WebSVN – HelenOS – Diff – /trunk/uspace/srv/fs/fat/fat_ops.c


/*
 * Copyright (c) 2008 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
/** @addtogroup fs
 * @{
 */
 
/**
 * @file    fat_ops.c
 * @brief   Implementation of VFS operations for the FAT file system server.
 */
 
#include "fat.h"
#include "../../vfs/vfs.h"
#include <libfs.h>
#include <ipc/ipc.h>
#include <async.h>
#include <errno.h>
#include <string.h>
#include <byteorder.h>
#include <libadt/hash_table.h>
#include <libadt/list.h>
#include <assert.h>
#include <futex.h>
 
#define BS_BLOCK        0
 
/** List of free FAT nodes that still contain valid data. */
LIST_INITIALIZE(ffn_head);
 
#define FAT_NAME_LEN        8
#define FAT_EXT_LEN     3
 
#define FAT_PAD         ' ' 
 
#define FAT_DENTRY_UNUSED   0x00
#define FAT_DENTRY_E5_ESC   0x05
#define FAT_DENTRY_DOT      0x2e
#define FAT_DENTRY_ERASED   0xe5
 
static void dentry_name_canonify(fat_dentry_t *d, char *buf)
{
    int i;
 
    for (i = 0; i < FAT_NAME_LEN; i++) {
        if (d->name[i] == FAT_PAD) {
            buf++;
            break;
        }
        if (d->name[i] == FAT_DENTRY_E5_ESC)
            *buf++ = 0xe5;
        else
            *buf++ = d->name[i];
    }
    if (d->ext[0] != FAT_PAD)
        *buf++ = '.';
    for (i = 0; i < FAT_EXT_LEN; i++) {
        if (d->ext[i] == FAT_PAD) {
            *buf = '\0';
            return;
        }
        if (d->ext[i] == FAT_DENTRY_E5_ESC)
            *buf++ = 0xe5;
        else
            *buf++ = d->ext[i];
    }
}
 
/* TODO move somewhere else */
typedef struct {
    void *data;
} block_t;
 
static block_t *block_get(dev_handle_t dev_handle, off_t offset)
{
    return NULL;    /* TODO */
}
 
static void block_put(block_t *block)
{
    /* TODO */
}
 
#define FAT_BS(b)       ((fat_bs_t *)((b)->data))
 
#define FAT_CLST_RES0   0x0000
#define FAT_CLST_RES1   0x0001  /* internally used to mark root directory */
#define FAT_CLST_FIRST  0x0002
#define FAT_CLST_BAD    0xfff7
#define FAT_CLST_LAST1  0xfff8
#define FAT_CLST_LAST8  0xffff
 
#define fat_block_get(np, off) \
    _fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))
 
static block_t *
_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)
{
    block_t *bb;
    block_t *b;
    unsigned bps;
    unsigned spc;
    unsigned rscnt;     /* block address of the first FAT */
    unsigned fatcnt;
    unsigned rde;
    unsigned rds;       /* root directory size */
    unsigned sf;
    unsigned ssa;       /* size of the system area */
    unsigned clusters;
    fat_cluster_t clst = firstc;
    unsigned i;
 
    bb = block_get(dev_handle, BS_BLOCK);
    bps = uint16_t_le2host(FAT_BS(bb)->bps);
    spc = FAT_BS(bb)->spc;
    rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
    fatcnt = FAT_BS(bb)->fatcnt;
    rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
    sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);
    block_put(bb);
 
    rds = (sizeof(fat_dentry_t) * rde) / bps;
    rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
    ssa = rscnt + fatcnt * sf + rds;
 
    if (firstc == FAT_CLST_RES1) {
        /* root directory special case */
        assert(offset < rds);
        b = block_get(dev_handle, rscnt + fatcnt * sf + offset);
        return b;
    }
 
    clusters = offset / spc;
    for (i = 0; i < clusters; i++) {
        unsigned fsec;  /* sector offset relative to FAT1 */
        unsigned fidx;  /* FAT1 entry index */
 
        assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
        fsec = (clst * sizeof(fat_cluster_t)) / bps;
        fidx = clst % (bps / sizeof(fat_cluster_t));
        /* read FAT1 */
        b = block_get(dev_handle, rscnt + fsec);
        clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
        assert(clst != FAT_CLST_BAD);
        assert(clst < FAT_CLST_LAST1);
        block_put(b);
    }
 
    b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
        offset % spc);
 
    return b;
}
 
static void fat_node_initialize(fat_node_t *node)
{
    node->idx = NULL;
    node->type = 0;
    link_initialize(&node->ffn_link);
    node->size = 0;
    node->lnkcnt = 0;
    node->refcnt = 0;
    node->dirty = false;
}
 
static uint16_t fat_bps_get(dev_handle_t dev_handle)
{
    block_t *bb;
    uint16_t bps;
   
    bb = block_get(dev_handle, BS_BLOCK);
    assert(bb != NULL);
    bps = uint16_t_le2host(FAT_BS(bb)->bps);
    block_put(bb);
 
    return bps;
}
 
typedef enum {
    FAT_DENTRY_SKIP,
    FAT_DENTRY_LAST,
    FAT_DENTRY_VALID
} fat_dentry_clsf_t;
 
static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)
{
    if (d->attr & FAT_ATTR_VOLLABEL) {
        /* volume label entry */
        return FAT_DENTRY_SKIP;
    }
    if (d->name[0] == FAT_DENTRY_ERASED) {
        /* not-currently-used entry */
        return FAT_DENTRY_SKIP;
    }
    if (d->name[0] == FAT_DENTRY_UNUSED) {
        /* never used entry */
        return FAT_DENTRY_LAST;
    }
    if (d->name[0] == FAT_DENTRY_DOT) {
        /*
         * Most likely '.' or '..'.
         * It cannot occur in a regular file name.
         */
        return FAT_DENTRY_SKIP;
    }
    return FAT_DENTRY_VALID;
}
 
static void fat_node_sync(fat_node_t *node)
{
    /* TODO */
}
 
/** Instantiate a FAT in-core node. */
static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
{
    fat_idx_t *idx;
    block_t *b;
    fat_dentry_t *d;
    fat_node_t *nodep;
    unsigned bps;
    unsigned dps;
 
    idx = fat_idx_get_by_index(dev_handle, index);
    if (!idx)
        return NULL;
 
    if (idx->nodep) {
        /*
         * We are lucky.
         * The node is already instantiated in memory.
         */
        if (!idx->nodep->refcnt++)
            list_remove(&nodep->ffn_link);
        return idx->nodep;
    }
 
    /*
     * We must instantiate the node from the file system.
     */
   
    assert(idx->pfc);
 
    if (!list_empty(&ffn_head)) {
        /* Try to use a cached unused node structure. */
        nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
        if (nodep->dirty)
            fat_node_sync(nodep);
        list_remove(&nodep->ffn_link);
        nodep->idx->nodep = NULL;
    } else {
        /* Try to allocate a new node structure. */
        nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
        if (!nodep)
            return NULL;
    }
    fat_node_initialize(nodep);
 
    bps = fat_bps_get(dev_handle);
    dps = bps / sizeof(fat_dentry_t);
 
    /* Read the block that contains the dentry of interest. */
    b = _fat_block_get(dev_handle, idx->pfc,
        (idx->pdi * sizeof(fat_dentry_t)) / bps);
    assert(b);
 
    d = ((fat_dentry_t *)b->data) + (idx->pdi % dps);
    if (d->attr & FAT_ATTR_SUBDIR) {
        /*
         * The only directory which does not have this bit set is the
         * root directory itself. The root directory node is handled
         * and initialized elsewhere.
         */
        nodep->type = FAT_DIRECTORY;
    } else {
        nodep->type = FAT_FILE;
    }
    nodep->firstc = uint16_t_le2host(d->firstc);
    nodep->size = uint32_t_le2host(d->size);
    nodep->lnkcnt = 1;
    nodep->refcnt = 1;
 
    block_put(b);
 
    /* Link the idx structure with the node structure. */
    nodep->idx = idx;
    idx->nodep = nodep;
 
    return nodep;
}
 
static void fat_node_put(void *node)
{
    fat_node_t *nodep = (fat_node_t *)node;
 
    if (!--nodep->refcnt) {
        list_append(&nodep->ffn_link, &ffn_head);
    }
}
 
static void *fat_create(int flags)
{
    return NULL;    /* not supported at the moment */
}
 
static int fat_destroy(void *node)
{
    return ENOTSUP; /* not supported at the moment */
}
 
static bool fat_link(void *prnt, void *chld, const char *name)
{
    return false;   /* not supported at the moment */
}
 
static int fat_unlink(void *prnt, void *chld)
{
    return ENOTSUP; /* not supported at the moment */
}
 
static void *fat_match(void *prnt, const char *component)
{
    fat_node_t *parentp = (fat_node_t *)prnt;
    char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
    unsigned i, j;
    unsigned bps;       /* bytes per sector */
    unsigned dps;       /* dentries per sector */
    unsigned blocks;
    fat_dentry_t *d;
    block_t *b;
 
    bps = fat_bps_get(parentp->idx->dev_handle);
    dps = bps / sizeof(fat_dentry_t);
    blocks = parentp->size / bps + (parentp->size % bps != 0);
    for (i = 0; i < blocks; i++) {
        unsigned dentries;
       
        b = fat_block_get(parentp, i);
        dentries = (i == blocks - 1) ?
            parentp->size % sizeof(fat_dentry_t) :
            dps;
        for (j = 0; j < dentries; j++) {
            d = ((fat_dentry_t *)b->data) + j;
            switch (fat_classify_dentry(d)) {
            case FAT_DENTRY_SKIP:
                continue;
            case FAT_DENTRY_LAST:
                block_put(b);
                return NULL;
            default:
            case FAT_DENTRY_VALID:
                dentry_name_canonify(d, name);
                break;
            }
            if (strcmp(name, component) == 0) {
                /* hit */
                fat_idx_t *idx = fat_idx_get_by_pos(
                    parentp->idx->dev_handle, parentp->firstc,
                    i * dps + j);
                if (!idx) {
                    /*
                     * Can happen if memory is low or if we
                     * run out of 32-bit indices.
                     */
                    block_put(b);
                    return NULL;
                }
                void *node = fat_node_get(idx->dev_handle,
                    idx->index);
                block_put(b);
                return node;
            }
        }
        block_put(b);
    }
 
    return NULL;
}
 
static fs_index_t fat_index_get(void *node)
{
    fat_node_t *fnodep = (fat_node_t *)node;
    if (!fnodep)
        return 0;
    return fnodep->idx->index;
}
 
static size_t fat_size_get(void *node)
{
    return ((fat_node_t *)node)->size;
}
 
static unsigned fat_lnkcnt_get(void *node)
{
    return ((fat_node_t *)node)->lnkcnt;
}
 
static bool fat_has_children(void *node)
{
    fat_node_t *nodep = (fat_node_t *)node;
    unsigned bps;
    unsigned dps;
    unsigned blocks;
    block_t *b;
    unsigned i, j;
 
    if (nodep->type != FAT_DIRECTORY)
        return false;
 
    bps = fat_bps_get(nodep->idx->dev_handle);
    dps = bps / sizeof(fat_dentry_t);
 
    blocks = nodep->size / bps + (nodep->size % bps != 0);
 
    for (i = 0; i < blocks; i++) {
        unsigned dentries;
        fat_dentry_t *d;
   
        b = fat_block_get(nodep, i);
        dentries = (i == blocks - 1) ?
            nodep->size % sizeof(fat_dentry_t) :
            dps;
        for (j = 0; j < dentries; j++) {
            d = ((fat_dentry_t *)b->data) + j;
            switch (fat_classify_dentry(d)) {
            case FAT_DENTRY_SKIP:
                continue;
            case FAT_DENTRY_LAST:
                block_put(b);
                return false;
            default:
            case FAT_DENTRY_VALID:
                block_put(b);
                return true;
            }
            block_put(b);
            return true;
        }
        block_put(b);
    }
 
    return false;
}
 
static void *fat_root_get(dev_handle_t dev_handle)
{
    return NULL;    /* TODO */
}
 
static char fat_plb_get_char(unsigned pos)
{
    return fat_reg.plb_ro[pos % PLB_SIZE];
}
 
static bool fat_is_directory(void *node)
{
    return ((fat_node_t *)node)->type == FAT_DIRECTORY;
}
 
static bool fat_is_file(void *node)
{
    return ((fat_node_t *)node)->type == FAT_FILE;
}
 
/** libfs operations */
libfs_ops_t fat_libfs_ops = {
    .match = fat_match,
    .node_get = fat_node_get,
    .node_put = fat_node_put,
    .create = fat_create,
    .destroy = fat_destroy,
    .link = fat_link,
    .unlink = fat_unlink,
    .index_get = fat_index_get,
    .size_get = fat_size_get,
    .lnkcnt_get = fat_lnkcnt_get,
    .has_children = fat_has_children,
    .root_get = fat_root_get,
    .plb_get_char = fat_plb_get_char,
    .is_directory = fat_is_directory,
    .is_file = fat_is_file
};
 
void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
{
    libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
}
 
/**
 * @}
 */
 

Rev 2893	Rev 2910
1	/*	1	/*
2	* Copyright (c) 2008 Jakub Jermar	2	* Copyright (c) 2008 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	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	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.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	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	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	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	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	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	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.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/** @addtogroup fs	29	/** @addtogroup fs
30	* @{	30	* @{
31	*/	31	*/
32		32
33	/**	33	/**
34	* @file fat_ops.c	34	* @file fat_ops.c
35	* @brief Implementation of VFS operations for the FAT file system server.	35	* @brief Implementation of VFS operations for the FAT file system server.
36	*/	36	*/
37		37
38	#include "fat.h"	38	#include "fat.h"
39	#include "../../vfs/vfs.h"	39	#include "../../vfs/vfs.h"
40	#include <libfs.h>	40	#include <libfs.h>
41	#include <ipc/ipc.h>	41	#include <ipc/ipc.h>
42	#include <async.h>	42	#include <async.h>
43	#include <errno.h>	43	#include <errno.h>
44	#include <string.h>	44	#include <string.h>
45	#include <byteorder.h>	45	#include <byteorder.h>
46	#include <libadt/hash_table.h>	46	#include <libadt/hash_table.h>
47	#include <libadt/list.h>	47	#include <libadt/list.h>
48	#include <assert.h>	48	#include <assert.h>
49	#include <futex.h>	49	#include <futex.h>
50		50
51	#define BS_BLOCK 0	51	#define BS_BLOCK 0
52		52
53	/** List of free FAT nodes that still contain valid data. */	53	/** List of free FAT nodes that still contain valid data. */
54	LIST_INITIALIZE(ffn_head);	54	LIST_INITIALIZE(ffn_head);
55		55
56	#define FAT_NAME_LEN 8	56	#define FAT_NAME_LEN 8
57	#define FAT_EXT_LEN 3	57	#define FAT_EXT_LEN 3
58		58
59	#define FAT_PAD ' '	59	#define FAT_PAD ' '
60		60
61	#define FAT_DENTRY_UNUSED 0x00	61	#define FAT_DENTRY_UNUSED 0x00
62	#define FAT_DENTRY_E5_ESC 0x05	62	#define FAT_DENTRY_E5_ESC 0x05
63	#define FAT_DENTRY_DOT 0x2e	63	#define FAT_DENTRY_DOT 0x2e
64	#define FAT_DENTRY_ERASED 0xe5	64	#define FAT_DENTRY_ERASED 0xe5
65		65
66	static void dentry_name_canonify(fat_dentry_t d, char buf)	66	static void dentry_name_canonify(fat_dentry_t d, char buf)
67	{	67	{
68	int i;	68	int i;
69		69
70	for (i = 0; i < FAT_NAME_LEN; i++) {	70	for (i = 0; i < FAT_NAME_LEN; i++) {
71	if (d->name[i] == FAT_PAD) {	71	if (d->name[i] == FAT_PAD) {
72	buf++;	72	buf++;
73	break;	73	break;
74	}	74	}
75	if (d->name[i] == FAT_DENTRY_E5_ESC)	75	if (d->name[i] == FAT_DENTRY_E5_ESC)
76	*buf++ = 0xe5;	76	*buf++ = 0xe5;
77	else	77	else
78	*buf++ = d->name[i];	78	*buf++ = d->name[i];
79	}	79	}
80	if (d->ext[0] != FAT_PAD)	80	if (d->ext[0] != FAT_PAD)
81	*buf++ = '.';	81	*buf++ = '.';
82	for (i = 0; i < FAT_EXT_LEN; i++) {	82	for (i = 0; i < FAT_EXT_LEN; i++) {
83	if (d->ext[i] == FAT_PAD) {	83	if (d->ext[i] == FAT_PAD) {
84	*buf = '\0';	84	*buf = '\0';
85	return;	85	return;
86	}	86	}
87	if (d->ext[i] == FAT_DENTRY_E5_ESC)	87	if (d->ext[i] == FAT_DENTRY_E5_ESC)
88	*buf++ = 0xe5;	88	*buf++ = 0xe5;
89	else	89	else
90	*buf++ = d->ext[i];	90	*buf++ = d->ext[i];
91	}	91	}
92	}	92	}
93		93
94	/* TODO and also move somewhere else */	94	/* TODO move somewhere else */
95	typedef struct {	95	typedef struct {
96	void *data;	96	void *data;
97	} block_t;	97	} block_t;
98		98
99	static block_t *block_get(dev_handle_t dev_handle, off_t offset)	99	static block_t *block_get(dev_handle_t dev_handle, off_t offset)
100	{	100	{
101	return NULL; /* TODO */	101	return NULL; /* TODO */
102	}	102	}
103		103
104	static void block_put(block_t *block)	104	static void block_put(block_t *block)
105	{	105	{
106	/* TODO */	106	/* TODO */
107	}	107	}
108		108
109	#define FAT_BS(b) ((fat_bs_t *)((b)->data))	109	#define FAT_BS(b) ((fat_bs_t *)((b)->data))
110		110
111	#define FAT_CLST_RES0 0x0000	111	#define FAT_CLST_RES0 0x0000
112	#define FAT_CLST_RES1 0x0001 /* internally used to mark root directory */	112	#define FAT_CLST_RES1 0x0001 /* internally used to mark root directory */
113	#define FAT_CLST_FIRST 0x0002	113	#define FAT_CLST_FIRST 0x0002
114	#define FAT_CLST_BAD 0xfff7	114	#define FAT_CLST_BAD 0xfff7
115	#define FAT_CLST_LAST1 0xfff8	115	#define FAT_CLST_LAST1 0xfff8
116	#define FAT_CLST_LAST8 0xffff	116	#define FAT_CLST_LAST8 0xffff
117		117
118	#define fat_block_get(np, off) \	118	#define fat_block_get(np, off) \
119	_fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))	119	_fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))
120		120
121	static block_t *	121	static block_t *
122	_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)	122	_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)
123	{	123	{
124	block_t *bb;	124	block_t *bb;
125	block_t *b;	125	block_t *b;
126	unsigned bps;	126	unsigned bps;
127	unsigned spc;	127	unsigned spc;
128	unsigned rscnt; /* block address of the first FAT */	128	unsigned rscnt; /* block address of the first FAT */
129	unsigned fatcnt;	129	unsigned fatcnt;
130	unsigned rde;	130	unsigned rde;
131	unsigned rds; /* root directory size */	131	unsigned rds; /* root directory size */
132	unsigned sf;	132	unsigned sf;
133	unsigned ssa; /* size of the system area */	133	unsigned ssa; /* size of the system area */
134	unsigned clusters;	134	unsigned clusters;
135	fat_cluster_t clst = firstc;	135	fat_cluster_t clst = firstc;
136	unsigned i;	136	unsigned i;
137		137
138	bb = block_get(dev_handle, BS_BLOCK);	138	bb = block_get(dev_handle, BS_BLOCK);
139	bps = uint16_t_le2host(FAT_BS(bb)->bps);	139	bps = uint16_t_le2host(FAT_BS(bb)->bps);
140	spc = FAT_BS(bb)->spc;	140	spc = FAT_BS(bb)->spc;
141	rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);	141	rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
142	fatcnt = FAT_BS(bb)->fatcnt;	142	fatcnt = FAT_BS(bb)->fatcnt;
143	rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);	143	rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
144	sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);	144	sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);
145	block_put(bb);	145	block_put(bb);
146		146
147	rds = (sizeof(fat_dentry_t) * rde) / bps;	147	rds = (sizeof(fat_dentry_t) * rde) / bps;
148	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);	148	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
149	ssa = rscnt + fatcnt * sf + rds;	149	ssa = rscnt + fatcnt * sf + rds;
150		150
151	if (firstc == FAT_CLST_RES1) {	151	if (firstc == FAT_CLST_RES1) {
152	/* root directory special case */	152	/* root directory special case */
153	assert(offset < rds);	153	assert(offset < rds);
154	b = block_get(dev_handle, rscnt + fatcnt * sf + offset);	154	b = block_get(dev_handle, rscnt + fatcnt * sf + offset);
155	return b;	155	return b;
156	}	156	}
157		157
158	clusters = offset / spc;	158	clusters = offset / spc;
159	for (i = 0; i < clusters; i++) {	159	for (i = 0; i < clusters; i++) {
160	unsigned fsec; /* sector offset relative to FAT1 */	160	unsigned fsec; /* sector offset relative to FAT1 */
161	unsigned fidx; /* FAT1 entry index */	161	unsigned fidx; /* FAT1 entry index */
162		162
163	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);	163	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
164	fsec = (clst * sizeof(fat_cluster_t)) / bps;	164	fsec = (clst * sizeof(fat_cluster_t)) / bps;
165	fidx = clst % (bps / sizeof(fat_cluster_t));	165	fidx = clst % (bps / sizeof(fat_cluster_t));
166	/* read FAT1 */	166	/* read FAT1 */
167	b = block_get(dev_handle, rscnt + fsec);	167	b = block_get(dev_handle, rscnt + fsec);
168	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);	168	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
169	assert(clst != FAT_CLST_BAD);	169	assert(clst != FAT_CLST_BAD);
170	assert(clst < FAT_CLST_LAST1);	170	assert(clst < FAT_CLST_LAST1);
171	block_put(b);	171	block_put(b);
172	}	172	}
173		173
174	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +	174	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
175	offset % spc);	175	offset % spc);
176		176
177	return b;	177	return b;
178	}	178	}
179		179
180	static void fat_node_initialize(fat_node_t *node)	180	static void fat_node_initialize(fat_node_t *node)
181	{	181	{
182	node->idx = NULL;	182	node->idx = NULL;
183	node->type = 0;	183	node->type = 0;
184	link_initialize(&node->ffn_link);	184	link_initialize(&node->ffn_link);
185	node->size = 0;	185	node->size = 0;
186	node->lnkcnt = 0;	186	node->lnkcnt = 0;
187	node->refcnt = 0;	187	node->refcnt = 0;
188	node->dirty = false;	188	node->dirty = false;
189	}	189	}
190		190
191	static uint16_t fat_bps_get(dev_handle_t dev_handle)	191	static uint16_t fat_bps_get(dev_handle_t dev_handle)
192	{	192	{
193	block_t *bb;	193	block_t *bb;
194	uint16_t bps;	194	uint16_t bps;
195		195
196	bb = block_get(dev_handle, BS_BLOCK);	196	bb = block_get(dev_handle, BS_BLOCK);
197	assert(bb != NULL);	197	assert(bb != NULL);
198	bps = uint16_t_le2host(FAT_BS(bb)->bps);	198	bps = uint16_t_le2host(FAT_BS(bb)->bps);
199	block_put(bb);	199	block_put(bb);
200		200
201	return bps;	201	return bps;
202	}	202	}
203		203
204	typedef enum {	204	typedef enum {
205	FAT_DENTRY_SKIP,	205	FAT_DENTRY_SKIP,
206	FAT_DENTRY_LAST,	206	FAT_DENTRY_LAST,
207	FAT_DENTRY_VALID	207	FAT_DENTRY_VALID
208	} fat_dentry_clsf_t;	208	} fat_dentry_clsf_t;
209		209
210	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)	210	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)
211	{	211	{
212	if (d->attr & FAT_ATTR_VOLLABEL) {	212	if (d->attr & FAT_ATTR_VOLLABEL) {
213	/* volume label entry */	213	/* volume label entry */
214	return FAT_DENTRY_SKIP;	214	return FAT_DENTRY_SKIP;
215	}	215	}
216	if (d->name[0] == FAT_DENTRY_ERASED) {	216	if (d->name[0] == FAT_DENTRY_ERASED) {
217	/* not-currently-used entry */	217	/* not-currently-used entry */
218	return FAT_DENTRY_SKIP;	218	return FAT_DENTRY_SKIP;
219	}	219	}
220	if (d->name[0] == FAT_DENTRY_UNUSED) {	220	if (d->name[0] == FAT_DENTRY_UNUSED) {
221	/* never used entry */	221	/* never used entry */
222	return FAT_DENTRY_LAST;	222	return FAT_DENTRY_LAST;
223	}	223	}
224	if (d->name[0] == FAT_DENTRY_DOT) {	224	if (d->name[0] == FAT_DENTRY_DOT) {
225	/*	225	/*
226	* Most likely '.' or '..'.	226	* Most likely '.' or '..'.
227	* It cannot occur in a regular file name.	227	* It cannot occur in a regular file name.
228	*/	228	*/
229	return FAT_DENTRY_SKIP;	229	return FAT_DENTRY_SKIP;
230	}	230	}
231	return FAT_DENTRY_VALID;	231	return FAT_DENTRY_VALID;
232	}	232	}
233		233
234	static void fat_node_sync(fat_node_t *node)	234	static void fat_node_sync(fat_node_t *node)
235	{	235	{
236	/* TODO */	236	/* TODO */
237	}	237	}
238		238
239	/** Instantiate a FAT in-core node. */	239	/** Instantiate a FAT in-core node. */
240	static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)	240	static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
241	{	241	{
242	fat_idx_t *idx;	242	fat_idx_t *idx;
243	block_t *b;	243	block_t *b;
244	fat_dentry_t *d;	244	fat_dentry_t *d;
245	fat_node_t *nodep;	245	fat_node_t *nodep;
246	unsigned bps;	246	unsigned bps;
247	unsigned dps;	247	unsigned dps;
248		248
249	idx = fat_idx_get_by_index(dev_handle, index);	249	idx = fat_idx_get_by_index(dev_handle, index);
250	if (!idx)	250	if (!idx)
251	return NULL;	251	return NULL;
252		252
253	if (idx->nodep) {	253	if (idx->nodep) {
254	/*	254	/*
255	* We are lucky.	255	* We are lucky.
256	* The node is already instantiated in memory.	256	* The node is already instantiated in memory.
257	*/	257	*/
258	idx->nodep->refcnt++;	258	if (!idx->nodep->refcnt++)
-		259	list_remove(&nodep->ffn_link);
259	return idx->nodep;	260	return idx->nodep;
260	}	261	}
261		262
262	/*	263	/*
263	* We must instantiate the node from the file system.	264	* We must instantiate the node from the file system.
264	*/	265	*/
265		266
266	assert(idx->pfc);	267	assert(idx->pfc);
267		268
268	if (!list_empty(&ffn_head)) {	269	if (!list_empty(&ffn_head)) {
269	/* Try to use a cached unused node structure. */	270	/* Try to use a cached unused node structure. */
270	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);	271	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
271	if (nodep->dirty)	272	if (nodep->dirty)
272	fat_node_sync(nodep);	273	fat_node_sync(nodep);
273	list_remove(&nodep->ffn_link);	274	list_remove(&nodep->ffn_link);
274	nodep->idx->nodep = NULL;	275	nodep->idx->nodep = NULL;
275	} else {	276	} else {
276	/* Try to allocate a new node structure. */	277	/* Try to allocate a new node structure. */
277	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));	278	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
278	if (!nodep)	279	if (!nodep)
279	return NULL;	280	return NULL;
280	}	281	}
281	fat_node_initialize(nodep);	282	fat_node_initialize(nodep);
282		283
283	bps = fat_bps_get(dev_handle);	284	bps = fat_bps_get(dev_handle);
284	dps = bps / sizeof(fat_dentry_t);	285	dps = bps / sizeof(fat_dentry_t);
285		286
286	/* Read the block that contains the dentry of interest. */	287	/* Read the block that contains the dentry of interest. */
287	b = _fat_block_get(dev_handle, idx->pfc,	288	b = _fat_block_get(dev_handle, idx->pfc,
288	(idx->pdi * sizeof(fat_dentry_t)) / bps);	289	(idx->pdi * sizeof(fat_dentry_t)) / bps);
289	assert(b);	290	assert(b);
290		291
291	d = ((fat_dentry_t *)b->data) + (idx->pdi % dps);	292	d = ((fat_dentry_t *)b->data) + (idx->pdi % dps);
292	if (d->attr & FAT_ATTR_SUBDIR) {	293	if (d->attr & FAT_ATTR_SUBDIR) {
293	/*	294	/*
294	* The only directory which does not have this bit set is the	295	* The only directory which does not have this bit set is the
295	* root directory itself. The root directory node is handled	296	* root directory itself. The root directory node is handled
296	* and initialized elsewhere.	297	* and initialized elsewhere.
297	*/	298	*/
298	nodep->type = FAT_DIRECTORY;	299	nodep->type = FAT_DIRECTORY;
299	} else {	300	} else {
300	nodep->type = FAT_FILE;	301	nodep->type = FAT_FILE;
301	}	302	}
302	nodep->firstc = uint16_t_le2host(d->firstc);	303	nodep->firstc = uint16_t_le2host(d->firstc);
303	nodep->size = uint32_t_le2host(d->size);	304	nodep->size = uint32_t_le2host(d->size);
304	nodep->lnkcnt = 1;	305	nodep->lnkcnt = 1;
305	nodep->refcnt = 1;	306	nodep->refcnt = 1;
306		307
307	block_put(b);	308	block_put(b);
308		309
309	/* Link the idx structure with the node structure. */	310	/* Link the idx structure with the node structure. */
310	nodep->idx = idx;	311	nodep->idx = idx;
311	idx->nodep = nodep;	312	idx->nodep = nodep;
312		313
313	return nodep;	314	return nodep;
314	}	315	}
315		316
316	static void fat_node_put(void *node)	317	static void fat_node_put(void *node)
317	{	318	{
-		319	fat_node_t nodep = (fat_node_t )node;
-		320
318	/* TODO */	321	if (!--nodep->refcnt) {
-		322	list_append(&nodep->ffn_link, &ffn_head);
-		323	}
319	}	324	}
320		325
321	static void *fat_create(int flags)	326	static void *fat_create(int flags)
322	{	327	{
323	return NULL; /* not supported at the moment */	328	return NULL; /* not supported at the moment */
324	}	329	}
325		330
326	static int fat_destroy(void *node)	331	static int fat_destroy(void *node)
327	{	332	{
328	return ENOTSUP; /* not supported at the moment */	333	return ENOTSUP; /* not supported at the moment */
329	}	334	}
330		335
331	static bool fat_link(void prnt, void chld, const char *name)	336	static bool fat_link(void prnt, void chld, const char *name)
332	{	337	{
333	return false; /* not supported at the moment */	338	return false; /* not supported at the moment */
334	}	339	}
335		340
336	static int fat_unlink(void prnt, void chld)	341	static int fat_unlink(void prnt, void chld)
337	{	342	{
338	return ENOTSUP; /* not supported at the moment */	343	return ENOTSUP; /* not supported at the moment */
339	}	344	}
340		345
341	static void fat_match(void prnt, const char *component)	346	static void fat_match(void prnt, const char *component)
342	{	347	{
343	fat_node_t parentp = (fat_node_t )prnt;	348	fat_node_t parentp = (fat_node_t )prnt;
344	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];	349	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
345	unsigned i, j;	350	unsigned i, j;
346	unsigned bps; /* bytes per sector */	351	unsigned bps; /* bytes per sector */
347	unsigned dps; /* dentries per sector */	352	unsigned dps; /* dentries per sector */
348	unsigned blocks;	353	unsigned blocks;
349	fat_dentry_t *d;	354	fat_dentry_t *d;
350	block_t *b;	355	block_t *b;
351		356
352	bps = fat_bps_get(parentp->idx->dev_handle);	357	bps = fat_bps_get(parentp->idx->dev_handle);
353	dps = bps / sizeof(fat_dentry_t);	358	dps = bps / sizeof(fat_dentry_t);
354	blocks = parentp->size / bps + (parentp->size % bps != 0);	359	blocks = parentp->size / bps + (parentp->size % bps != 0);
355	for (i = 0; i < blocks; i++) {	360	for (i = 0; i < blocks; i++) {
356	unsigned dentries;	361	unsigned dentries;
357		362
358	b = fat_block_get(parentp, i);	363	b = fat_block_get(parentp, i);
359	dentries = (i == blocks - 1) ?	364	dentries = (i == blocks - 1) ?
360	parentp->size % sizeof(fat_dentry_t) :	365	parentp->size % sizeof(fat_dentry_t) :
361	dps;	366	dps;
362	for (j = 0; j < dentries; j++) {	367	for (j = 0; j < dentries; j++) {
363	d = ((fat_dentry_t *)b->data) + j;	368	d = ((fat_dentry_t *)b->data) + j;
364	switch (fat_classify_dentry(d)) {	369	switch (fat_classify_dentry(d)) {
365	case FAT_DENTRY_SKIP:	370	case FAT_DENTRY_SKIP:
366	continue;	371	continue;
367	case FAT_DENTRY_LAST:	372	case FAT_DENTRY_LAST:
368	block_put(b);	373	block_put(b);
369	return NULL;	374	return NULL;
370	default:	375	default:
371	case FAT_DENTRY_VALID:	376	case FAT_DENTRY_VALID:
372	dentry_name_canonify(d, name);	377	dentry_name_canonify(d, name);
373	break;	378	break;
374	}	379	}
375	if (strcmp(name, component) == 0) {	380	if (strcmp(name, component) == 0) {
376	/* hit */	381	/* hit */
377	fat_idx_t *idx = fat_idx_get_by_pos(	382	fat_idx_t *idx = fat_idx_get_by_pos(
378	parentp->idx->dev_handle, parentp->firstc,	383	parentp->idx->dev_handle, parentp->firstc,
379	i * dps + j);	384	i * dps + j);
380	if (!idx) {	385	if (!idx) {
381	/*	386	/*
382	* Can happen if memory is low or if we	387	* Can happen if memory is low or if we
383	* run out of 32-bit indices.	388	* run out of 32-bit indices.
384	*/	389	*/
385	block_put(b);	390	block_put(b);
386	return NULL;	391	return NULL;
387	}	392	}
388	void *node = fat_node_get(idx->dev_handle,	393	void *node = fat_node_get(idx->dev_handle,
389	idx->index);	394	idx->index);
390	block_put(b);	395	block_put(b);
391	return node;	396	return node;
392	}	397	}
393	}	398	}
394	block_put(b);	399	block_put(b);
395	}	400	}
396		401
397	return NULL;	402	return NULL;
398	}	403	}
399		404
400	static fs_index_t fat_index_get(void *node)	405	static fs_index_t fat_index_get(void *node)
401	{	406	{
402	fat_node_t fnodep = (fat_node_t )node;	407	fat_node_t fnodep = (fat_node_t )node;
403	if (!fnodep)	408	if (!fnodep)
404	return 0;	409	return 0;
405	return fnodep->idx->index;	410	return fnodep->idx->index;
406	}	411	}
407		412
408	static size_t fat_size_get(void *node)	413	static size_t fat_size_get(void *node)
409	{	414	{
410	return ((fat_node_t *)node)->size;	415	return ((fat_node_t *)node)->size;
411	}	416	}
412		417
413	static unsigned fat_lnkcnt_get(void *node)	418	static unsigned fat_lnkcnt_get(void *node)
414	{	419	{
415	return ((fat_node_t *)node)->lnkcnt;	420	return ((fat_node_t *)node)->lnkcnt;
416	}	421	}
417		422
418	static bool fat_has_children(void *node)	423	static bool fat_has_children(void *node)
419	{	424	{
420	fat_node_t nodep = (fat_node_t )node;	425	fat_node_t nodep = (fat_node_t )node;
421	unsigned bps;	426	unsigned bps;
422	unsigned dps;	427	unsigned dps;
423	unsigned blocks;	428	unsigned blocks;
424	block_t *b;	429	block_t *b;
425	unsigned i, j;	430	unsigned i, j;
426		431
427	if (nodep->type != FAT_DIRECTORY)	432	if (nodep->type != FAT_DIRECTORY)
428	return false;	433	return false;
429		434
430	bps = fat_bps_get(nodep->idx->dev_handle);	435	bps = fat_bps_get(nodep->idx->dev_handle);
431	dps = bps / sizeof(fat_dentry_t);	436	dps = bps / sizeof(fat_dentry_t);
432		437
433	blocks = nodep->size / bps + (nodep->size % bps != 0);	438	blocks = nodep->size / bps + (nodep->size % bps != 0);
434		439
435	for (i = 0; i < blocks; i++) {	440	for (i = 0; i < blocks; i++) {
436	unsigned dentries;	441	unsigned dentries;
437	fat_dentry_t *d;	442	fat_dentry_t *d;
438		443
439	b = fat_block_get(nodep, i);	444	b = fat_block_get(nodep, i);
440	dentries = (i == blocks - 1) ?	445	dentries = (i == blocks - 1) ?
441	nodep->size % sizeof(fat_dentry_t) :	446	nodep->size % sizeof(fat_dentry_t) :
442	dps;	447	dps;
443	for (j = 0; j < dentries; j++) {	448	for (j = 0; j < dentries; j++) {
444	d = ((fat_dentry_t *)b->data) + j;	449	d = ((fat_dentry_t *)b->data) + j;
445	switch (fat_classify_dentry(d)) {	450	switch (fat_classify_dentry(d)) {
446	case FAT_DENTRY_SKIP:	451	case FAT_DENTRY_SKIP:
447	continue;	452	continue;
448	case FAT_DENTRY_LAST:	453	case FAT_DENTRY_LAST:
449	block_put(b);	454	block_put(b);
450	return false;	455	return false;
451	default:	456	default:
452	case FAT_DENTRY_VALID:	457	case FAT_DENTRY_VALID:
453	block_put(b);	458	block_put(b);
454	return true;	459	return true;
455	}	460	}
456	block_put(b);	461	block_put(b);
457	return true;	462	return true;
458	}	463	}
459	block_put(b);	464	block_put(b);
460	}	465	}
461		466
462	return false;	467	return false;
463	}	468	}
464		469
465	static void *fat_root_get(dev_handle_t dev_handle)	470	static void *fat_root_get(dev_handle_t dev_handle)
466	{	471	{
467	return NULL; /* TODO */	472	return NULL; /* TODO */
468	}	473	}
469		474
470	static char fat_plb_get_char(unsigned pos)	475	static char fat_plb_get_char(unsigned pos)
471	{	476	{
472	return fat_reg.plb_ro[pos % PLB_SIZE];	477	return fat_reg.plb_ro[pos % PLB_SIZE];
473	}	478	}
474		479
475	static bool fat_is_directory(void *node)	480	static bool fat_is_directory(void *node)
476	{	481	{
477	return ((fat_node_t *)node)->type == FAT_DIRECTORY;	482	return ((fat_node_t *)node)->type == FAT_DIRECTORY;
478	}	483	}
479		484
480	static bool fat_is_file(void *node)	485	static bool fat_is_file(void *node)
481	{	486	{
482	return ((fat_node_t *)node)->type == FAT_FILE;	487	return ((fat_node_t *)node)->type == FAT_FILE;
483	}	488	}
484		489
485	/** libfs operations */	490	/** libfs operations */
486	libfs_ops_t fat_libfs_ops = {	491	libfs_ops_t fat_libfs_ops = {
487	.match = fat_match,	492	.match = fat_match,
488	.node_get = fat_node_get,	493	.node_get = fat_node_get,
489	.node_put = fat_node_put,	494	.node_put = fat_node_put,
490	.create = fat_create,	495	.create = fat_create,
491	.destroy = fat_destroy,	496	.destroy = fat_destroy,
492	.link = fat_link,	497	.link = fat_link,
493	.unlink = fat_unlink,	498	.unlink = fat_unlink,
494	.index_get = fat_index_get,	499	.index_get = fat_index_get,
495	.size_get = fat_size_get,	500	.size_get = fat_size_get,

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/fs/fat/fat_ops.c – Rev 2893 → 2910