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 and also 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.
         */
        idx->nodep->refcnt++;
        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)
{
    /* TODO */
}
 
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 2891	Rev 2893
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	#define FIN_KEY_DEV_HANDLE 0	-
54	#define FIN_KEY_INDEX 1	-
55		-
56	/** Hash table of FAT in-core nodes. */	-
57	hash_table_t fin_hash;	-
58		-
59	/** List of free FAT in-core nodes. */	53	/** List of free FAT nodes that still contain valid data. */
60	link_t ffn_head;	54	LIST_INITIALIZE(ffn_head);
61		55
62	#define FAT_NAME_LEN 8	56	#define FAT_NAME_LEN 8
63	#define FAT_EXT_LEN 3	57	#define FAT_EXT_LEN 3
64		58
65	#define FAT_PAD ' '	59	#define FAT_PAD ' '
66		60
67	#define FAT_DENTRY_UNUSED 0x00	61	#define FAT_DENTRY_UNUSED 0x00
68	#define FAT_DENTRY_E5_ESC 0x05	62	#define FAT_DENTRY_E5_ESC 0x05
69	#define FAT_DENTRY_DOT 0x2e	63	#define FAT_DENTRY_DOT 0x2e
70	#define FAT_DENTRY_ERASED 0xe5	64	#define FAT_DENTRY_ERASED 0xe5
71		65
72	static void dentry_name_canonify(fat_dentry_t d, char buf)	66	static void dentry_name_canonify(fat_dentry_t d, char buf)
73	{	67	{
74	int i;	68	int i;
75		69
76	for (i = 0; i < FAT_NAME_LEN; i++) {	70	for (i = 0; i < FAT_NAME_LEN; i++) {
77	if (d->name[i] == FAT_PAD) {	71	if (d->name[i] == FAT_PAD) {
78	buf++;	72	buf++;
79	break;	73	break;
80	}	74	}
81	if (d->name[i] == FAT_DENTRY_E5_ESC)	75	if (d->name[i] == FAT_DENTRY_E5_ESC)
82	*buf++ = 0xe5;	76	*buf++ = 0xe5;
83	else	77	else
84	*buf++ = d->name[i];	78	*buf++ = d->name[i];
85	}	79	}
86	if (d->ext[0] != FAT_PAD)	80	if (d->ext[0] != FAT_PAD)
87	*buf++ = '.';	81	*buf++ = '.';
88	for (i = 0; i < FAT_EXT_LEN; i++) {	82	for (i = 0; i < FAT_EXT_LEN; i++) {
89	if (d->ext[i] == FAT_PAD) {	83	if (d->ext[i] == FAT_PAD) {
90	*buf = '\0';	84	*buf = '\0';
91	return;	85	return;
92	}	86	}
93	if (d->ext[i] == FAT_DENTRY_E5_ESC)	87	if (d->ext[i] == FAT_DENTRY_E5_ESC)
94	*buf++ = 0xe5;	88	*buf++ = 0xe5;
95	else	89	else
96	*buf++ = d->ext[i];	90	*buf++ = d->ext[i];
97	}	91	}
98	}	92	}
99		93
100	/* TODO and also move somewhere else */	94	/* TODO and also move somewhere else */
101	typedef struct {	95	typedef struct {
102	void *data;	96	void *data;
103	} block_t;	97	} block_t;
104		98
105	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)
106	{	100	{
107	return NULL; /* TODO */	101	return NULL; /* TODO */
108	}	102	}
109		103
110	static void block_put(block_t *block)	104	static void block_put(block_t *block)
111	{	105	{
112	/* TODO */	106	/* TODO */
113	}	107	}
114		108
115	#define FAT_BS(b) ((fat_bs_t *)((b)->data))	109	#define FAT_BS(b) ((fat_bs_t *)((b)->data))
116		110
117	#define FAT_CLST_RES0 0x0000	111	#define FAT_CLST_RES0 0x0000
118	#define FAT_CLST_RES1 0x0001 /* internally used to mark root directory */	112	#define FAT_CLST_RES1 0x0001 /* internally used to mark root directory */
119	#define FAT_CLST_FIRST 0x0002	113	#define FAT_CLST_FIRST 0x0002
120	#define FAT_CLST_BAD 0xfff7	114	#define FAT_CLST_BAD 0xfff7
121	#define FAT_CLST_LAST1 0xfff8	115	#define FAT_CLST_LAST1 0xfff8
122	#define FAT_CLST_LAST8 0xffff	116	#define FAT_CLST_LAST8 0xffff
123		117
124	#define fat_block_get(np, off) \	118	#define fat_block_get(np, off) \
125	_fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))	119	_fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))
126		120
127	static block_t *	121	static block_t *
128	_fat_block_get(dev_handle_t dev_handle, fat_cluster_t fc, off_t offset)	122	_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)
129	{	123	{
130	block_t *bb;	124	block_t *bb;
131	block_t *b;	125	block_t *b;
132	unsigned bps;	126	unsigned bps;
133	unsigned spc;	127	unsigned spc;
134	unsigned rscnt; /* block address of the first FAT */	128	unsigned rscnt; /* block address of the first FAT */
135	unsigned fatcnt;	129	unsigned fatcnt;
136	unsigned rde;	130	unsigned rde;
137	unsigned rds; /* root directory size */	131	unsigned rds; /* root directory size */
138	unsigned sf;	132	unsigned sf;
139	unsigned ssa; /* size of the system area */	133	unsigned ssa; /* size of the system area */
140	unsigned clusters;	134	unsigned clusters;
141	fat_cluster_t clst = fc;	135	fat_cluster_t clst = firstc;
142	unsigned i;	136	unsigned i;
143		137
144	bb = block_get(dev_handle, BS_BLOCK);	138	bb = block_get(dev_handle, BS_BLOCK);
145	bps = uint16_t_le2host(FAT_BS(bb)->bps);	139	bps = uint16_t_le2host(FAT_BS(bb)->bps);
146	spc = FAT_BS(bb)->spc;	140	spc = FAT_BS(bb)->spc;
147	rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);	141	rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
148	fatcnt = FAT_BS(bb)->fatcnt;	142	fatcnt = FAT_BS(bb)->fatcnt;
149	rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);	143	rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
150	sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);	144	sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);
151	block_put(bb);	145	block_put(bb);
152		146
153	rds = (sizeof(fat_dentry_t) * rde) / bps;	147	rds = (sizeof(fat_dentry_t) * rde) / bps;
154	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);	148	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
155	ssa = rscnt + fatcnt * sf + rds;	149	ssa = rscnt + fatcnt * sf + rds;
156		150
157	if (fc == FAT_CLST_RES1) {	151	if (firstc == FAT_CLST_RES1) {
158	/* root directory special case */	152	/* root directory special case */
159	assert(offset < rds);	153	assert(offset < rds);
160	b = block_get(dev_handle, rscnt + fatcnt * sf + offset);	154	b = block_get(dev_handle, rscnt + fatcnt * sf + offset);
161	return b;	155	return b;
162	}	156	}
163		157
164	clusters = offset / spc;	158	clusters = offset / spc;
165	for (i = 0; i < clusters; i++) {	159	for (i = 0; i < clusters; i++) {
166	unsigned fsec; /* sector offset relative to FAT1 */	160	unsigned fsec; /* sector offset relative to FAT1 */
167	unsigned fidx; /* FAT1 entry index */	161	unsigned fidx; /* FAT1 entry index */
168		162
169	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);	163	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
170	fsec = (clst * sizeof(fat_cluster_t)) / bps;	164	fsec = (clst * sizeof(fat_cluster_t)) / bps;
171	fidx = clst % (bps / sizeof(fat_cluster_t));	165	fidx = clst % (bps / sizeof(fat_cluster_t));
172	/* read FAT1 */	166	/* read FAT1 */
173	b = block_get(dev_handle, rscnt + fsec);	167	b = block_get(dev_handle, rscnt + fsec);
174	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);	168	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
175	assert(clst != FAT_CLST_BAD);	169	assert(clst != FAT_CLST_BAD);
176	assert(clst < FAT_CLST_LAST1);	170	assert(clst < FAT_CLST_LAST1);
177	block_put(b);	171	block_put(b);
178	}	172	}
179		173
180	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +	174	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
181	offset % spc);	175	offset % spc);
182		176
183	return b;	177	return b;
184	}	178	}
185		179
186	static void fat_node_initialize(fat_node_t *node)	180	static void fat_node_initialize(fat_node_t *node)
187	{	181	{
188	node->idx = NULL;	182	node->idx = NULL;
189	node->type = 0;	183	node->type = 0;
190	link_initialize(&node->fin_link);	-
191	link_initialize(&node->ffn_link);	184	link_initialize(&node->ffn_link);
192	node->size = 0;	185	node->size = 0;
193	node->lnkcnt = 0;	186	node->lnkcnt = 0;
194	node->refcnt = 0;	187	node->refcnt = 0;
195	node->dirty = false;	188	node->dirty = false;
196	}	189	}
197		190
198	static uint16_t fat_bps_get(dev_handle_t dev_handle)	191	static uint16_t fat_bps_get(dev_handle_t dev_handle)
199	{	192	{
200	block_t *bb;	193	block_t *bb;
201	uint16_t bps;	194	uint16_t bps;
202		195
203	bb = block_get(dev_handle, BS_BLOCK);	196	bb = block_get(dev_handle, BS_BLOCK);
204	assert(bb != NULL);	197	assert(bb != NULL);
205	bps = uint16_t_le2host(FAT_BS(bb)->bps);	198	bps = uint16_t_le2host(FAT_BS(bb)->bps);
206	block_put(bb);	199	block_put(bb);
207		200
208	return bps;	201	return bps;
209	}	202	}
210		203
211	typedef enum {	204	typedef enum {
212	FAT_DENTRY_SKIP,	205	FAT_DENTRY_SKIP,
213	FAT_DENTRY_LAST,	206	FAT_DENTRY_LAST,
214	FAT_DENTRY_VALID	207	FAT_DENTRY_VALID
215	} fat_dentry_clsf_t;	208	} fat_dentry_clsf_t;
216		209
217	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)
218	{	211	{
219	if (d->attr & FAT_ATTR_VOLLABEL) {	212	if (d->attr & FAT_ATTR_VOLLABEL) {
220	/* volume label entry */	213	/* volume label entry */
221	return FAT_DENTRY_SKIP;	214	return FAT_DENTRY_SKIP;
222	}	215	}
223	if (d->name[0] == FAT_DENTRY_ERASED) {	216	if (d->name[0] == FAT_DENTRY_ERASED) {
224	/* not-currently-used entry */	217	/* not-currently-used entry */
225	return FAT_DENTRY_SKIP;	218	return FAT_DENTRY_SKIP;
226	}	219	}
227	if (d->name[0] == FAT_DENTRY_UNUSED) {	220	if (d->name[0] == FAT_DENTRY_UNUSED) {
228	/* never used entry */	221	/* never used entry */
229	return FAT_DENTRY_LAST;	222	return FAT_DENTRY_LAST;
230	}	223	}
231	if (d->name[0] == FAT_DENTRY_DOT) {	224	if (d->name[0] == FAT_DENTRY_DOT) {
232	/*	225	/*
233	* Most likely '.' or '..'.	226	* Most likely '.' or '..'.
234	* It cannot occur in a regular file name.	227	* It cannot occur in a regular file name.
235	*/	228	*/
236	return FAT_DENTRY_SKIP;	229	return FAT_DENTRY_SKIP;
237	}	230	}
238	return FAT_DENTRY_VALID;	231	return FAT_DENTRY_VALID;
239	}	232	}
240		233
241	static void fat_sync_node(fat_node_t *node)	234	static void fat_node_sync(fat_node_t *node)
242	{	235	{
243	/* TODO */	236	/* TODO */
244	}	237	}
245		238
246	/** Instantiate a FAT in-core node. */	239	/** Instantiate a FAT in-core node. */
247	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)
248	{	241	{
249	fat_idx_t *idx;	242	fat_idx_t *idx;
250	block_t *b;	243	block_t *b;
251	fat_dentry_t *d;	244	fat_dentry_t *d;
252	fat_node_t *nodep;	245	fat_node_t *nodep;
253	unsigned bps;	246	unsigned bps;
254	unsigned dps;	247	unsigned dps;
255		248
256	idx = fat_idx_get_by_index(dev_handle, index);	249	idx = fat_idx_get_by_index(dev_handle, index);
257	if (!idx)	250	if (!idx)
258	return NULL;	251	return NULL;
259		252
260	if (idx->nodep) {	253	if (idx->nodep) {
261	/*	254	/*
262	* We are lucky.	255	* We are lucky.
263	* The node is already instantiated in memory.	256	* The node is already instantiated in memory.
264	*/	257	*/
265	idx->nodep->refcnt++;	258	idx->nodep->refcnt++;
266	return idx->nodep;	259	return idx->nodep;
267	}	260	}
268		261
269	/*	262	/*
270	* We must instantiate the node from the file system.	263	* We must instantiate the node from the file system.
271	*/	264	*/
272		265
273	assert(idx->pfc);	266	assert(idx->pfc);
274		267
-		268	if (!list_empty(&ffn_head)) {
-		269	/* Try to use a cached unused node structure. */
-		270	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
-		271	if (nodep->dirty)
-		272	fat_node_sync(nodep);
-		273	list_remove(&nodep->ffn_link);
-		274	nodep->idx->nodep = NULL;
-		275	} else {
-		276	/* Try to allocate a new node structure. */
275	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));	277	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
276	if (!nodep)	278	if (!nodep)
277	return NULL;	279	return NULL;
-		280	}
278	fat_node_initialize(nodep);	281	fat_node_initialize(nodep);
279		282
280	bps = fat_bps_get(dev_handle);	283	bps = fat_bps_get(dev_handle);
281	dps = bps / sizeof(fat_dentry_t);	284	dps = bps / sizeof(fat_dentry_t);
282		285
-		286	/* Read the block that contains the dentry of interest. */
283	b = _fat_block_get(dev_handle, idx->pfc,	287	b = _fat_block_get(dev_handle, idx->pfc,
284	(idx->pdi * sizeof(fat_dentry_t)) / bps);	288	(idx->pdi * sizeof(fat_dentry_t)) / bps);
285		-
286	assert(b);	289	assert(b);
287		290
288	d = ((fat_dentry_t *)b->data) + (idx->pdi % dps);	291	d = ((fat_dentry_t *)b->data) + (idx->pdi % dps);
-		292	if (d->attr & FAT_ATTR_SUBDIR) {
-		293	/*
-		294	* The only directory which does not have this bit set is the
-		295	* root directory itself. The root directory node is handled
-		296	* and initialized elsewhere.
289	/* XXX */	297	*/
-		298	nodep->type = FAT_DIRECTORY;
-		299	} else {
-		300	nodep->type = FAT_FILE;
-		301	}
-		302	nodep->firstc = uint16_t_le2host(d->firstc);
-		303	nodep->size = uint32_t_le2host(d->size);
-		304	nodep->lnkcnt = 1;
-		305	nodep->refcnt = 1;
-		306
-		307	block_put(b);
-		308
-		309	/* Link the idx structure with the node structure. */
-		310	nodep->idx = idx;
-		311	idx->nodep = nodep;
-		312
-		313	return nodep;
290	}	314	}
291		315
292	static void fat_node_put(void *node)	316	static void fat_node_put(void *node)
293	{	317	{
294	/* TODO */	318	/* TODO */
295	}	319	}
296		320
297	static void *fat_create(int flags)	321	static void *fat_create(int flags)
298	{	322	{
299	return NULL; /* not supported at the moment */	323	return NULL; /* not supported at the moment */
300	}	324	}
301		325
302	static int fat_destroy(void *node)	326	static int fat_destroy(void *node)
303	{	327	{
304	return ENOTSUP; /* not supported at the moment */	328	return ENOTSUP; /* not supported at the moment */
305	}	329	}
306		330
307	static bool fat_link(void prnt, void chld, const char *name)	331	static bool fat_link(void prnt, void chld, const char *name)
308	{	332	{
309	return false; /* not supported at the moment */	333	return false; /* not supported at the moment */
310	}	334	}
311		335
312	static int fat_unlink(void prnt, void chld)	336	static int fat_unlink(void prnt, void chld)
313	{	337	{
314	return ENOTSUP; /* not supported at the moment */	338	return ENOTSUP; /* not supported at the moment */
315	}	339	}
316		340
317	static void fat_match(void prnt, const char *component)	341	static void fat_match(void prnt, const char *component)
318	{	342	{
319	fat_node_t parentp = (fat_node_t )prnt;	343	fat_node_t parentp = (fat_node_t )prnt;
320	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];	344	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
321	unsigned i, j;	345	unsigned i, j;
322	unsigned bps; /* bytes per sector */	346	unsigned bps; /* bytes per sector */
323	unsigned dps; /* dentries per sector */	347	unsigned dps; /* dentries per sector */
324	unsigned blocks;	348	unsigned blocks;
325	fat_dentry_t *d;	349	fat_dentry_t *d;
326	block_t *b;	350	block_t *b;
327		351
328	bps = fat_bps_get(parentp->idx->dev_handle);	352	bps = fat_bps_get(parentp->idx->dev_handle);
329	dps = bps / sizeof(fat_dentry_t);	353	dps = bps / sizeof(fat_dentry_t);
330	blocks = parentp->size / bps + (parentp->size % bps != 0);	354	blocks = parentp->size / bps + (parentp->size % bps != 0);
331	for (i = 0; i < blocks; i++) {	355	for (i = 0; i < blocks; i++) {
332	unsigned dentries;	356	unsigned dentries;
333		357
334	b = fat_block_get(parentp, i);	358	b = fat_block_get(parentp, i);
335	dentries = (i == blocks - 1) ?	359	dentries = (i == blocks - 1) ?
336	parentp->size % sizeof(fat_dentry_t) :	360	parentp->size % sizeof(fat_dentry_t) :
337	dps;	361	dps;
338	for (j = 0; j < dentries; j++) {	362	for (j = 0; j < dentries; j++) {
339	d = ((fat_dentry_t *)b->data) + j;	363	d = ((fat_dentry_t *)b->data) + j;
340	switch (fat_classify_dentry(d)) {	364	switch (fat_classify_dentry(d)) {
341	case FAT_DENTRY_SKIP:	365	case FAT_DENTRY_SKIP:
342	continue;	366	continue;
343	case FAT_DENTRY_LAST:	367	case FAT_DENTRY_LAST:
344	block_put(b);	368	block_put(b);
345	return NULL;	369	return NULL;
346	default:	370	default:
347	case FAT_DENTRY_VALID:	371	case FAT_DENTRY_VALID:
348	dentry_name_canonify(d, name);	372	dentry_name_canonify(d, name);
349	break;	373	break;
350	}	374	}
351	if (strcmp(name, component) == 0) {	375	if (strcmp(name, component) == 0) {
352	/* hit */	376	/* hit */
353	fat_idx_t *idx = fat_idx_get_by_pos(	377	fat_idx_t *idx = fat_idx_get_by_pos(
354	parentp->idx->dev_handle, parentp->firstc,	378	parentp->idx->dev_handle, parentp->firstc,
355	i * dps + j);	379	i * dps + j);
356	if (!idx) {	380	if (!idx) {
357	/*	381	/*
358	* Can happen if memory is low or if we	382	* Can happen if memory is low or if we
359	* run out of 32-bit indices.	383	* run out of 32-bit indices.
360	*/	384	*/
361	block_put(b);	385	block_put(b);
362	return NULL;	386	return NULL;
363	}	387	}
364	void *node = fat_node_get(idx->dev_handle,	388	void *node = fat_node_get(idx->dev_handle,
365	idx->index);	389	idx->index);
366	block_put(b);	390	block_put(b);
367	return node;	391	return node;
368	}	392	}
369	}	393	}
370	block_put(b);	394	block_put(b);
371	}	395	}
372		396
373	return NULL;	397	return NULL;
374	}	398	}
375		399
376	static fs_index_t fat_index_get(void *node)	400	static fs_index_t fat_index_get(void *node)
377	{	401	{
378	fat_node_t fnodep = (fat_node_t )node;	402	fat_node_t fnodep = (fat_node_t )node;
379	if (!fnodep)	403	if (!fnodep)
380	return 0;	404	return 0;
381	return fnodep->idx->index;	405	return fnodep->idx->index;
382	}	406	}
383		407
384	static size_t fat_size_get(void *node)	408	static size_t fat_size_get(void *node)
385	{	409	{
386	return ((fat_node_t *)node)->size;	410	return ((fat_node_t *)node)->size;
387	}	411	}
388		412
389	static unsigned fat_lnkcnt_get(void *node)	413	static unsigned fat_lnkcnt_get(void *node)
390	{	414	{
391	return ((fat_node_t *)node)->lnkcnt;	415	return ((fat_node_t *)node)->lnkcnt;
392	}	416	}
393		417
394	static bool fat_has_children(void *node)	418	static bool fat_has_children(void *node)
395	{	419	{
396	fat_node_t nodep = (fat_node_t )node;	420	fat_node_t nodep = (fat_node_t )node;
397	unsigned bps;	421	unsigned bps;
398	unsigned dps;	422	unsigned dps;
399	unsigned blocks;	423	unsigned blocks;
400	block_t *b;	424	block_t *b;
401	unsigned i, j;	425	unsigned i, j;
402		426
403	if (nodep->type != FAT_DIRECTORY)	427	if (nodep->type != FAT_DIRECTORY)
404	return false;	428	return false;
405		429
406	bps = fat_bps_get(nodep->idx->dev_handle);	430	bps = fat_bps_get(nodep->idx->dev_handle);
407	dps = bps / sizeof(fat_dentry_t);	431	dps = bps / sizeof(fat_dentry_t);
408		432
409	blocks = nodep->size / bps + (nodep->size % bps != 0);	433	blocks = nodep->size / bps + (nodep->size % bps != 0);
410		434
411	for (i = 0; i < blocks; i++) {	435	for (i = 0; i < blocks; i++) {
412	unsigned dentries;	436	unsigned dentries;
413	fat_dentry_t *d;	437	fat_dentry_t *d;
414		438
415	b = fat_block_get(nodep, i);	439	b = fat_block_get(nodep, i);
416	dentries = (i == blocks - 1) ?	440	dentries = (i == blocks - 1) ?
417	nodep->size % sizeof(fat_dentry_t) :	441	nodep->size % sizeof(fat_dentry_t) :
418	dps;	442	dps;
419	for (j = 0; j < dentries; j++) {	443	for (j = 0; j < dentries; j++) {
420	d = ((fat_dentry_t *)b->data) + j;	444	d = ((fat_dentry_t *)b->data) + j;
421	switch (fat_classify_dentry(d)) {	445	switch (fat_classify_dentry(d)) {
422	case FAT_DENTRY_SKIP:	446	case FAT_DENTRY_SKIP:
423	continue;	447	continue;
424	case FAT_DENTRY_LAST:	448	case FAT_DENTRY_LAST:
425	block_put(b);	449	block_put(b);
426	return false;	450	return false;
427	default:	451	default:
428	case FAT_DENTRY_VALID:	452	case FAT_DENTRY_VALID:
429	block_put(b);	453	block_put(b);
430	return true;	454	return true;
431	}	455	}
432	block_put(b);	456	block_put(b);
433	return true;	457	return true;
434	}	458	}
435	block_put(b);	459	block_put(b);
436	}	460	}
437		461
438	return false;	462	return false;
439	}	463	}
440		464
441	static void *fat_root_get(dev_handle_t dev_handle)	465	static void *fat_root_get(dev_handle_t dev_handle)
442	{	466	{
443	return fat_node_get(dev_handle, 0); /* TODO */	467	return NULL; /* TODO */
444	}	468	}
445		469
446	static char fat_plb_get_char(unsigned pos)	470	static char fat_plb_get_char(unsigned pos)
447	{	471	{
448	return fat_reg.plb_ro[pos % PLB_SIZE];	472	return fat_reg.plb_ro[pos % PLB_SIZE];
449	}	473	}
450		474
451	static bool fat_is_directory(void *node)	475	static bool fat_is_directory(void *node)
452	{	476	{
453	return ((fat_node_t *)node)->type == FAT_DIRECTORY;	477	return ((fat_node_t *)node)->type == FAT_DIRECTORY;
454	}	478	}
455		479
456	static bool fat_is_file(void *node)	480	static bool fat_is_file(void *node)
457	{	481	{
458	return ((fat_node_t *)node)->type == FAT_FILE;	482	return ((fat_node_t *)node)->type == FAT_FILE;
459	}	483	}
460		484
461	/** libfs operations */	485	/** libfs operations */
462	libfs_ops_t fat_libfs_ops = {	486	libfs_ops_t fat_libfs_ops = {
463	.match = fat_match,	487	.match = fat_match,
464	.node_get = fat_node_get,	488	.node_get = fat_node_get,
465	.node_put = fat_node_put,	489	.node_put = fat_node_put,
466	.create = fat_create,	490	.create = fat_create,
467	.destroy = fat_destroy,	491	.destroy = fat_destroy,
468	.link = fat_link,	492	.link = fat_link,

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/fs/fat/fat_ops.c – Rev 2891 → 2893