227
 *
228
 * @param dev_handle    Device handle of the device with the file.
229
 * @param firstc    First cluster of the file.
230
 *
231
 * @return      Number of blocks allocated to the file.
232
 */
233
static uint16_t
234
_fat_blcks_get(dev_handle_t dev_handle, fat_cluster_t firstc)
235
{
236
    block_t *bb;
237
    block_t *b;
238
    unsigned bps;
239
    unsigned spc;
240
    unsigned rscnt;     /* block address of the first FAT */
241
    unsigned clusters = 0;
242
    fat_cluster_t clst = firstc;
243
 
244
    bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);
245
    bps = uint16_t_le2host(FAT_BS(bb)->bps);
246
    spc = FAT_BS(bb)->spc;
247
    rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
248
    block_put(bb);
249
 
250
    if (firstc == FAT_CLST_RES0) {
251
        /* No space allocated to the file. */
252
        return 0;
253
    }
254
 
255
    while (clst < FAT_CLST_LAST1) {
256
        unsigned fsec;  /* sector offset relative to FAT1 */
257
        unsigned fidx;  /* FAT1 entry index */
258
 
259
        assert(clst >= FAT_CLST_FIRST);
260
        fsec = (clst * sizeof(fat_cluster_t)) / bps;
261
        fidx = clst % (bps / sizeof(fat_cluster_t));
262
        /* read FAT1 */
263
        b = block_get(dev_handle, rscnt + fsec, bps);
264
        clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
265
        assert(clst != FAT_CLST_BAD);
266
        block_put(b);
267
        clusters++;
268
    }
269
 
270
    return clusters * spc;
271
}
272
 
2831 jermar 273
static void fat_node_initialize(fat_node_t *node)
2793 jermar 274
{
2951 jermar 275
    futex_initialize(&node->lock, 1);
2864 jermar 276
    node->idx = NULL;
2831 jermar 277
    node->type = 0;
278
    link_initialize(&node->ffn_link);
279
    node->size = 0;
280
    node->lnkcnt = 0;
281
    node->refcnt = 0;
282
    node->dirty = false;
2793 jermar 283
}
284
 
2843 jermar 285
static uint16_t fat_bps_get(dev_handle_t dev_handle)
286
{
287
    block_t *bb;
288
    uint16_t bps;
289
 
3253 jermar 290
    bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);
2843 jermar 291
    assert(bb != NULL);
2859 jermar 292
    bps = uint16_t_le2host(FAT_BS(bb)->bps);
2843 jermar 293
    block_put(bb);
294
 
295
    return bps;
296
}
297
 
2845 jermar 298
typedef enum {
299
    FAT_DENTRY_SKIP,
300
    FAT_DENTRY_LAST,
301
    FAT_DENTRY_VALID
302
} fat_dentry_clsf_t;
303
 
304
static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)
305
{
306
    if (d->attr & FAT_ATTR_VOLLABEL) {
307
        /* volume label entry */
308
        return FAT_DENTRY_SKIP;
309
    }
310
    if (d->name[0] == FAT_DENTRY_ERASED) {
311
        /* not-currently-used entry */
312
        return FAT_DENTRY_SKIP;
313
    }
314
    if (d->name[0] == FAT_DENTRY_UNUSED) {
315
        /* never used entry */
316
        return FAT_DENTRY_LAST;
317
    }
318
    if (d->name[0] == FAT_DENTRY_DOT) {
319
        /*
320
         * Most likely '.' or '..'.
321
         * It cannot occur in a regular file name.
322
         */
323
        return FAT_DENTRY_SKIP;
324
    }
325
    return FAT_DENTRY_VALID;
326
}
327
 
2893 jermar 328
static void fat_node_sync(fat_node_t *node)
2831 jermar 329
{
330
    /* TODO */
331
}
332
 
2951 jermar 333
/** Internal version of fat_node_get().
334
 *
335
 * @param idxp      Locked index structure.
336
 */
337
static void *fat_node_get_core(fat_idx_t *idxp)
2831 jermar 338
{
2891 jermar 339
    block_t *b;
340
    fat_dentry_t *d;
3312 jermar 341
    fat_node_t *nodep = NULL;
2891 jermar 342
    unsigned bps;
343
    unsigned dps;
344
 
2951 jermar 345
    if (idxp->nodep) {
2891 jermar 346
        /*
347
         * We are lucky.
348
         * The node is already instantiated in memory.
349
         */
2951 jermar 350
        futex_down(&idxp->nodep->lock);
351
        if (!idxp->nodep->refcnt++)
3312 jermar 352
            list_remove(&idxp->nodep->ffn_link);
2951 jermar 353
        futex_up(&idxp->nodep->lock);
354
        return idxp->nodep;
2891 jermar 355
    }
356
 
357
    /*
358
     * We must instantiate the node from the file system.
359
     */
360
 
2951 jermar 361
    assert(idxp->pfc);
2891 jermar 362
 
2951 jermar 363
    futex_down(&ffn_futex);
2893 jermar 364
    if (!list_empty(&ffn_head)) {
2951 jermar 365
        /* Try to use a cached free node structure. */
366
        fat_idx_t *idxp_tmp;
2893 jermar 367
        nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
2951 jermar 368
        if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
369
            goto skip_cache;
370
        idxp_tmp = nodep->idx;
371
        if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
372
            futex_up(&nodep->lock);
373
            goto skip_cache;
374
        }
375
        list_remove(&nodep->ffn_link);
376
        futex_up(&ffn_futex);
2893 jermar 377
        if (nodep->dirty)
378
            fat_node_sync(nodep);
2951 jermar 379
        idxp_tmp->nodep = NULL;
380
        futex_up(&nodep->lock);
381
        futex_up(&idxp_tmp->lock);
2893 jermar 382
    } else {
2951 jermar 383
skip_cache:
2893 jermar 384
        /* Try to allocate a new node structure. */
2951 jermar 385
        futex_up(&ffn_futex);
2893 jermar 386
        nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
387
        if (!nodep)
388
            return NULL;
389
    }
2891 jermar 390
    fat_node_initialize(nodep);
391
 
2951 jermar 392
    bps = fat_bps_get(idxp->dev_handle);
2891 jermar 393
    dps = bps / sizeof(fat_dentry_t);
394
 
2893 jermar 395
    /* Read the block that contains the dentry of interest. */
2951 jermar 396
    b = _fat_block_get(idxp->dev_handle, idxp->pfc,
397
        (idxp->pdi * sizeof(fat_dentry_t)) / bps);
2891 jermar 398
    assert(b);
399
 
2951 jermar 400
    d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
2893 jermar 401
    if (d->attr & FAT_ATTR_SUBDIR) {
402
        /*
403
         * The only directory which does not have this bit set is the
404
         * root directory itself. The root directory node is handled
405
         * and initialized elsewhere.
406
         */
407
        nodep->type = FAT_DIRECTORY;
3282 jermar 408
        /*
3325 jermar 409
         * Unfortunately, the 'size' field of the FAT dentry is not
410
         * defined for the directory entry type. We must determine the
411
         * size of the directory by walking the FAT.
3282 jermar 412
         */
3325 jermar 413
        nodep->size = bps * _fat_blcks_get(idxp->dev_handle,
414
            uint16_t_le2host(d->firstc));
2893 jermar 415
    } else {
416
        nodep->type = FAT_FILE;
3282 jermar 417
        nodep->size = uint32_t_le2host(d->size);
2893 jermar 418
    }
419
    nodep->firstc = uint16_t_le2host(d->firstc);
420
    nodep->lnkcnt = 1;
421
    nodep->refcnt = 1;
422
 
423
    block_put(b);
424
 
425
    /* Link the idx structure with the node structure. */
2951 jermar 426
    nodep->idx = idxp;
427
    idxp->nodep = nodep;
2893 jermar 428
 
429
    return nodep;
2831 jermar 430
}
431
 
2951 jermar 432
/** Instantiate a FAT in-core node. */
433
static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
434
{
435
    void *node;
436
    fat_idx_t *idxp;
437
 
438
    idxp = fat_idx_get_by_index(dev_handle, index);
439
    if (!idxp)
440
        return NULL;
441
    /* idxp->lock held */
442
    node = fat_node_get_core(idxp);
443
    futex_up(&idxp->lock);
444
    return node;
445
}
446
 
2852 jermar 447
static void fat_node_put(void *node)
448
{
2910 jermar 449
    fat_node_t *nodep = (fat_node_t *)node;
450
 
2951 jermar 451
    futex_down(&nodep->lock);
2910 jermar 452
    if (!--nodep->refcnt) {
2951 jermar 453
        futex_down(&ffn_futex);
2910 jermar 454
        list_append(&nodep->ffn_link, &ffn_head);
2951 jermar 455
        futex_up(&ffn_futex);
2910 jermar 456
    }
2951 jermar 457
    futex_up(&nodep->lock);
2852 jermar 458
}
459
 
2857 jermar 460
static void *fat_create(int flags)
461
{
462
    return NULL;    /* not supported at the moment */
463
}
464
 
2858 jermar 465
static int fat_destroy(void *node)
2857 jermar 466
{
2858 jermar 467
    return ENOTSUP; /* not supported at the moment */
2857 jermar 468
}
469
 
470
static bool fat_link(void *prnt, void *chld, const char *name)
471
{
472
    return false;   /* not supported at the moment */
473
}
474
 
475
static int fat_unlink(void *prnt, void *chld)
476
{
477
    return ENOTSUP; /* not supported at the moment */
478
}
479
 
2793 jermar 480
static void *fat_match(void *prnt, const char *component)
481
{
482
    fat_node_t *parentp = (fat_node_t *)prnt;
483
    char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
2822 jermar 484
    unsigned i, j;
2828 jermar 485
    unsigned bps;       /* bytes per sector */
2822 jermar 486
    unsigned dps;       /* dentries per sector */
487
    unsigned blocks;
2793 jermar 488
    fat_dentry_t *d;
2822 jermar 489
    block_t *b;
2793 jermar 490
 
2953 jermar 491
    futex_down(&parentp->idx->lock);
2864 jermar 492
    bps = fat_bps_get(parentp->idx->dev_handle);
2828 jermar 493
    dps = bps / sizeof(fat_dentry_t);
494
    blocks = parentp->size / bps + (parentp->size % bps != 0);
2822 jermar 495
    for (i = 0; i < blocks; i++) {
496
        unsigned dentries;
2793 jermar 497
 
2864 jermar 498
        b = fat_block_get(parentp, i);
2822 jermar 499
        dentries = (i == blocks - 1) ?
500
            parentp->size % sizeof(fat_dentry_t) :
501
            dps;
502
        for (j = 0; j < dentries; j++) {
503
            d = ((fat_dentry_t *)b->data) + j;
2845 jermar 504
            switch (fat_classify_dentry(d)) {
505
            case FAT_DENTRY_SKIP:
2822 jermar 506
                continue;
2845 jermar 507
            case FAT_DENTRY_LAST:
2822 jermar 508
                block_put(b);
2953 jermar 509
                futex_up(&parentp->idx->lock);
2822 jermar 510
                return NULL;
2845 jermar 511
            default:
512
            case FAT_DENTRY_VALID:
513
                dentry_name_canonify(d, name);
514
                break;
2822 jermar 515
            }
3272 jermar 516
            if (stricmp(name, component) == 0) {
2822 jermar 517
                /* hit */
2951 jermar 518
                void *node;
2953 jermar 519
                /*
520
                 * Assume tree hierarchy for locking.  We
521
                 * already have the parent and now we are going
522
                 * to lock the child.  Never lock in the oposite
523
                 * order.
524
                 */
2890 jermar 525
                fat_idx_t *idx = fat_idx_get_by_pos(
2881 jermar 526
                    parentp->idx->dev_handle, parentp->firstc,
2864 jermar 527
                    i * dps + j);
2953 jermar 528
                futex_up(&parentp->idx->lock);
2890 jermar 529
                if (!idx) {
530
                    /*
531
                     * Can happen if memory is low or if we
532
                     * run out of 32-bit indices.
533
                     */
534
                    block_put(b);
535
                    return NULL;
536
                }
2951 jermar 537
                node = fat_node_get_core(idx);
538
                futex_up(&idx->lock);
2822 jermar 539
                block_put(b);
540
                return node;
541
            }
2793 jermar 542
        }
2822 jermar 543
        block_put(b);
2639 jermar 544
    }
2953 jermar 545
    futex_up(&parentp->idx->lock);
2793 jermar 546
    return NULL;
2638 jermar 547
}
548
 
2831 jermar 549
static fs_index_t fat_index_get(void *node)
550
{
551
    fat_node_t *fnodep = (fat_node_t *)node;
552
    if (!fnodep)
553
        return 0;
2864 jermar 554
    return fnodep->idx->index;
2831 jermar 555
}
556
 
557
static size_t fat_size_get(void *node)
558
{
559
    return ((fat_node_t *)node)->size;
560
}
561
 
562
static unsigned fat_lnkcnt_get(void *node)
563
{
564
    return ((fat_node_t *)node)->lnkcnt;
565
}
566
 
2845 jermar 567
static bool fat_has_children(void *node)
568
{
569
    fat_node_t *nodep = (fat_node_t *)node;
570
    unsigned bps;
571
    unsigned dps;
572
    unsigned blocks;
573
    block_t *b;
574
    unsigned i, j;
575
 
576
    if (nodep->type != FAT_DIRECTORY)
577
        return false;
578
 
2951 jermar 579
    futex_down(&nodep->idx->lock);
2864 jermar 580
    bps = fat_bps_get(nodep->idx->dev_handle);
2845 jermar 581
    dps = bps / sizeof(fat_dentry_t);
582
 
583
    blocks = nodep->size / bps + (nodep->size % bps != 0);
584
 
585
    for (i = 0; i < blocks; i++) {
586
        unsigned dentries;
587
        fat_dentry_t *d;
588
 
2864 jermar 589
        b = fat_block_get(nodep, i);
2845 jermar 590
        dentries = (i == blocks - 1) ?
591
            nodep->size % sizeof(fat_dentry_t) :
592
            dps;
593
        for (j = 0; j < dentries; j++) {
594
            d = ((fat_dentry_t *)b->data) + j;
595
            switch (fat_classify_dentry(d)) {
596
            case FAT_DENTRY_SKIP:
597
                continue;
598
            case FAT_DENTRY_LAST:
599
                block_put(b);
2951 jermar 600
                futex_up(&nodep->idx->lock);
2845 jermar 601
                return false;
602
            default:
603
            case FAT_DENTRY_VALID:
604
                block_put(b);
2951 jermar 605
                futex_up(&nodep->idx->lock);
2845 jermar 606
                return true;
607
            }
608
            block_put(b);
2951 jermar 609
            futex_up(&nodep->idx->lock);
2845 jermar 610
            return true;
611
        }
612
        block_put(b);
613
    }
614
 
2951 jermar 615
    futex_up(&nodep->idx->lock);
2845 jermar 616
    return false;
617
}
618
 
2844 jermar 619
static void *fat_root_get(dev_handle_t dev_handle)
620
{
3119 jermar 621
    return fat_node_get(dev_handle, 0);
2844 jermar 622
}
623
 
624
static char fat_plb_get_char(unsigned pos)
625
{
626
    return fat_reg.plb_ro[pos % PLB_SIZE];
627
}
628
 
2831 jermar 629
static bool fat_is_directory(void *node)
630
{
631
    return ((fat_node_t *)node)->type == FAT_DIRECTORY;
632
}
633
 
634
static bool fat_is_file(void *node)
635
{
636
    return ((fat_node_t *)node)->type == FAT_FILE;
637
}
638
 
2793 jermar 639
/** libfs operations */
640
libfs_ops_t fat_libfs_ops = {
641
    .match = fat_match,
642
    .node_get = fat_node_get,
2852 jermar 643
    .node_put = fat_node_put,
2857 jermar 644
    .create = fat_create,
645
    .destroy = fat_destroy,
646
    .link = fat_link,
647
    .unlink = fat_unlink,
2831 jermar 648
    .index_get = fat_index_get,
649
    .size_get = fat_size_get,
650
    .lnkcnt_get = fat_lnkcnt_get,
2845 jermar 651
    .has_children = fat_has_children,
2844 jermar 652
    .root_get = fat_root_get,
653
    .plb_get_char = fat_plb_get_char,
2831 jermar 654
    .is_directory = fat_is_directory,
655
    .is_file = fat_is_file
2793 jermar 656
};
657
 
3110 jermar 658
void fat_mounted(ipc_callid_t rid, ipc_call_t *request)
659
{
660
    dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
3119 jermar 661
    block_t *bb;
3257 jermar 662
    uint16_t bps;
3119 jermar 663
    uint16_t rde;
3110 jermar 664
    int rc;
665
 
3257 jermar 666
    /*
667
     * For now, we don't bother to remember dev_handle, dev_phone or
668
     * dev_buffer in some data structure. We use global variables because we
669
     * know there will be at most one mount on this file system.
670
     * Of course, this is a huge TODO item.
671
     */
672
    dev_buffer = mmap(NULL, BS_SIZE, PROTO_READ | PROTO_WRITE,
673
        MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
674
 
675
    if (!dev_buffer) {
676
        ipc_answer_0(rid, ENOMEM);
677
        return;
678
    }
679
 
680
    dev_phone = ipc_connect_me_to(PHONE_NS, SERVICE_DEVMAP,
681
        DEVMAP_CONNECT_TO_DEVICE, dev_handle);
682
 
683
    if (dev_phone < 0) {
684
        munmap(dev_buffer, BS_SIZE);
685
        ipc_answer_0(rid, dev_phone);
686
        return;
687
    }
688
 
689
    rc = ipc_share_out_start(dev_phone, dev_buffer,
690
        AS_AREA_READ | AS_AREA_WRITE);
691
    if (rc != EOK) {
692
            munmap(dev_buffer, BS_SIZE);
693
        ipc_answer_0(rid, rc);
694
        return;
695
    }
696
 
3119 jermar 697
    /* Read the number of root directory entries. */
3253 jermar 698
    bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);
3257 jermar 699
    bps = uint16_t_le2host(FAT_BS(bb)->bps);
3119 jermar 700
    rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
701
    block_put(bb);
702
 
3257 jermar 703
    if (bps != BS_SIZE) {
704
        munmap(dev_buffer, BS_SIZE);
705
        ipc_answer_0(rid, ENOTSUP);
706
        return;
707
    }
708
 
3110 jermar 709
    rc = fat_idx_init_by_dev_handle(dev_handle);
710
    if (rc != EOK) {
3257 jermar 711
            munmap(dev_buffer, BS_SIZE);
3110 jermar 712
        ipc_answer_0(rid, rc);
713
        return;
714
    }
715
 
3119 jermar 716
    /* Initialize the root node. */
717
    fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t));
718
    if (!rootp) {
3257 jermar 719
            munmap(dev_buffer, BS_SIZE);
3119 jermar 720
        fat_idx_fini_by_dev_handle(dev_handle);
721
        ipc_answer_0(rid, ENOMEM);
722
        return;
723
    }
724
    fat_node_initialize(rootp);
725
 
726
    fat_idx_t *ridxp = fat_idx_get_by_pos(dev_handle, FAT_CLST_ROOTPAR, 0);
727
    if (!ridxp) {
3257 jermar 728
            munmap(dev_buffer, BS_SIZE);
3119 jermar 729
        free(rootp);
730
        fat_idx_fini_by_dev_handle(dev_handle);
731
        ipc_answer_0(rid, ENOMEM);
732
        return;
733
    }
734
    assert(ridxp->index == 0);
735
    /* ridxp->lock held */
736
 
737
    rootp->type = FAT_DIRECTORY;
738
    rootp->firstc = FAT_CLST_ROOT;
739
    rootp->refcnt = 1;
3352 jermar 740
    rootp->lnkcnt = 0;  /* FS root is not linked */
3119 jermar 741
    rootp->size = rde * sizeof(fat_dentry_t);
742
    rootp->idx = ridxp;
743
    ridxp->nodep = rootp;
744
 
745
    futex_up(&ridxp->lock);
746
 
3352 jermar 747
    ipc_answer_3(rid, EOK, ridxp->index, rootp->size, rootp->lnkcnt);
3110 jermar 748
}
749
 
750
void fat_mount(ipc_callid_t rid, ipc_call_t *request)
751
{
752
    ipc_answer_0(rid, ENOTSUP);
753
}
754
 
2627 jermar 755
void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
756
{
2793 jermar 757
    libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
2627 jermar 758
}
759
 
3307 jermar 760
void fat_read(ipc_callid_t rid, ipc_call_t *request)
761
{
762
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
763
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
764
    off_t pos = (off_t)IPC_GET_ARG3(*request);
765
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
3308 jermar 766
    uint16_t bps = fat_bps_get(dev_handle);
767
    size_t bytes;
3335 jermar 768
    block_t *b;
3308 jermar 769
 
3307 jermar 770
    if (!nodep) {
771
        ipc_answer_0(rid, ENOENT);
772
        return;
773
    }
774
 
775
    ipc_callid_t callid;
776
    size_t len;
3314 jermar 777
    if (!ipc_data_read_receive(&callid, &len)) {
3307 jermar 778
        fat_node_put(nodep);
779
        ipc_answer_0(callid, EINVAL);
780
        ipc_answer_0(rid, EINVAL);
781
        return;
782
    }
783
 
784
    if (nodep->type == FAT_FILE) {
3335 jermar 785
        /*
786
         * Our strategy for regular file reads is to read one block at
787
         * most and make use of the possibility to return less data than
788
         * requested. This keeps the code very simple.
789
         */
3308 jermar 790
        bytes = min(len, bps - pos % bps);
791
        b = fat_block_get(nodep, pos / bps);
792
        (void) ipc_data_read_finalize(callid, b->data + pos % bps,
793
            bytes);
794
        block_put(b);
3307 jermar 795
    } else {
3335 jermar 796
        unsigned bnum;
797
        off_t spos = pos;
798
        char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
799
        fat_dentry_t *d;
800
 
3307 jermar 801
        assert(nodep->type == FAT_DIRECTORY);
3335 jermar 802
        assert(nodep->size % bps == 0);
803
        assert(bps % sizeof(fat_dentry_t) == 0);
804
 
805
        /*
806
         * Our strategy for readdir() is to use the position pointer as
807
         * an index into the array of all dentries. On entry, it points
808
         * to the first unread dentry. If we skip any dentries, we bump
809
         * the position pointer accordingly.
810
         */
811
        bnum = (pos * sizeof(fat_dentry_t)) / bps;
812
        while (bnum < nodep->size / bps) {
813
            off_t o;
814
 
815
            b = fat_block_get(nodep, bnum);
816
            for (o = pos % (bps / sizeof(fat_dentry_t));
817
                o < bps / sizeof(fat_dentry_t);
818
                o++, pos++) {
819
                d = ((fat_dentry_t *)b->data) + o;
820
                switch (fat_classify_dentry(d)) {
821
                case FAT_DENTRY_SKIP:
822
                    continue;
823
                case FAT_DENTRY_LAST:
824
                    block_put(b);
825
                    goto miss;
826
                default:
827
                case FAT_DENTRY_VALID:
828
                    dentry_name_canonify(d, name);
829
                    block_put(b);
830
                    goto hit;
831
                }
832
            }
833
            block_put(b);
834
            bnum++;
835
        }
836
miss:
3307 jermar 837
        fat_node_put(nodep);
3335 jermar 838
        ipc_answer_0(callid, ENOENT);
839
        ipc_answer_1(rid, ENOENT, 0);
3307 jermar 840
        return;
3335 jermar 841
hit:
842
        (void) ipc_data_read_finalize(callid, name, strlen(name) + 1);
843
        bytes = (pos - spos) + 1;
3307 jermar 844
    }
845
 
846
    fat_node_put(nodep);
3308 jermar 847
    ipc_answer_1(rid, EOK, (ipcarg_t)bytes);
3307 jermar 848
}
849
 
2627 jermar 850
/**
851
 * @}
852
 */