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 block_t *fat_block_get(dev_handle_t dev_handle, fs_index_t index,
    off_t offset) {
    return NULL;    /* TODO */
}
 
static void block_put(block_t *block)
{
    /* TODO */
}
 
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_t *)bb->data)->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_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 = NULL,
    .destroy = NULL,
    .link = NULL,
    .unlink = NULL,
    .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 2855	Rev 2856
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		50
50	#define BS_BLOCK 0	51	#define BS_BLOCK 0
51		52
52	#define FIN_KEY_DEV_HANDLE 0	53	#define FIN_KEY_DEV_HANDLE 0
53	#define FIN_KEY_INDEX 1	54	#define FIN_KEY_INDEX 1
54		55
-		56	/** Futex protecting both fin_hash and ffn_head. */
-		57	futex_t fin_futex = FUTEX_INITIALIZER;
-		58
55	/** Hash table of FAT in-core nodes. */	59	/** Hash table of FAT in-core nodes. */
56	hash_table_t fin_hash;	60	hash_table_t fin_hash;
57		61
58	/** List of free FAT in-core nodes. */	62	/** List of free FAT in-core nodes. */
59	link_t ffn_head;	63	link_t ffn_head;
60		64
61	#define FAT_NAME_LEN 8	65	#define FAT_NAME_LEN 8
62	#define FAT_EXT_LEN 3	66	#define FAT_EXT_LEN 3
63		67
64	#define FAT_PAD ' '	68	#define FAT_PAD ' '
65		69
66	#define FAT_DENTRY_UNUSED 0x00	70	#define FAT_DENTRY_UNUSED 0x00
67	#define FAT_DENTRY_E5_ESC 0x05	71	#define FAT_DENTRY_E5_ESC 0x05
68	#define FAT_DENTRY_DOT 0x2e	72	#define FAT_DENTRY_DOT 0x2e
69	#define FAT_DENTRY_ERASED 0xe5	73	#define FAT_DENTRY_ERASED 0xe5
70		74
71	static void dentry_name_canonify(fat_dentry_t d, char buf)	75	static void dentry_name_canonify(fat_dentry_t d, char buf)
72	{	76	{
73	int i;	77	int i;
74		78
75	for (i = 0; i < FAT_NAME_LEN; i++) {	79	for (i = 0; i < FAT_NAME_LEN; i++) {
76	if (d->name[i] == FAT_PAD) {	80	if (d->name[i] == FAT_PAD) {
77	buf++;	81	buf++;
78	break;	82	break;
79	}	83	}
80	if (d->name[i] == FAT_DENTRY_E5_ESC)	84	if (d->name[i] == FAT_DENTRY_E5_ESC)
81	*buf++ = 0xe5;	85	*buf++ = 0xe5;
82	else	86	else
83	*buf++ = d->name[i];	87	*buf++ = d->name[i];
84	}	88	}
85	if (d->ext[0] != FAT_PAD)	89	if (d->ext[0] != FAT_PAD)
86	*buf++ = '.';	90	*buf++ = '.';
87	for (i = 0; i < FAT_EXT_LEN; i++) {	91	for (i = 0; i < FAT_EXT_LEN; i++) {
88	if (d->ext[i] == FAT_PAD) {	92	if (d->ext[i] == FAT_PAD) {
89	*buf = '\0';	93	*buf = '\0';
90	return;	94	return;
91	}	95	}
92	if (d->ext[i] == FAT_DENTRY_E5_ESC)	96	if (d->ext[i] == FAT_DENTRY_E5_ESC)
93	*buf++ = 0xe5;	97	*buf++ = 0xe5;
94	else	98	else
95	*buf++ = d->ext[i];	99	*buf++ = d->ext[i];
96	}	100	}
97	}	101	}
98		102
99	/* TODO and also move somewhere else */	103	/* TODO and also move somewhere else */
100	typedef struct {	104	typedef struct {
101	void *data;	105	void *data;
102	} block_t;	106	} block_t;
103		107
104	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)
105	{	109	{
106	return NULL; /* TODO */	110	return NULL; /* TODO */
107	}	111	}
108		112
109	static block_t *fat_block_get(dev_handle_t dev_handle, fs_index_t index,	113	static block_t *fat_block_get(dev_handle_t dev_handle, fs_index_t index,
110	off_t offset) {	114	off_t offset) {
111	return NULL; /* TODO */	115	return NULL; /* TODO */
112	}	116	}
113		117
114	static void block_put(block_t *block)	118	static void block_put(block_t *block)
115	{	119	{
116	/* TODO */	120	/* TODO */
117	}	121	}
118		122
119	static void fat_node_initialize(fat_node_t *node)	123	static void fat_node_initialize(fat_node_t *node)
120	{	124	{
-		125	futex_initialize(&node->lock, 1);
121	node->type = 0;	126	node->type = 0;
122	node->index = 0;	127	node->index = 0;
123	node->pindex = 0;	128	node->pindex = 0;
124	node->dev_handle = 0;	129	node->dev_handle = 0;
125	link_initialize(&node->fin_link);	130	link_initialize(&node->fin_link);
126	link_initialize(&node->ffn_link);	131	link_initialize(&node->ffn_link);
127	node->size = 0;	132	node->size = 0;
128	node->lnkcnt = 0;	133	node->lnkcnt = 0;
129	node->refcnt = 0;	134	node->refcnt = 0;
130	node->dirty = false;	135	node->dirty = false;
131	}	136	}
132		137
133	static uint16_t fat_bps_get(dev_handle_t dev_handle)	138	static uint16_t fat_bps_get(dev_handle_t dev_handle)
134	{	139	{
135	block_t *bb;	140	block_t *bb;
136	uint16_t bps;	141	uint16_t bps;
137		142
138	bb = block_get(dev_handle, BS_BLOCK);	143	bb = block_get(dev_handle, BS_BLOCK);
139	assert(bb != NULL);	144	assert(bb != NULL);
140	bps = uint16_t_le2host(((fat_bs_t *)bb->data)->bps);	145	bps = uint16_t_le2host(((fat_bs_t *)bb->data)->bps);
141	block_put(bb);	146	block_put(bb);
142		147
143	return bps;	148	return bps;
144	}	149	}
145		150
146	typedef enum {	151	typedef enum {
147	FAT_DENTRY_SKIP,	152	FAT_DENTRY_SKIP,
148	FAT_DENTRY_LAST,	153	FAT_DENTRY_LAST,
149	FAT_DENTRY_VALID	154	FAT_DENTRY_VALID
150	} fat_dentry_clsf_t;	155	} fat_dentry_clsf_t;
151		156
152	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)	157	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)
153	{	158	{
154	if (d->attr & FAT_ATTR_VOLLABEL) {	159	if (d->attr & FAT_ATTR_VOLLABEL) {
155	/* volume label entry */	160	/* volume label entry */
156	return FAT_DENTRY_SKIP;	161	return FAT_DENTRY_SKIP;
157	}	162	}
158	if (d->name[0] == FAT_DENTRY_ERASED) {	163	if (d->name[0] == FAT_DENTRY_ERASED) {
159	/* not-currently-used entry */	164	/* not-currently-used entry */
160	return FAT_DENTRY_SKIP;	165	return FAT_DENTRY_SKIP;
161	}	166	}
162	if (d->name[0] == FAT_DENTRY_UNUSED) {	167	if (d->name[0] == FAT_DENTRY_UNUSED) {
163	/* never used entry */	168	/* never used entry */
164	return FAT_DENTRY_LAST;	169	return FAT_DENTRY_LAST;
165	}	170	}
166	if (d->name[0] == FAT_DENTRY_DOT) {	171	if (d->name[0] == FAT_DENTRY_DOT) {
167	/*	172	/*
168	* Most likely '.' or '..'.	173	* Most likely '.' or '..'.
169	* It cannot occur in a regular file name.	174	* It cannot occur in a regular file name.
170	*/	175	*/
171	return FAT_DENTRY_SKIP;	176	return FAT_DENTRY_SKIP;
172	}	177	}
173	return FAT_DENTRY_VALID;	178	return FAT_DENTRY_VALID;
174	}	179	}
175		180
176	static void fat_sync_node(fat_node_t *node)	181	static void fat_sync_node(fat_node_t *node)
177	{	182	{
178	/* TODO */	183	/* TODO */
179	}	184	}
180		185
181	/** Instantiate a FAT in-core node.	186	/** Instantiate a FAT in-core node.
182	*	187	*
183	* FAT stores the info necessary for instantiation of a node in the parent of	188	* FAT stores the info necessary for instantiation of a node in the parent of
184	* that node. This design necessitated the addition of the parent node index	189	* that node. This design necessitated the addition of the parent node index
185	* parameter to this otherwise generic libfs API.	190	* parameter to this otherwise generic libfs API.
186	*/	191	*/
187	static void *	192	static void *
188	fat_node_get(dev_handle_t dev_handle, fs_index_t index, fs_index_t pindex)	193	fat_node_get(dev_handle_t dev_handle, fs_index_t index, fs_index_t pindex)
189	{	194	{
190	link_t *lnk;	195	link_t *lnk;
191	fat_node_t *node = NULL;	196	fat_node_t *node = NULL;
192	block_t *b;	197	block_t *b;
193	unsigned bps;	198	unsigned bps;
194	unsigned dps;	199	unsigned dps;
195	fat_dentry_t *d;	200	fat_dentry_t *d;
196	unsigned i, j;	201	unsigned i, j;
197		202
198	unsigned long key[] = {	203	unsigned long key[] = {
199	[FIN_KEY_DEV_HANDLE] = dev_handle,	204	[FIN_KEY_DEV_HANDLE] = dev_handle,
200	[FIN_KEY_INDEX] = index	205	[FIN_KEY_INDEX] = index
201	};	206	};
202		207
-		208	futex_down(&fin_futex);
203	lnk = hash_table_find(&fin_hash, key);	209	lnk = hash_table_find(&fin_hash, key);
204	if (lnk) {	210	if (lnk) {
205	/*	211	/*
206	* The in-core node was found in the hash table.	212	* The in-core node was found in the hash table.
207	*/	213	*/
208	node = hash_table_get_instance(lnk, fat_node_t, fin_link);	214	node = hash_table_get_instance(lnk, fat_node_t, fin_link);
209	if (!node->refcnt++)	215	if (!node->refcnt++)
210	list_remove(&node->ffn_link);	216	list_remove(&node->ffn_link);
-		217	futex_up(&fin_futex);
-		218
-		219	/* Make sure that the node is fully instantiated. */
-		220	futex_down(&node->lock);
-		221	futex_up(&node->lock);
-		222
211	return (void *) node;	223	return (void *) node;
212	}	224	}
213		225
214	bps = fat_bps_get(dev_handle);	226	bps = fat_bps_get(dev_handle);
215	dps = bps / sizeof(fat_dentry_t);	227	dps = bps / sizeof(fat_dentry_t);
216		228
217	if (!list_empty(&ffn_head)) {	229	if (!list_empty(&ffn_head)) {
218	/*	230	/*
219	* We are going to reuse a node from the free list.	231	* We are going to reuse a node from the free list.
220	*/	232	*/
221	lnk = ffn_head.next;	233	lnk = ffn_head.next;
222	list_remove(lnk);	234	list_remove(lnk);
223	node = list_get_instance(lnk, fat_node_t, ffn_link);	235	node = list_get_instance(lnk, fat_node_t, ffn_link);
224	assert(!node->refcnt);	236	assert(!node->refcnt);
225	if (node->dirty)	237	if (node->dirty)
226	fat_sync_node(node);	238	fat_sync_node(node);
227	key[FIN_KEY_DEV_HANDLE] = node->dev_handle;	239	key[FIN_KEY_DEV_HANDLE] = node->dev_handle;
228	key[FIN_KEY_INDEX] = node->index;	240	key[FIN_KEY_INDEX] = node->index;
229	hash_table_remove(&fin_hash, key, sizeof(key)/sizeof(*key));	241	hash_table_remove(&fin_hash, key, sizeof(key)/sizeof(*key));
230	} else {	242	} else {
231	/*	243	/*
232	* We need to allocate a new node.	244	* We need to allocate a new node.
233	*/	245	*/
234	node = malloc(sizeof(fat_node_t));	246	node = malloc(sizeof(fat_node_t));
235	if (!node)	247	if (!node)
236	return NULL;	248	return NULL;
237	}	249	}
238	fat_node_initialize(node);	250	fat_node_initialize(node);
239	node->refcnt++;	251	node->refcnt++;
240	node->lnkcnt++;	252	node->lnkcnt++;
241	node->dev_handle = dev_handle;	253	node->dev_handle = dev_handle;
242	node->index = index;	254	node->index = index;
243	node->pindex = pindex;	255	node->pindex = pindex;
-		256	key[FIN_KEY_DEV_HANDLE] = node->dev_handle;
-		257	key[FIN_KEY_INDEX] = node->index;
-		258	hash_table_insert(&fin_hash, key, &node->fin_link);
-		259
-		260	/*
-		261	* We have already put the node back to fin_hash.
-		262	* The node is not yet fully instantiated so we lock it prior to
-		263	* unlocking fin_hash.
-		264	*/
-		265	futex_down(&node->lock);
-		266	futex_up(&fin_futex);
244		267
245	/*	268	/*
246	* Because of the design of the FAT file system, we have no clue about	269	* Because of the design of the FAT file system, we have no clue about
247	* how big (i.e. how many directory entries it contains) is the parent	270	* how big (i.e. how many directory entries it contains) is the parent
248	* of the node we are trying to instantiate. However, we know that it	271	* of the node we are trying to instantiate. However, we know that it
249	* must contain a directory entry for our node of interest. We simply	272	* must contain a directory entry for our node of interest. We simply
250	* scan the parent until we find it.	273	* scan the parent until we find it.
251	*/	274	*/
252	for (i = 0; ; i++) {	275	for (i = 0; ; i++) {
253	b = fat_block_get(node->dev_handle, node->pindex, i);	276	b = fat_block_get(node->dev_handle, node->pindex, i);
254	for (j = 0; j < dps; j++) {	277	for (j = 0; j < dps; j++) {
255	d = ((fat_dentry_t *)b->data) + j;	278	d = ((fat_dentry_t *)b->data) + j;
256	if (d->firstc == node->index)	279	if (d->firstc == node->index)
257	goto found;	280	goto found;
258	}	281	}
259	block_put(b);	282	block_put(b);
260	}	283	}
261		284
262	found:	285	found:
263	if (!(d->attr & (FAT_ATTR_SUBDIR \| FAT_ATTR_VOLLABEL)))	286	if (!(d->attr & (FAT_ATTR_SUBDIR \| FAT_ATTR_VOLLABEL)))
264	node->type = FAT_FILE;	287	node->type = FAT_FILE;
265	if ((d->attr & FAT_ATTR_SUBDIR) \|\| !index)	288	if ((d->attr & FAT_ATTR_SUBDIR) \|\| !index)
266	node->type = FAT_DIRECTORY;	289	node->type = FAT_DIRECTORY;
267	assert((node->type == FAT_FILE) \|\| (node->type == FAT_DIRECTORY));	290	assert((node->type == FAT_FILE) \|\| (node->type == FAT_DIRECTORY));
268		291
269	node->size = uint32_t_le2host(d->size);	292	node->size = uint32_t_le2host(d->size);
270	block_put(b);	293	block_put(b);
271		-
272	key[FIN_KEY_DEV_HANDLE] = node->dev_handle;	-
273	key[FIN_KEY_INDEX] = node->index;	-
274	hash_table_insert(&fin_hash, key, &node->fin_link);	-
275		294
-		295	futex_up(&node->lock);
276	return node;	296	return node;
277	}	297	}
278		298
279	static void fat_node_put(void *node)	299	static void fat_node_put(void *node)
280	{	300	{
281	fat_node_t nodep = (fat_node_t )node;	301	fat_node_t nodep = (fat_node_t )node;
282		302
-		303	futex_down(&fin_futex);
283	if (nodep->refcnt-- == 1)	304	if (!--nodep->refcnt)
284	list_append(&nodep->ffn_link, &ffn_head);	305	list_append(&nodep->ffn_link, &ffn_head);
-		306	futex_up(&fin_futex);
285	}	307	}
286		308
287	static void fat_match(void prnt, const char *component)	309	static void fat_match(void prnt, const char *component)
288	{	310	{
289	fat_node_t parentp = (fat_node_t )prnt;	311	fat_node_t parentp = (fat_node_t )prnt;
290	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];	312	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
291	unsigned i, j;	313	unsigned i, j;
292	unsigned bps; /* bytes per sector */	314	unsigned bps; /* bytes per sector */
293	unsigned dps; /* dentries per sector */	315	unsigned dps; /* dentries per sector */
294	unsigned blocks;	316	unsigned blocks;
295	fat_dentry_t *d;	317	fat_dentry_t *d;
296	block_t *b;	318	block_t *b;
297		319
298	bps = fat_bps_get(parentp->dev_handle);	320	bps = fat_bps_get(parentp->dev_handle);
299	dps = bps / sizeof(fat_dentry_t);	321	dps = bps / sizeof(fat_dentry_t);
300	blocks = parentp->size / bps + (parentp->size % bps != 0);	322	blocks = parentp->size / bps + (parentp->size % bps != 0);
301	for (i = 0; i < blocks; i++) {	323	for (i = 0; i < blocks; i++) {
302	unsigned dentries;	324	unsigned dentries;
303		325
304	b = fat_block_get(parentp->dev_handle, parentp->index, i);	326	b = fat_block_get(parentp->dev_handle, parentp->index, i);
305	dentries = (i == blocks - 1) ?	327	dentries = (i == blocks - 1) ?
306	parentp->size % sizeof(fat_dentry_t) :	328	parentp->size % sizeof(fat_dentry_t) :
307	dps;	329	dps;
308	for (j = 0; j < dentries; j++) {	330	for (j = 0; j < dentries; j++) {
309	d = ((fat_dentry_t *)b->data) + j;	331	d = ((fat_dentry_t *)b->data) + j;
310	switch (fat_classify_dentry(d)) {	332	switch (fat_classify_dentry(d)) {
311	case FAT_DENTRY_SKIP:	333	case FAT_DENTRY_SKIP:
312	continue;	334	continue;
313	case FAT_DENTRY_LAST:	335	case FAT_DENTRY_LAST:
314	block_put(b);	336	block_put(b);
315	return NULL;	337	return NULL;
316	default:	338	default:
317	case FAT_DENTRY_VALID:	339	case FAT_DENTRY_VALID:
318	dentry_name_canonify(d, name);	340	dentry_name_canonify(d, name);
319	break;	341	break;
320	}	342	}
321	if (strcmp(name, component) == 0) {	343	if (strcmp(name, component) == 0) {
322	/* hit */	344	/* hit */
323	void *node = fat_node_get(parentp->dev_handle,	345	void *node = fat_node_get(parentp->dev_handle,
324	(fs_index_t)uint16_t_le2host(d->firstc),	346	(fs_index_t)uint16_t_le2host(d->firstc),
325	parentp->index);	347	parentp->index);
326	block_put(b);	348	block_put(b);
327	return node;	349	return node;
328	}	350	}
329	}	351	}
330	block_put(b);	352	block_put(b);
331	}	353	}
332		354
333	return NULL;	355	return NULL;
334	}	356	}
335		357
336	static fs_index_t fat_index_get(void *node)	358	static fs_index_t fat_index_get(void *node)
337	{	359	{
338	fat_node_t fnodep = (fat_node_t )node;	360	fat_node_t fnodep = (fat_node_t )node;
339	if (!fnodep)	361	if (!fnodep)
340	return 0;	362	return 0;
341	return fnodep->index;	363	return fnodep->index;
342	}	364	}
343		365
344	static size_t fat_size_get(void *node)	366	static size_t fat_size_get(void *node)
345	{	367	{
346	return ((fat_node_t *)node)->size;	368	return ((fat_node_t *)node)->size;
347	}	369	}
348		370
349	static unsigned fat_lnkcnt_get(void *node)	371	static unsigned fat_lnkcnt_get(void *node)
350	{	372	{
351	return ((fat_node_t *)node)->lnkcnt;	373	return ((fat_node_t *)node)->lnkcnt;
352	}	374	}
353		375
354	static bool fat_has_children(void *node)	376	static bool fat_has_children(void *node)
355	{	377	{
356	fat_node_t nodep = (fat_node_t )node;	378	fat_node_t nodep = (fat_node_t )node;
357	unsigned bps;	379	unsigned bps;
358	unsigned dps;	380	unsigned dps;
359	unsigned blocks;	381	unsigned blocks;
360	block_t *b;	382	block_t *b;
361	unsigned i, j;	383	unsigned i, j;
362		384
363	if (nodep->type != FAT_DIRECTORY)	385	if (nodep->type != FAT_DIRECTORY)
364	return false;	386	return false;
365		387
366	bps = fat_bps_get(nodep->dev_handle);	388	bps = fat_bps_get(nodep->dev_handle);
367	dps = bps / sizeof(fat_dentry_t);	389	dps = bps / sizeof(fat_dentry_t);
368		390
369	blocks = nodep->size / bps + (nodep->size % bps != 0);	391	blocks = nodep->size / bps + (nodep->size % bps != 0);
370		392
371	for (i = 0; i < blocks; i++) {	393	for (i = 0; i < blocks; i++) {
372	unsigned dentries;	394	unsigned dentries;
373	fat_dentry_t *d;	395	fat_dentry_t *d;
374		396
375	b = fat_block_get(nodep->dev_handle, nodep->index, i);	397	b = fat_block_get(nodep->dev_handle, nodep->index, i);
376	dentries = (i == blocks - 1) ?	398	dentries = (i == blocks - 1) ?
377	nodep->size % sizeof(fat_dentry_t) :	399	nodep->size % sizeof(fat_dentry_t) :
378	dps;	400	dps;
379	for (j = 0; j < dentries; j++) {	401	for (j = 0; j < dentries; j++) {
380	d = ((fat_dentry_t *)b->data) + j;	402	d = ((fat_dentry_t *)b->data) + j;
381	switch (fat_classify_dentry(d)) {	403	switch (fat_classify_dentry(d)) {
382	case FAT_DENTRY_SKIP:	404	case FAT_DENTRY_SKIP:
383	continue;	405	continue;
384	case FAT_DENTRY_LAST:	406	case FAT_DENTRY_LAST:
385	block_put(b);	407	block_put(b);
386	return false;	408	return false;
387	default:	409	default:
388	case FAT_DENTRY_VALID:	410	case FAT_DENTRY_VALID:
389	block_put(b);	411	block_put(b);
390	return true;	412	return true;
391	}	413	}
392	block_put(b);	414	block_put(b);
393	return true;	415	return true;
394	}	416	}
395	block_put(b);	417	block_put(b);
396	}	418	}
397		419
398	return false;	420	return false;
399	}	421	}
400		422
401	static void *fat_root_get(dev_handle_t dev_handle)	423	static void *fat_root_get(dev_handle_t dev_handle)
402	{	424	{
403	return fat_node_get(dev_handle, 0, 0);	425	return fat_node_get(dev_handle, 0, 0);
404	}	426	}
405		427
406	static char fat_plb_get_char(unsigned pos)	428	static char fat_plb_get_char(unsigned pos)
407	{	429	{
408	return fat_reg.plb_ro[pos % PLB_SIZE];	430	return fat_reg.plb_ro[pos % PLB_SIZE];
409	}	431	}
410		432
411	static bool fat_is_directory(void *node)	433	static bool fat_is_directory(void *node)
412	{	434	{
413	return ((fat_node_t *)node)->type == FAT_DIRECTORY;	435	return ((fat_node_t *)node)->type == FAT_DIRECTORY;
414	}	436	}
415		437
416	static bool fat_is_file(void *node)	438	static bool fat_is_file(void *node)
417	{	439	{
418	return ((fat_node_t *)node)->type == FAT_FILE;	440	return ((fat_node_t *)node)->type == FAT_FILE;
419	}	441	}
420		442
421	/** libfs operations */	443	/** libfs operations */
422	libfs_ops_t fat_libfs_ops = {	444	libfs_ops_t fat_libfs_ops = {
423	.match = fat_match,	445	.match = fat_match,
424	.node_get = fat_node_get,	446	.node_get = fat_node_get,
425	.node_put = fat_node_put,	447	.node_put = fat_node_put,
426	.create = NULL,	448	.create = NULL,
427	.destroy = NULL,	449	.destroy = NULL,
428	.link = NULL,	450	.link = NULL,
429	.unlink = NULL,	451	.unlink = NULL,
430	.index_get = fat_index_get,	452	.index_get = fat_index_get,
431	.size_get = fat_size_get,	453	.size_get = fat_size_get,
432	.lnkcnt_get = fat_lnkcnt_get,	454	.lnkcnt_get = fat_lnkcnt_get,
433	.has_children = fat_has_children,	455	.has_children = fat_has_children,
434	.root_get = fat_root_get,	456	.root_get = fat_root_get,
435	.plb_get_char = fat_plb_get_char,	457	.plb_get_char = fat_plb_get_char,
436	.is_directory = fat_is_directory,	458	.is_directory = fat_is_directory,
437	.is_file = fat_is_file	459	.is_file = fat_is_file
438	};	460	};
439		461
440	void fat_lookup(ipc_callid_t rid, ipc_call_t *request)	462	void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
441	{	463	{
442	libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);	464	libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
443	}	465	}
444		466
445	/**	467	/**
446	* @}	468	* @}
447	*/	469	*/
448		470

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/fs/fat/fat_ops.c – Rev 2855 → 2856