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
 
#define FIN_KEY_DEV_HANDLE  0
#define FIN_KEY_INDEX       1
 
/** Futex protecting both fin_hash and ffn_head. */
futex_t fin_futex = FUTEX_INITIALIZER;
 
/** Hash table of FAT in-core nodes. */
hash_table_t fin_hash;
 
/** List of free FAT in-core nodes. */
link_t 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_FIRST  0x0002
#define FAT_CLST_BAD    0xfff7
#define FAT_CLST_LAST1  0xfff8
#define FAT_CLST_LAST8  0xffff
 
/** Convert cluster number to an index within a FAT.
 *
 * Format Identifier and cluster numbering is considered.
 */
#define C2FAT_IDX(c)    (1 + (c) - FAT_CLST_FIRST)
 
static block_t *fat_block_get(dev_handle_t dev_handle, fs_index_t index,
    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;
    unsigned clst = index;
    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 (!index) {
        /* 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 = (C2FAT_IDX(clst) * sizeof(uint16_t)) / bps;
        fidx = C2FAT_IDX(clst) % (bps / sizeof(uint16_t));
        /* read FAT1 */
        b = block_get(dev_handle, rscnt + fsec);
        clst = uint16_t_le2host(((uint16_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)
{
    futex_initialize(&node->lock, 1);
    node->type = 0;
    node->index = 0;
    node->pindex = 0;
    node->dev_handle = 0;
    link_initialize(&node->fin_link);
    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_sync_node(fat_node_t *node)
{
    /* TODO */
}
 
/** Instantiate a FAT in-core node.
 *
 * FAT stores the info necessary for instantiation of a node in the parent of
 * that node.  This design necessitated the addition of the parent node index
 * parameter to this otherwise generic libfs API.
 */
static void *
fat_node_get(dev_handle_t dev_handle, fs_index_t index, fs_index_t pindex)
{
    link_t *lnk;
    fat_node_t *node = NULL;
    block_t *b;
    unsigned bps;
    unsigned dps;
    fat_dentry_t *d;
    unsigned i, j;
 
    unsigned long key[] = {
        [FIN_KEY_DEV_HANDLE] = dev_handle,
        [FIN_KEY_INDEX] = index
    };
 
    futex_down(&fin_futex);
    lnk = hash_table_find(&fin_hash, key);
    if (lnk) {
        /*
         * The in-core node was found in the hash table.
         */
        node = hash_table_get_instance(lnk, fat_node_t, fin_link);
        if (!node->refcnt++)
            list_remove(&node->ffn_link);
        futex_up(&fin_futex);
       
        /* Make sure that the node is fully instantiated. */
        futex_down(&node->lock);
        futex_up(&node->lock);
       
        return (void *) node;  
    }
 
    bps = fat_bps_get(dev_handle);
    dps = bps / sizeof(fat_dentry_t);
   
    if (!list_empty(&ffn_head)) {
        /*
         * We are going to reuse a node from the free list.
         */
        lnk = ffn_head.next;
        list_remove(lnk);
        node = list_get_instance(lnk, fat_node_t, ffn_link);
        assert(!node->refcnt);
        if (node->dirty)
            fat_sync_node(node);
        key[FIN_KEY_DEV_HANDLE] = node->dev_handle;
        key[FIN_KEY_INDEX] = node->index;
        hash_table_remove(&fin_hash, key, sizeof(key)/sizeof(*key));
    } else {
        /*
         * We need to allocate a new node.
         */
        node = malloc(sizeof(fat_node_t));
        if (!node)
            return NULL;
    }
    fat_node_initialize(node);
    node->refcnt++;
    node->lnkcnt++;
    node->dev_handle = dev_handle;
    node->index = index;
    node->pindex = pindex;
    key[FIN_KEY_DEV_HANDLE] = node->dev_handle;
    key[FIN_KEY_INDEX] = node->index;
    hash_table_insert(&fin_hash, key, &node->fin_link);
 
    /*
     * We have already put the node back to fin_hash.
     * The node is not yet fully instantiated so we lock it prior to
     * unlocking fin_hash.
     */
    futex_down(&node->lock);
    futex_up(&fin_futex);
 
    /*
     * Because of the design of the FAT file system, we have no clue about
     * how big (i.e. how many directory entries it contains) is the parent
     * of the node we are trying to instantiate.  However, we know that it
     * must contain a directory entry for our node of interest.  We simply
     * scan the parent until we find it.
     */
    for (i = 0; ; i++) {
        b = fat_block_get(node->dev_handle, node->pindex, i);
        for (j = 0; j < dps; j++) {
            d = ((fat_dentry_t *)b->data) + j;
            if (d->firstc == node->index)
                goto found;
        }
        block_put(b);
    }
   
found:
    if (!(d->attr & (FAT_ATTR_SUBDIR | FAT_ATTR_VOLLABEL)))
        node->type = FAT_FILE;
    if ((d->attr & FAT_ATTR_SUBDIR) || !index)
        node->type = FAT_DIRECTORY;
    assert((node->type == FAT_FILE) || (node->type == FAT_DIRECTORY));
   
    node->size = uint32_t_le2host(d->size);
    block_put(b);
 
    futex_up(&node->lock);
    return node;
}
 
static void fat_node_put(void *node)
{
    fat_node_t *nodep = (fat_node_t *)node;
 
    futex_down(&fin_futex);
    if (!--nodep->refcnt)
        list_append(&nodep->ffn_link, &ffn_head);
    futex_up(&fin_futex);
}
 
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->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->dev_handle, parentp->index, 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 */
                void *node = fat_node_get(parentp->dev_handle,
                    (fs_index_t)uint16_t_le2host(d->firstc),
                    parentp->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->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->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->dev_handle, nodep->index, 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 fat_node_get(dev_handle, 0, 0); 
}
 
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 2858	Rev 2859
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	53	#define FIN_KEY_DEV_HANDLE 0
54	#define FIN_KEY_INDEX 1	54	#define FIN_KEY_INDEX 1
55		55
56	/** Futex protecting both fin_hash and ffn_head. */	56	/** Futex protecting both fin_hash and ffn_head. */
57	futex_t fin_futex = FUTEX_INITIALIZER;	57	futex_t fin_futex = FUTEX_INITIALIZER;
58		58
59	/** Hash table of FAT in-core nodes. */	59	/** Hash table of FAT in-core nodes. */
60	hash_table_t fin_hash;	60	hash_table_t fin_hash;
61		61
62	/** List of free FAT in-core nodes. */	62	/** List of free FAT in-core nodes. */
63	link_t ffn_head;	63	link_t ffn_head;
64		64
65	#define FAT_NAME_LEN 8	65	#define FAT_NAME_LEN 8
66	#define FAT_EXT_LEN 3	66	#define FAT_EXT_LEN 3
67		67
68	#define FAT_PAD ' '	68	#define FAT_PAD ' '
69		69
70	#define FAT_DENTRY_UNUSED 0x00	70	#define FAT_DENTRY_UNUSED 0x00
71	#define FAT_DENTRY_E5_ESC 0x05	71	#define FAT_DENTRY_E5_ESC 0x05
72	#define FAT_DENTRY_DOT 0x2e	72	#define FAT_DENTRY_DOT 0x2e
73	#define FAT_DENTRY_ERASED 0xe5	73	#define FAT_DENTRY_ERASED 0xe5
74		74
75	static void dentry_name_canonify(fat_dentry_t d, char buf)	75	static void dentry_name_canonify(fat_dentry_t d, char buf)
76	{	76	{
77	int i;	77	int i;
78		78
79	for (i = 0; i < FAT_NAME_LEN; i++) {	79	for (i = 0; i < FAT_NAME_LEN; i++) {
80	if (d->name[i] == FAT_PAD) {	80	if (d->name[i] == FAT_PAD) {
81	buf++;	81	buf++;
82	break;	82	break;
83	}	83	}
84	if (d->name[i] == FAT_DENTRY_E5_ESC)	84	if (d->name[i] == FAT_DENTRY_E5_ESC)
85	*buf++ = 0xe5;	85	*buf++ = 0xe5;
86	else	86	else
87	*buf++ = d->name[i];	87	*buf++ = d->name[i];
88	}	88	}
89	if (d->ext[0] != FAT_PAD)	89	if (d->ext[0] != FAT_PAD)
90	*buf++ = '.';	90	*buf++ = '.';
91	for (i = 0; i < FAT_EXT_LEN; i++) {	91	for (i = 0; i < FAT_EXT_LEN; i++) {
92	if (d->ext[i] == FAT_PAD) {	92	if (d->ext[i] == FAT_PAD) {
93	*buf = '\0';	93	*buf = '\0';
94	return;	94	return;
95	}	95	}
96	if (d->ext[i] == FAT_DENTRY_E5_ESC)	96	if (d->ext[i] == FAT_DENTRY_E5_ESC)
97	*buf++ = 0xe5;	97	*buf++ = 0xe5;
98	else	98	else
99	*buf++ = d->ext[i];	99	*buf++ = d->ext[i];
100	}	100	}
101	}	101	}
102		102
103	/* TODO and also move somewhere else */	103	/* TODO and also move somewhere else */
104	typedef struct {	104	typedef struct {
105	void *data;	105	void *data;
106	} block_t;	106	} block_t;
107		107
108	static block_t *block_get(dev_handle_t dev_handle, off_t offset)	108	static block_t *block_get(dev_handle_t dev_handle, off_t offset)
109	{	109	{
110	return NULL; /* TODO */	110	return NULL; /* TODO */
111	}	111	}
112		112
113	static block_t *fat_block_get(dev_handle_t dev_handle, fs_index_t index,	-
114	off_t offset) {	-
115	return NULL; /* TODO */	-
116	}	-
117		-
118	static void block_put(block_t *block)	113	static void block_put(block_t *block)
119	{	114	{
120	/* TODO */	115	/* TODO */
121	}	116	}
122		117
-		118
-		119	#define FAT_BS(b) ((fat_bs_t *)((b)->data))
-		120
-		121	#define FAT_CLST_FIRST 0x0002
-		122	#define FAT_CLST_BAD 0xfff7
-		123	#define FAT_CLST_LAST1 0xfff8
-		124	#define FAT_CLST_LAST8 0xffff
-		125
-		126	/** Convert cluster number to an index within a FAT.
-		127	*
-		128	* Format Identifier and cluster numbering is considered.
-		129	*/
-		130	#define C2FAT_IDX(c) (1 + (c) - FAT_CLST_FIRST)
-		131
-		132	static block_t *fat_block_get(dev_handle_t dev_handle, fs_index_t index,
-		133	off_t offset)
-		134	{
-		135	block_t *bb;
-		136	block_t *b;
-		137	unsigned bps;
-		138	unsigned spc;
-		139	unsigned rscnt; /* block address of the first FAT */
-		140	unsigned fatcnt;
-		141	unsigned rde;
-		142	unsigned rds; /* root directory size */
-		143	unsigned sf;
-		144	unsigned ssa; /* size of the system area */
-		145	unsigned clusters;
-		146	unsigned clst = index;
-		147	unsigned i;
-		148
-		149	bb = block_get(dev_handle, BS_BLOCK);
-		150	bps = uint16_t_le2host(FAT_BS(bb)->bps);
-		151	spc = FAT_BS(bb)->spc;
-		152	rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
-		153	fatcnt = FAT_BS(bb)->fatcnt;
-		154	rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
-		155	sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);
-		156	block_put(bb);
-		157
-		158	rds = (sizeof(fat_dentry_t) * rde) / bps;
-		159	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
-		160	ssa = rscnt + fatcnt * sf + rds;
-		161
-		162	if (!index) {
-		163	/* root directory special case */
-		164	assert(offset < rds);
-		165	b = block_get(dev_handle, rscnt + fatcnt * sf + offset);
-		166	return b;
-		167	}
-		168
-		169	clusters = offset / spc;
-		170	for (i = 0; i < clusters; i++) {
-		171	unsigned fsec; /* sector offset relative to FAT1 */
-		172	unsigned fidx; /* FAT1 entry index */
-		173
-		174	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
-		175	fsec = (C2FAT_IDX(clst) * sizeof(uint16_t)) / bps;
-		176	fidx = C2FAT_IDX(clst) % (bps / sizeof(uint16_t));
-		177	/* read FAT1 */
-		178	b = block_get(dev_handle, rscnt + fsec);
-		179	clst = uint16_t_le2host(((uint16_t *)b->data)[fidx]);
-		180	assert(clst != FAT_CLST_BAD);
-		181	assert(clst < FAT_CLST_LAST1);
-		182	block_put(b);
-		183	}
-		184
-		185	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
-		186	offset % spc);
-		187
-		188	return b;
-		189	}
-		190
123	static void fat_node_initialize(fat_node_t *node)	191	static void fat_node_initialize(fat_node_t *node)
124	{	192	{
125	futex_initialize(&node->lock, 1);	193	futex_initialize(&node->lock, 1);
126	node->type = 0;	194	node->type = 0;
127	node->index = 0;	195	node->index = 0;
128	node->pindex = 0;	196	node->pindex = 0;
129	node->dev_handle = 0;	197	node->dev_handle = 0;
130	link_initialize(&node->fin_link);	198	link_initialize(&node->fin_link);
131	link_initialize(&node->ffn_link);	199	link_initialize(&node->ffn_link);
132	node->size = 0;	200	node->size = 0;
133	node->lnkcnt = 0;	201	node->lnkcnt = 0;
134	node->refcnt = 0;	202	node->refcnt = 0;
135	node->dirty = false;	203	node->dirty = false;
136	}	204	}
137		205
138	static uint16_t fat_bps_get(dev_handle_t dev_handle)	206	static uint16_t fat_bps_get(dev_handle_t dev_handle)
139	{	207	{
140	block_t *bb;	208	block_t *bb;
141	uint16_t bps;	209	uint16_t bps;
142		210
143	bb = block_get(dev_handle, BS_BLOCK);	211	bb = block_get(dev_handle, BS_BLOCK);
144	assert(bb != NULL);	212	assert(bb != NULL);
145	bps = uint16_t_le2host(((fat_bs_t *)bb->data)->bps);	213	bps = uint16_t_le2host(FAT_BS(bb)->bps);
146	block_put(bb);	214	block_put(bb);
147		215
148	return bps;	216	return bps;
149	}	217	}
150		218
151	typedef enum {	219	typedef enum {
152	FAT_DENTRY_SKIP,	220	FAT_DENTRY_SKIP,
153	FAT_DENTRY_LAST,	221	FAT_DENTRY_LAST,
154	FAT_DENTRY_VALID	222	FAT_DENTRY_VALID
155	} fat_dentry_clsf_t;	223	} fat_dentry_clsf_t;
156		224
157	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)	225	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)
158	{	226	{
159	if (d->attr & FAT_ATTR_VOLLABEL) {	227	if (d->attr & FAT_ATTR_VOLLABEL) {
160	/* volume label entry */	228	/* volume label entry */
161	return FAT_DENTRY_SKIP;	229	return FAT_DENTRY_SKIP;
162	}	230	}
163	if (d->name[0] == FAT_DENTRY_ERASED) {	231	if (d->name[0] == FAT_DENTRY_ERASED) {
164	/* not-currently-used entry */	232	/* not-currently-used entry */
165	return FAT_DENTRY_SKIP;	233	return FAT_DENTRY_SKIP;
166	}	234	}
167	if (d->name[0] == FAT_DENTRY_UNUSED) {	235	if (d->name[0] == FAT_DENTRY_UNUSED) {
168	/* never used entry */	236	/* never used entry */
169	return FAT_DENTRY_LAST;	237	return FAT_DENTRY_LAST;
170	}	238	}
171	if (d->name[0] == FAT_DENTRY_DOT) {	239	if (d->name[0] == FAT_DENTRY_DOT) {
172	/*	240	/*
173	* Most likely '.' or '..'.	241	* Most likely '.' or '..'.
174	* It cannot occur in a regular file name.	242	* It cannot occur in a regular file name.
175	*/	243	*/
176	return FAT_DENTRY_SKIP;	244	return FAT_DENTRY_SKIP;
177	}	245	}
178	return FAT_DENTRY_VALID;	246	return FAT_DENTRY_VALID;
179	}	247	}
180		248
181	static void fat_sync_node(fat_node_t *node)	249	static void fat_sync_node(fat_node_t *node)
182	{	250	{
183	/* TODO */	251	/* TODO */
184	}	252	}
185		253
186	/** Instantiate a FAT in-core node.	254	/** Instantiate a FAT in-core node.
187	*	255	*
188	* FAT stores the info necessary for instantiation of a node in the parent of	256	* FAT stores the info necessary for instantiation of a node in the parent of
189	* that node. This design necessitated the addition of the parent node index	257	* that node. This design necessitated the addition of the parent node index
190	* parameter to this otherwise generic libfs API.	258	* parameter to this otherwise generic libfs API.
191	*/	259	*/
192	static void *	260	static void *
193	fat_node_get(dev_handle_t dev_handle, fs_index_t index, fs_index_t pindex)	261	fat_node_get(dev_handle_t dev_handle, fs_index_t index, fs_index_t pindex)
194	{	262	{
195	link_t *lnk;	263	link_t *lnk;
196	fat_node_t *node = NULL;	264	fat_node_t *node = NULL;
197	block_t *b;	265	block_t *b;
198	unsigned bps;	266	unsigned bps;
199	unsigned dps;	267	unsigned dps;
200	fat_dentry_t *d;	268	fat_dentry_t *d;
201	unsigned i, j;	269	unsigned i, j;
202		270
203	unsigned long key[] = {	271	unsigned long key[] = {
204	[FIN_KEY_DEV_HANDLE] = dev_handle,	272	[FIN_KEY_DEV_HANDLE] = dev_handle,
205	[FIN_KEY_INDEX] = index	273	[FIN_KEY_INDEX] = index
206	};	274	};
207		275
208	futex_down(&fin_futex);	276	futex_down(&fin_futex);
209	lnk = hash_table_find(&fin_hash, key);	277	lnk = hash_table_find(&fin_hash, key);
210	if (lnk) {	278	if (lnk) {
211	/*	279	/*
212	* The in-core node was found in the hash table.	280	* The in-core node was found in the hash table.
213	*/	281	*/
214	node = hash_table_get_instance(lnk, fat_node_t, fin_link);	282	node = hash_table_get_instance(lnk, fat_node_t, fin_link);
215	if (!node->refcnt++)	283	if (!node->refcnt++)
216	list_remove(&node->ffn_link);	284	list_remove(&node->ffn_link);
217	futex_up(&fin_futex);	285	futex_up(&fin_futex);
218		286
219	/* Make sure that the node is fully instantiated. */	287	/* Make sure that the node is fully instantiated. */
220	futex_down(&node->lock);	288	futex_down(&node->lock);
221	futex_up(&node->lock);	289	futex_up(&node->lock);
222		290
223	return (void *) node;	291	return (void *) node;
224	}	292	}
225		293
226	bps = fat_bps_get(dev_handle);	294	bps = fat_bps_get(dev_handle);
227	dps = bps / sizeof(fat_dentry_t);	295	dps = bps / sizeof(fat_dentry_t);
228		296
229	if (!list_empty(&ffn_head)) {	297	if (!list_empty(&ffn_head)) {
230	/*	298	/*
231	* We are going to reuse a node from the free list.	299	* We are going to reuse a node from the free list.
232	*/	300	*/
233	lnk = ffn_head.next;	301	lnk = ffn_head.next;
234	list_remove(lnk);	302	list_remove(lnk);
235	node = list_get_instance(lnk, fat_node_t, ffn_link);	303	node = list_get_instance(lnk, fat_node_t, ffn_link);
236	assert(!node->refcnt);	304	assert(!node->refcnt);
237	if (node->dirty)	305	if (node->dirty)
238	fat_sync_node(node);	306	fat_sync_node(node);
239	key[FIN_KEY_DEV_HANDLE] = node->dev_handle;	307	key[FIN_KEY_DEV_HANDLE] = node->dev_handle;
240	key[FIN_KEY_INDEX] = node->index;	308	key[FIN_KEY_INDEX] = node->index;
241	hash_table_remove(&fin_hash, key, sizeof(key)/sizeof(*key));	309	hash_table_remove(&fin_hash, key, sizeof(key)/sizeof(*key));
242	} else {	310	} else {
243	/*	311	/*
244	* We need to allocate a new node.	312	* We need to allocate a new node.
245	*/	313	*/
246	node = malloc(sizeof(fat_node_t));	314	node = malloc(sizeof(fat_node_t));
247	if (!node)	315	if (!node)
248	return NULL;	316	return NULL;
249	}	317	}
250	fat_node_initialize(node);	318	fat_node_initialize(node);
251	node->refcnt++;	319	node->refcnt++;
252	node->lnkcnt++;	320	node->lnkcnt++;
253	node->dev_handle = dev_handle;	321	node->dev_handle = dev_handle;
254	node->index = index;	322	node->index = index;
255	node->pindex = pindex;	323	node->pindex = pindex;
256	key[FIN_KEY_DEV_HANDLE] = node->dev_handle;	324	key[FIN_KEY_DEV_HANDLE] = node->dev_handle;
257	key[FIN_KEY_INDEX] = node->index;	325	key[FIN_KEY_INDEX] = node->index;
258	hash_table_insert(&fin_hash, key, &node->fin_link);	326	hash_table_insert(&fin_hash, key, &node->fin_link);
259		327
260	/*	328	/*
261	* We have already put the node back to fin_hash.	329	* We have already put the node back to fin_hash.
262	* The node is not yet fully instantiated so we lock it prior to	330	* The node is not yet fully instantiated so we lock it prior to
263	* unlocking fin_hash.	331	* unlocking fin_hash.
264	*/	332	*/
265	futex_down(&node->lock);	333	futex_down(&node->lock);
266	futex_up(&fin_futex);	334	futex_up(&fin_futex);
267		335
268	/*	336	/*
269	* Because of the design of the FAT file system, we have no clue about	337	* Because of the design of the FAT file system, we have no clue about
270	* how big (i.e. how many directory entries it contains) is the parent	338	* how big (i.e. how many directory entries it contains) is the parent
271	* of the node we are trying to instantiate. However, we know that it	339	* of the node we are trying to instantiate. However, we know that it
272	* must contain a directory entry for our node of interest. We simply	340	* must contain a directory entry for our node of interest. We simply
273	* scan the parent until we find it.	341	* scan the parent until we find it.
274	*/	342	*/
275	for (i = 0; ; i++) {	343	for (i = 0; ; i++) {
276	b = fat_block_get(node->dev_handle, node->pindex, i);	344	b = fat_block_get(node->dev_handle, node->pindex, i);
277	for (j = 0; j < dps; j++) {	345	for (j = 0; j < dps; j++) {
278	d = ((fat_dentry_t *)b->data) + j;	346	d = ((fat_dentry_t *)b->data) + j;
279	if (d->firstc == node->index)	347	if (d->firstc == node->index)
280	goto found;	348	goto found;
281	}	349	}
282	block_put(b);	350	block_put(b);
283	}	351	}
284		352
285	found:	353	found:
286	if (!(d->attr & (FAT_ATTR_SUBDIR \| FAT_ATTR_VOLLABEL)))	354	if (!(d->attr & (FAT_ATTR_SUBDIR \| FAT_ATTR_VOLLABEL)))
287	node->type = FAT_FILE;	355	node->type = FAT_FILE;
288	if ((d->attr & FAT_ATTR_SUBDIR) \|\| !index)	356	if ((d->attr & FAT_ATTR_SUBDIR) \|\| !index)
289	node->type = FAT_DIRECTORY;	357	node->type = FAT_DIRECTORY;
290	assert((node->type == FAT_FILE) \|\| (node->type == FAT_DIRECTORY));	358	assert((node->type == FAT_FILE) \|\| (node->type == FAT_DIRECTORY));
291		359
292	node->size = uint32_t_le2host(d->size);	360	node->size = uint32_t_le2host(d->size);
293	block_put(b);	361	block_put(b);
294		362
295	futex_up(&node->lock);	363	futex_up(&node->lock);
296	return node;	364	return node;
297	}	365	}
298		366
299	static void fat_node_put(void *node)	367	static void fat_node_put(void *node)
300	{	368	{
301	fat_node_t nodep = (fat_node_t )node;	369	fat_node_t nodep = (fat_node_t )node;
302		370
303	futex_down(&fin_futex);	371	futex_down(&fin_futex);
304	if (!--nodep->refcnt)	372	if (!--nodep->refcnt)
305	list_append(&nodep->ffn_link, &ffn_head);	373	list_append(&nodep->ffn_link, &ffn_head);
306	futex_up(&fin_futex);	374	futex_up(&fin_futex);
307	}	375	}
308		376
309	static void *fat_create(int flags)	377	static void *fat_create(int flags)
310	{	378	{
311	return NULL; /* not supported at the moment */	379	return NULL; /* not supported at the moment */
312	}	380	}
313		381
314	static int fat_destroy(void *node)	382	static int fat_destroy(void *node)
315	{	383	{
316	return ENOTSUP; /* not supported at the moment */	384	return ENOTSUP; /* not supported at the moment */
317	}	385	}
318		386
319	static bool fat_link(void prnt, void chld, const char *name)	387	static bool fat_link(void prnt, void chld, const char *name)
320	{	388	{
321	return false; /* not supported at the moment */	389	return false; /* not supported at the moment */
322	}	390	}
323		391
324	static int fat_unlink(void prnt, void chld)	392	static int fat_unlink(void prnt, void chld)
325	{	393	{
326	return ENOTSUP; /* not supported at the moment */	394	return ENOTSUP; /* not supported at the moment */
327	}	395	}
328		396
329	static void fat_match(void prnt, const char *component)	397	static void fat_match(void prnt, const char *component)
330	{	398	{
331	fat_node_t parentp = (fat_node_t )prnt;	399	fat_node_t parentp = (fat_node_t )prnt;
332	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];	400	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
333	unsigned i, j;	401	unsigned i, j;
334	unsigned bps; /* bytes per sector */	402	unsigned bps; /* bytes per sector */
335	unsigned dps; /* dentries per sector */	403	unsigned dps; /* dentries per sector */
336	unsigned blocks;	404	unsigned blocks;
337	fat_dentry_t *d;	405	fat_dentry_t *d;
338	block_t *b;	406	block_t *b;
339		407
340	bps = fat_bps_get(parentp->dev_handle);	408	bps = fat_bps_get(parentp->dev_handle);
341	dps = bps / sizeof(fat_dentry_t);	409	dps = bps / sizeof(fat_dentry_t);
342	blocks = parentp->size / bps + (parentp->size % bps != 0);	410	blocks = parentp->size / bps + (parentp->size % bps != 0);
343	for (i = 0; i < blocks; i++) {	411	for (i = 0; i < blocks; i++) {
344	unsigned dentries;	412	unsigned dentries;
345		413
346	b = fat_block_get(parentp->dev_handle, parentp->index, i);	414	b = fat_block_get(parentp->dev_handle, parentp->index, i);
347	dentries = (i == blocks - 1) ?	415	dentries = (i == blocks - 1) ?
348	parentp->size % sizeof(fat_dentry_t) :	416	parentp->size % sizeof(fat_dentry_t) :
349	dps;	417	dps;
350	for (j = 0; j < dentries; j++) {	418	for (j = 0; j < dentries; j++) {
351	d = ((fat_dentry_t *)b->data) + j;	419	d = ((fat_dentry_t *)b->data) + j;
352	switch (fat_classify_dentry(d)) {	420	switch (fat_classify_dentry(d)) {
353	case FAT_DENTRY_SKIP:	421	case FAT_DENTRY_SKIP:
354	continue;	422	continue;
355	case FAT_DENTRY_LAST:	423	case FAT_DENTRY_LAST:
356	block_put(b);	424	block_put(b);
357	return NULL;	425	return NULL;
358	default:	426	default:
359	case FAT_DENTRY_VALID:	427	case FAT_DENTRY_VALID:
360	dentry_name_canonify(d, name);	428	dentry_name_canonify(d, name);
361	break;	429	break;
362	}	430	}
363	if (strcmp(name, component) == 0) {	431	if (strcmp(name, component) == 0) {
364	/* hit */	432	/* hit */
365	void *node = fat_node_get(parentp->dev_handle,	433	void *node = fat_node_get(parentp->dev_handle,
366	(fs_index_t)uint16_t_le2host(d->firstc),	434	(fs_index_t)uint16_t_le2host(d->firstc),
367	parentp->index);	435	parentp->index);
368	block_put(b);	436	block_put(b);
369	return node;	437	return node;
370	}	438	}
371	}	439	}
372	block_put(b);	440	block_put(b);
373	}	441	}
374		442
375	return NULL;	443	return NULL;
376	}	444	}
377		445
378	static fs_index_t fat_index_get(void *node)	446	static fs_index_t fat_index_get(void *node)
379	{	447	{
380	fat_node_t fnodep = (fat_node_t )node;	448	fat_node_t fnodep = (fat_node_t )node;
381	if (!fnodep)	449	if (!fnodep)
382	return 0;	450	return 0;
383	return fnodep->index;	451	return fnodep->index;
384	}	452	}
385		453
386	static size_t fat_size_get(void *node)	454	static size_t fat_size_get(void *node)
387	{	455	{
388	return ((fat_node_t *)node)->size;	456	return ((fat_node_t *)node)->size;
389	}	457	}
390		458
391	static unsigned fat_lnkcnt_get(void *node)	459	static unsigned fat_lnkcnt_get(void *node)
392	{	460	{
393	return ((fat_node_t *)node)->lnkcnt;	461	return ((fat_node_t *)node)->lnkcnt;
394	}	462	}
395		463
396	static bool fat_has_children(void *node)	464	static bool fat_has_children(void *node)
397	{	465	{
398	fat_node_t nodep = (fat_node_t )node;	466	fat_node_t nodep = (fat_node_t )node;
399	unsigned bps;	467	unsigned bps;
400	unsigned dps;	468	unsigned dps;
401	unsigned blocks;	469	unsigned blocks;
402	block_t *b;	470	block_t *b;
403	unsigned i, j;	471	unsigned i, j;
404		472
405	if (nodep->type != FAT_DIRECTORY)	473	if (nodep->type != FAT_DIRECTORY)
406	return false;	474	return false;
407		475
408	bps = fat_bps_get(nodep->dev_handle);	476	bps = fat_bps_get(nodep->dev_handle);
409	dps = bps / sizeof(fat_dentry_t);	477	dps = bps / sizeof(fat_dentry_t);
410		478
411	blocks = nodep->size / bps + (nodep->size % bps != 0);	479	blocks = nodep->size / bps + (nodep->size % bps != 0);
412		480
413	for (i = 0; i < blocks; i++) {	481	for (i = 0; i < blocks; i++) {
414	unsigned dentries;	482	unsigned dentries;
415	fat_dentry_t *d;	483	fat_dentry_t *d;
416		484
417	b = fat_block_get(nodep->dev_handle, nodep->index, i);	485	b = fat_block_get(nodep->dev_handle, nodep->index, i);
418	dentries = (i == blocks - 1) ?	486	dentries = (i == blocks - 1) ?
419	nodep->size % sizeof(fat_dentry_t) :	487	nodep->size % sizeof(fat_dentry_t) :
420	dps;	488	dps;
421	for (j = 0; j < dentries; j++) {	489	for (j = 0; j < dentries; j++) {
422	d = ((fat_dentry_t *)b->data) + j;	490	d = ((fat_dentry_t *)b->data) + j;
423	switch (fat_classify_dentry(d)) {	491	switch (fat_classify_dentry(d)) {
424	case FAT_DENTRY_SKIP:	492	case FAT_DENTRY_SKIP:
425	continue;	493	continue;
426	case FAT_DENTRY_LAST:	494	case FAT_DENTRY_LAST:
427	block_put(b);	495	block_put(b);

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/fs/fat/fat_ops.c @ 3314 – Rev 2858 → 2859