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 <ipc/services.h>
#include <ipc/devmap.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>
#include <sys/mman.h>
 
#define BS_BLOCK        0
#define BS_SIZE         512
 
/** Futex protecting the list of cached free FAT nodes. */
static futex_t ffn_futex = FUTEX_INITIALIZER;
 
/** List of cached free FAT nodes. */
static 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)
            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];
    }
    *buf = '\0';
}
 
static int dev_phone = -1;      /* FIXME */
static void *dev_buffer = NULL;     /* FIXME */
 
/* TODO move somewhere else */
typedef struct {
    void *data;
    size_t size;
} block_t;
 
static block_t *block_get(dev_handle_t dev_handle, off_t offset, size_t bs)
{
    /* FIXME */
    block_t *b;
    off_t bufpos = 0;
    size_t buflen = 0;
    off_t pos = offset * bs;
 
    assert(dev_phone != -1);
    assert(dev_buffer);
 
    b = malloc(sizeof(block_t));
    if (!b)
        return NULL;
   
    b->data = malloc(bs);
    if (!b->data) {
        free(b);
        return NULL;
    }
    b->size = bs;
 
    if (!libfs_blockread(dev_phone, dev_buffer, &bufpos, &buflen, &pos,
        b->data, bs, bs)) {
        free(b->data);
        free(b);
        return NULL;
    }
 
    return b;
}
 
static void block_put(block_t *block)
{
    /* FIXME */
    free(block->data);
    free(block);
}
 
#define FAT_BS(b)       ((fat_bs_t *)((b)->data))
 
#define FAT_CLST_RES0   0x0000
#define FAT_CLST_RES1   0x0001
#define FAT_CLST_FIRST  0x0002
#define FAT_CLST_BAD    0xfff7
#define FAT_CLST_LAST1  0xfff8
#define FAT_CLST_LAST8  0xffff
 
/* internally used to mark root directory's parent */
#define FAT_CLST_ROOTPAR    FAT_CLST_RES0
/* internally used to mark root directory */
#define FAT_CLST_ROOT       FAT_CLST_RES1
 
#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, BS_SIZE);
    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_ROOT) {
        /* root directory special case */
        assert(offset < rds);
        b = block_get(dev_handle, rscnt + fatcnt * sf + offset, bps);
        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, bps);
        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, bps);
 
    return b;
}
 
static void fat_node_initialize(fat_node_t *node)
{
    futex_initialize(&node->lock, 1);
    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, BS_SIZE);
    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 */
}
 
/** Internal version of fat_node_get().
 *
 * @param idxp      Locked index structure.
 */
static void *fat_node_get_core(fat_idx_t *idxp)
{
    block_t *b;
    fat_dentry_t *d;
    fat_node_t *nodep;
    unsigned bps;
    unsigned dps;
 
    if (idxp->nodep) {
        /*
         * We are lucky.
         * The node is already instantiated in memory.
         */
        futex_down(&idxp->nodep->lock);
        if (!idxp->nodep->refcnt++)
            list_remove(&nodep->ffn_link);
        futex_up(&idxp->nodep->lock);
        return idxp->nodep;
    }
 
    /*
     * We must instantiate the node from the file system.
     */
   
    assert(idxp->pfc);
 
    futex_down(&ffn_futex);
    if (!list_empty(&ffn_head)) {
        /* Try to use a cached free node structure. */
        fat_idx_t *idxp_tmp;
        nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
        if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
            goto skip_cache;
        idxp_tmp = nodep->idx;
        if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
            futex_up(&nodep->lock);
            goto skip_cache;
        }
        list_remove(&nodep->ffn_link);
        futex_up(&ffn_futex);
        if (nodep->dirty)
            fat_node_sync(nodep);
        idxp_tmp->nodep = NULL;
        futex_up(&nodep->lock);
        futex_up(&idxp_tmp->lock);
    } else {
skip_cache:
        /* Try to allocate a new node structure. */
        futex_up(&ffn_futex);
        nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
        if (!nodep)
            return NULL;
    }
    fat_node_initialize(nodep);
 
    bps = fat_bps_get(idxp->dev_handle);
    dps = bps / sizeof(fat_dentry_t);
 
    /* Read the block that contains the dentry of interest. */
    b = _fat_block_get(idxp->dev_handle, idxp->pfc,
        (idxp->pdi * sizeof(fat_dentry_t)) / bps);
    assert(b);
 
    d = ((fat_dentry_t *)b->data) + (idxp->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;
        /*
         * TODO: determine the size by walking FAT. Surprisingly, the
         * 'size' filed of the FAT dentry is not defined for the
         * directory entry type.
         */
        nodep->size = 64 * sizeof(fat_dentry_t);
    } else {
        nodep->type = FAT_FILE;
        nodep->size = uint32_t_le2host(d->size);
    }
    nodep->firstc = uint16_t_le2host(d->firstc);
    nodep->lnkcnt = 1;
    nodep->refcnt = 1;
 
    block_put(b);
 
    /* Link the idx structure with the node structure. */
    nodep->idx = idxp;
    idxp->nodep = nodep;
 
    return nodep;
}
 
/** Instantiate a FAT in-core node. */
static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
{
    void *node;
    fat_idx_t *idxp;
 
    idxp = fat_idx_get_by_index(dev_handle, index);
    if (!idxp)
        return NULL;
    /* idxp->lock held */
    node = fat_node_get_core(idxp);
    futex_up(&idxp->lock);
    return node;
}
 
static void fat_node_put(void *node)
{
    fat_node_t *nodep = (fat_node_t *)node;
 
    futex_down(&nodep->lock);
    if (!--nodep->refcnt) {
        futex_down(&ffn_futex);
        list_append(&nodep->ffn_link, &ffn_head);
        futex_up(&ffn_futex);
    }
    futex_up(&nodep->lock);
}
 
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;
 
    futex_down(&parentp->idx->lock);
    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);
                futex_up(&parentp->idx->lock);
                return NULL;
            default:
            case FAT_DENTRY_VALID:
                dentry_name_canonify(d, name);
                break;
            }
            if (stricmp(name, component) == 0) {
                /* hit */
                void *node;
                /*
                 * Assume tree hierarchy for locking.  We
                 * already have the parent and now we are going
                 * to lock the child.  Never lock in the oposite
                 * order.
                 */
                fat_idx_t *idx = fat_idx_get_by_pos(
                    parentp->idx->dev_handle, parentp->firstc,
                    i * dps + j);
                futex_up(&parentp->idx->lock);
                if (!idx) {
                    /*
                     * Can happen if memory is low or if we
                     * run out of 32-bit indices.
                     */
                    block_put(b);
                    return NULL;
                }
                node = fat_node_get_core(idx);
                futex_up(&idx->lock);
                block_put(b);
                return node;
            }
        }
        block_put(b);
    }
    futex_up(&parentp->idx->lock);
    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;
 
    futex_down(&nodep->idx->lock);
    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);
                futex_up(&nodep->idx->lock);
                return false;
            default:
            case FAT_DENTRY_VALID:
                block_put(b);
                futex_up(&nodep->idx->lock);
                return true;
            }
            block_put(b);
            futex_up(&nodep->idx->lock);
            return true;
        }
        block_put(b);
    }
 
    futex_up(&nodep->idx->lock);
    return false;
}
 
static void *fat_root_get(dev_handle_t dev_handle)
{
    return fat_node_get(dev_handle, 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_mounted(ipc_callid_t rid, ipc_call_t *request)
{
    dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request);
    block_t *bb;
    uint16_t bps;
    uint16_t rde;
    int rc;
 
    /*
     * For now, we don't bother to remember dev_handle, dev_phone or
     * dev_buffer in some data structure. We use global variables because we
     * know there will be at most one mount on this file system.
     * Of course, this is a huge TODO item.
     */
    dev_buffer = mmap(NULL, BS_SIZE, PROTO_READ | PROTO_WRITE,
        MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
   
    if (!dev_buffer) {
        ipc_answer_0(rid, ENOMEM);
        return;
    }
 
    dev_phone = ipc_connect_me_to(PHONE_NS, SERVICE_DEVMAP,
        DEVMAP_CONNECT_TO_DEVICE, dev_handle);
 
    if (dev_phone < 0) {
        munmap(dev_buffer, BS_SIZE);
        ipc_answer_0(rid, dev_phone);
        return;
    }
 
    rc = ipc_share_out_start(dev_phone, dev_buffer,
        AS_AREA_READ | AS_AREA_WRITE);
    if (rc != EOK) {
            munmap(dev_buffer, BS_SIZE);
        ipc_answer_0(rid, rc);
        return;
    }
 
    /* Read the number of root directory entries. */
    bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);
    bps = uint16_t_le2host(FAT_BS(bb)->bps);
    rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
    block_put(bb);
 
    if (bps != BS_SIZE) {
        munmap(dev_buffer, BS_SIZE);
        ipc_answer_0(rid, ENOTSUP);
        return;
    }
 
    rc = fat_idx_init_by_dev_handle(dev_handle);
    if (rc != EOK) {
            munmap(dev_buffer, BS_SIZE);
        ipc_answer_0(rid, rc);
        return;
    }
 
    /* Initialize the root node. */
    fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t));
    if (!rootp) {
            munmap(dev_buffer, BS_SIZE);
        fat_idx_fini_by_dev_handle(dev_handle);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    fat_node_initialize(rootp);
 
    fat_idx_t *ridxp = fat_idx_get_by_pos(dev_handle, FAT_CLST_ROOTPAR, 0);
    if (!ridxp) {
            munmap(dev_buffer, BS_SIZE);
        free(rootp);
        fat_idx_fini_by_dev_handle(dev_handle);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    assert(ridxp->index == 0);
    /* ridxp->lock held */
 
    rootp->type = FAT_DIRECTORY;
    rootp->firstc = FAT_CLST_ROOT;
    rootp->refcnt = 1;
    rootp->size = rde * sizeof(fat_dentry_t);
    rootp->idx = ridxp;
    ridxp->nodep = rootp;
   
    futex_up(&ridxp->lock);
 
    ipc_answer_0(rid, EOK);
}
 
void fat_mount(ipc_callid_t rid, ipc_call_t *request)
{
    ipc_answer_0(rid, ENOTSUP);
}
 
void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
{
    libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
}
 
void fat_read(ipc_callid_t rid, ipc_call_t *request)
{
    dev_handle_t dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
    fs_index_t index = (fs_index_t)IPC_GET_ARG2(*request);
    off_t pos = (off_t)IPC_GET_ARG3(*request);
    fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index);
    if (!nodep) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
 
    ipc_callid_t callid;
    size_t len;
    if (!ipc_data_write_receive(&callid, &len)) {
        fat_node_put(nodep);
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
 
    if (nodep->type == FAT_FILE) {
        /* TODO */
        fat_node_put(nodep);
        ipc_answer_0(callid, ENOTSUP);
        ipc_answer_0(rid, ENOTSUP);
        return;
    } else {
        assert(nodep->type == FAT_DIRECTORY);
        /* TODO */
        fat_node_put(nodep);
        ipc_answer_0(callid, ENOTSUP);
        ipc_answer_0(rid, ENOTSUP);
        return;
    }
 
    fat_node_put(nodep);
}
 
/**
 * @}
 */
 

Rev 3282	Rev 3307
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 <ipc/services.h>	42	#include <ipc/services.h>
43	#include <ipc/devmap.h>	43	#include <ipc/devmap.h>
44	#include <async.h>	44	#include <async.h>
45	#include <errno.h>	45	#include <errno.h>
46	#include <string.h>	46	#include <string.h>
47	#include <byteorder.h>	47	#include <byteorder.h>
48	#include <libadt/hash_table.h>	48	#include <libadt/hash_table.h>
49	#include <libadt/list.h>	49	#include <libadt/list.h>
50	#include <assert.h>	50	#include <assert.h>
51	#include <futex.h>	51	#include <futex.h>
52	#include <sys/mman.h>	52	#include <sys/mman.h>
53		53
54	#define BS_BLOCK 0	54	#define BS_BLOCK 0
55	#define BS_SIZE 512	55	#define BS_SIZE 512
56		56
57	/** Futex protecting the list of cached free FAT nodes. */	57	/** Futex protecting the list of cached free FAT nodes. */
58	static futex_t ffn_futex = FUTEX_INITIALIZER;	58	static futex_t ffn_futex = FUTEX_INITIALIZER;
59		59
60	/** List of cached free FAT nodes. */	60	/** List of cached free FAT nodes. */
61	static LIST_INITIALIZE(ffn_head);	61	static LIST_INITIALIZE(ffn_head);
62		62
63	#define FAT_NAME_LEN 8	63	#define FAT_NAME_LEN 8
64	#define FAT_EXT_LEN 3	64	#define FAT_EXT_LEN 3
65		65
66	#define FAT_PAD ' '	66	#define FAT_PAD ' '
67		67
68	#define FAT_DENTRY_UNUSED 0x00	68	#define FAT_DENTRY_UNUSED 0x00
69	#define FAT_DENTRY_E5_ESC 0x05	69	#define FAT_DENTRY_E5_ESC 0x05
70	#define FAT_DENTRY_DOT 0x2e	70	#define FAT_DENTRY_DOT 0x2e
71	#define FAT_DENTRY_ERASED 0xe5	71	#define FAT_DENTRY_ERASED 0xe5
72		72
73	static void dentry_name_canonify(fat_dentry_t d, char buf)	73	static void dentry_name_canonify(fat_dentry_t d, char buf)
74	{	74	{
75	int i;	75	int i;
76		76
77	for (i = 0; i < FAT_NAME_LEN; i++) {	77	for (i = 0; i < FAT_NAME_LEN; i++) {
78	if (d->name[i] == FAT_PAD)	78	if (d->name[i] == FAT_PAD)
79	break;	79	break;
80	if (d->name[i] == FAT_DENTRY_E5_ESC)	80	if (d->name[i] == FAT_DENTRY_E5_ESC)
81	*buf++ = 0xe5;	81	*buf++ = 0xe5;
82	else	82	else
83	*buf++ = d->name[i];	83	*buf++ = d->name[i];
84	}	84	}
85	if (d->ext[0] != FAT_PAD)	85	if (d->ext[0] != FAT_PAD)
86	*buf++ = '.';	86	*buf++ = '.';
87	for (i = 0; i < FAT_EXT_LEN; i++) {	87	for (i = 0; i < FAT_EXT_LEN; i++) {
88	if (d->ext[i] == FAT_PAD) {	88	if (d->ext[i] == FAT_PAD) {
89	*buf = '\0';	89	*buf = '\0';
90	return;	90	return;
91	}	91	}
92	if (d->ext[i] == FAT_DENTRY_E5_ESC)	92	if (d->ext[i] == FAT_DENTRY_E5_ESC)
93	*buf++ = 0xe5;	93	*buf++ = 0xe5;
94	else	94	else
95	*buf++ = d->ext[i];	95	*buf++ = d->ext[i];
96	}	96	}
97	*buf = '\0';	97	*buf = '\0';
98	}	98	}
99		99
100	static int dev_phone = -1; /* FIXME */	100	static int dev_phone = -1; /* FIXME */
101	static void dev_buffer = NULL; / FIXME */	101	static void dev_buffer = NULL; / FIXME */
102		102
103	/* TODO move somewhere else */	103	/* TODO move somewhere else */
104	typedef struct {	104	typedef struct {
105	void *data;	105	void *data;
106	size_t size;	106	size_t size;
107	} block_t;	107	} block_t;
108		108
109	static block_t *block_get(dev_handle_t dev_handle, off_t offset, size_t bs)	109	static block_t *block_get(dev_handle_t dev_handle, off_t offset, size_t bs)
110	{	110	{
111	/* FIXME */	111	/* FIXME */
112	block_t *b;	112	block_t *b;
113	off_t bufpos = 0;	113	off_t bufpos = 0;
114	size_t buflen = 0;	114	size_t buflen = 0;
115	off_t pos = offset * bs;	115	off_t pos = offset * bs;
116		116
117	assert(dev_phone != -1);	117	assert(dev_phone != -1);
118	assert(dev_buffer);	118	assert(dev_buffer);
119		119
120	b = malloc(sizeof(block_t));	120	b = malloc(sizeof(block_t));
121	if (!b)	121	if (!b)
122	return NULL;	122	return NULL;
123		123
124	b->data = malloc(bs);	124	b->data = malloc(bs);
125	if (!b->data) {	125	if (!b->data) {
126	free(b);	126	free(b);
127	return NULL;	127	return NULL;
128	}	128	}
129	b->size = bs;	129	b->size = bs;
130		130
131	if (!libfs_blockread(dev_phone, dev_buffer, &bufpos, &buflen, &pos,	131	if (!libfs_blockread(dev_phone, dev_buffer, &bufpos, &buflen, &pos,
132	b->data, bs, bs)) {	132	b->data, bs, bs)) {
133	free(b->data);	133	free(b->data);
134	free(b);	134	free(b);
135	return NULL;	135	return NULL;
136	}	136	}
137		137
138	return b;	138	return b;
139	}	139	}
140		140
141	static void block_put(block_t *block)	141	static void block_put(block_t *block)
142	{	142	{
143	/* FIXME */	143	/* FIXME */
144	free(block->data);	144	free(block->data);
145	free(block);	145	free(block);
146	}	146	}
147		147
148	#define FAT_BS(b) ((fat_bs_t *)((b)->data))	148	#define FAT_BS(b) ((fat_bs_t *)((b)->data))
149		149
150	#define FAT_CLST_RES0 0x0000	150	#define FAT_CLST_RES0 0x0000
151	#define FAT_CLST_RES1 0x0001	151	#define FAT_CLST_RES1 0x0001
152	#define FAT_CLST_FIRST 0x0002	152	#define FAT_CLST_FIRST 0x0002
153	#define FAT_CLST_BAD 0xfff7	153	#define FAT_CLST_BAD 0xfff7
154	#define FAT_CLST_LAST1 0xfff8	154	#define FAT_CLST_LAST1 0xfff8
155	#define FAT_CLST_LAST8 0xffff	155	#define FAT_CLST_LAST8 0xffff
156		156
157	/* internally used to mark root directory's parent */	157	/* internally used to mark root directory's parent */
158	#define FAT_CLST_ROOTPAR FAT_CLST_RES0	158	#define FAT_CLST_ROOTPAR FAT_CLST_RES0
159	/* internally used to mark root directory */	159	/* internally used to mark root directory */
160	#define FAT_CLST_ROOT FAT_CLST_RES1	160	#define FAT_CLST_ROOT FAT_CLST_RES1
161		161
162	#define fat_block_get(np, off) \	162	#define fat_block_get(np, off) \
163	_fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))	163	_fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))
164		164
165	static block_t *	165	static block_t *
166	_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)	166	_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)
167	{	167	{
168	block_t *bb;	168	block_t *bb;
169	block_t *b;	169	block_t *b;
170	unsigned bps;	170	unsigned bps;
171	unsigned spc;	171	unsigned spc;
172	unsigned rscnt; /* block address of the first FAT */	172	unsigned rscnt; /* block address of the first FAT */
173	unsigned fatcnt;	173	unsigned fatcnt;
174	unsigned rde;	174	unsigned rde;
175	unsigned rds; /* root directory size */	175	unsigned rds; /* root directory size */
176	unsigned sf;	176	unsigned sf;
177	unsigned ssa; /* size of the system area */	177	unsigned ssa; /* size of the system area */
178	unsigned clusters;	178	unsigned clusters;
179	fat_cluster_t clst = firstc;	179	fat_cluster_t clst = firstc;
180	unsigned i;	180	unsigned i;
181		181
182	bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);	182	bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);
183	bps = uint16_t_le2host(FAT_BS(bb)->bps);	183	bps = uint16_t_le2host(FAT_BS(bb)->bps);
184	spc = FAT_BS(bb)->spc;	184	spc = FAT_BS(bb)->spc;
185	rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);	185	rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
186	fatcnt = FAT_BS(bb)->fatcnt;	186	fatcnt = FAT_BS(bb)->fatcnt;
187	rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);	187	rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
188	sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);	188	sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);
189	block_put(bb);	189	block_put(bb);
190		190
191	rds = (sizeof(fat_dentry_t) * rde) / bps;	191	rds = (sizeof(fat_dentry_t) * rde) / bps;
192	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);	192	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
193	ssa = rscnt + fatcnt * sf + rds;	193	ssa = rscnt + fatcnt * sf + rds;
194		194
195	if (firstc == FAT_CLST_ROOT) {	195	if (firstc == FAT_CLST_ROOT) {
196	/* root directory special case */	196	/* root directory special case */
197	assert(offset < rds);	197	assert(offset < rds);
198	b = block_get(dev_handle, rscnt + fatcnt * sf + offset, bps);	198	b = block_get(dev_handle, rscnt + fatcnt * sf + offset, bps);
199	return b;	199	return b;
200	}	200	}
201		201
202	clusters = offset / spc;	202	clusters = offset / spc;
203	for (i = 0; i < clusters; i++) {	203	for (i = 0; i < clusters; i++) {
204	unsigned fsec; /* sector offset relative to FAT1 */	204	unsigned fsec; /* sector offset relative to FAT1 */
205	unsigned fidx; /* FAT1 entry index */	205	unsigned fidx; /* FAT1 entry index */
206		206
207	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);	207	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
208	fsec = (clst * sizeof(fat_cluster_t)) / bps;	208	fsec = (clst * sizeof(fat_cluster_t)) / bps;
209	fidx = clst % (bps / sizeof(fat_cluster_t));	209	fidx = clst % (bps / sizeof(fat_cluster_t));
210	/* read FAT1 */	210	/* read FAT1 */
211	b = block_get(dev_handle, rscnt + fsec, bps);	211	b = block_get(dev_handle, rscnt + fsec, bps);
212	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);	212	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
213	assert(clst != FAT_CLST_BAD);	213	assert(clst != FAT_CLST_BAD);
214	assert(clst < FAT_CLST_LAST1);	214	assert(clst < FAT_CLST_LAST1);
215	block_put(b);	215	block_put(b);
216	}	216	}
217		217
218	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +	218	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
219	offset % spc, bps);	219	offset % spc, bps);
220		220
221	return b;	221	return b;
222	}	222	}
223		223
224	static void fat_node_initialize(fat_node_t *node)	224	static void fat_node_initialize(fat_node_t *node)
225	{	225	{
226	futex_initialize(&node->lock, 1);	226	futex_initialize(&node->lock, 1);
227	node->idx = NULL;	227	node->idx = NULL;
228	node->type = 0;	228	node->type = 0;
229	link_initialize(&node->ffn_link);	229	link_initialize(&node->ffn_link);
230	node->size = 0;	230	node->size = 0;
231	node->lnkcnt = 0;	231	node->lnkcnt = 0;
232	node->refcnt = 0;	232	node->refcnt = 0;
233	node->dirty = false;	233	node->dirty = false;
234	}	234	}
235		235
236	static uint16_t fat_bps_get(dev_handle_t dev_handle)	236	static uint16_t fat_bps_get(dev_handle_t dev_handle)
237	{	237	{
238	block_t *bb;	238	block_t *bb;
239	uint16_t bps;	239	uint16_t bps;
240		240
241	bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);	241	bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);
242	assert(bb != NULL);	242	assert(bb != NULL);
243	bps = uint16_t_le2host(FAT_BS(bb)->bps);	243	bps = uint16_t_le2host(FAT_BS(bb)->bps);
244	block_put(bb);	244	block_put(bb);
245		245
246	return bps;	246	return bps;
247	}	247	}
248		248
249	typedef enum {	249	typedef enum {
250	FAT_DENTRY_SKIP,	250	FAT_DENTRY_SKIP,
251	FAT_DENTRY_LAST,	251	FAT_DENTRY_LAST,
252	FAT_DENTRY_VALID	252	FAT_DENTRY_VALID
253	} fat_dentry_clsf_t;	253	} fat_dentry_clsf_t;
254		254
255	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)	255	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)
256	{	256	{
257	if (d->attr & FAT_ATTR_VOLLABEL) {	257	if (d->attr & FAT_ATTR_VOLLABEL) {
258	/* volume label entry */	258	/* volume label entry */
259	return FAT_DENTRY_SKIP;	259	return FAT_DENTRY_SKIP;
260	}	260	}
261	if (d->name[0] == FAT_DENTRY_ERASED) {	261	if (d->name[0] == FAT_DENTRY_ERASED) {
262	/* not-currently-used entry */	262	/* not-currently-used entry */
263	return FAT_DENTRY_SKIP;	263	return FAT_DENTRY_SKIP;
264	}	264	}
265	if (d->name[0] == FAT_DENTRY_UNUSED) {	265	if (d->name[0] == FAT_DENTRY_UNUSED) {
266	/* never used entry */	266	/* never used entry */
267	return FAT_DENTRY_LAST;	267	return FAT_DENTRY_LAST;
268	}	268	}
269	if (d->name[0] == FAT_DENTRY_DOT) {	269	if (d->name[0] == FAT_DENTRY_DOT) {
270	/*	270	/*
271	* Most likely '.' or '..'.	271	* Most likely '.' or '..'.
272	* It cannot occur in a regular file name.	272	* It cannot occur in a regular file name.
273	*/	273	*/
274	return FAT_DENTRY_SKIP;	274	return FAT_DENTRY_SKIP;
275	}	275	}
276	return FAT_DENTRY_VALID;	276	return FAT_DENTRY_VALID;
277	}	277	}
278		278
279	static void fat_node_sync(fat_node_t *node)	279	static void fat_node_sync(fat_node_t *node)
280	{	280	{
281	/* TODO */	281	/* TODO */
282	}	282	}
283		283
284	/** Internal version of fat_node_get().	284	/** Internal version of fat_node_get().
285	*	285	*
286	* @param idxp Locked index structure.	286	* @param idxp Locked index structure.
287	*/	287	*/
288	static void fat_node_get_core(fat_idx_t idxp)	288	static void fat_node_get_core(fat_idx_t idxp)
289	{	289	{
290	block_t *b;	290	block_t *b;
291	fat_dentry_t *d;	291	fat_dentry_t *d;
292	fat_node_t *nodep;	292	fat_node_t *nodep;
293	unsigned bps;	293	unsigned bps;
294	unsigned dps;	294	unsigned dps;
295		295
296	if (idxp->nodep) {	296	if (idxp->nodep) {
297	/*	297	/*
298	* We are lucky.	298	* We are lucky.
299	* The node is already instantiated in memory.	299	* The node is already instantiated in memory.
300	*/	300	*/
301	futex_down(&idxp->nodep->lock);	301	futex_down(&idxp->nodep->lock);
302	if (!idxp->nodep->refcnt++)	302	if (!idxp->nodep->refcnt++)
303	list_remove(&nodep->ffn_link);	303	list_remove(&nodep->ffn_link);
304	futex_up(&idxp->nodep->lock);	304	futex_up(&idxp->nodep->lock);
305	return idxp->nodep;	305	return idxp->nodep;
306	}	306	}
307		307
308	/*	308	/*
309	* We must instantiate the node from the file system.	309	* We must instantiate the node from the file system.
310	*/	310	*/
311		311
312	assert(idxp->pfc);	312	assert(idxp->pfc);
313		313
314	futex_down(&ffn_futex);	314	futex_down(&ffn_futex);
315	if (!list_empty(&ffn_head)) {	315	if (!list_empty(&ffn_head)) {
316	/* Try to use a cached free node structure. */	316	/* Try to use a cached free node structure. */
317	fat_idx_t *idxp_tmp;	317	fat_idx_t *idxp_tmp;
318	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);	318	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
319	if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)	319	if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
320	goto skip_cache;	320	goto skip_cache;
321	idxp_tmp = nodep->idx;	321	idxp_tmp = nodep->idx;
322	if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {	322	if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
323	futex_up(&nodep->lock);	323	futex_up(&nodep->lock);
324	goto skip_cache;	324	goto skip_cache;
325	}	325	}
326	list_remove(&nodep->ffn_link);	326	list_remove(&nodep->ffn_link);
327	futex_up(&ffn_futex);	327	futex_up(&ffn_futex);
328	if (nodep->dirty)	328	if (nodep->dirty)
329	fat_node_sync(nodep);	329	fat_node_sync(nodep);
330	idxp_tmp->nodep = NULL;	330	idxp_tmp->nodep = NULL;
331	futex_up(&nodep->lock);	331	futex_up(&nodep->lock);
332	futex_up(&idxp_tmp->lock);	332	futex_up(&idxp_tmp->lock);
333	} else {	333	} else {
334	skip_cache:	334	skip_cache:
335	/* Try to allocate a new node structure. */	335	/* Try to allocate a new node structure. */
336	futex_up(&ffn_futex);	336	futex_up(&ffn_futex);
337	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));	337	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
338	if (!nodep)	338	if (!nodep)
339	return NULL;	339	return NULL;
340	}	340	}
341	fat_node_initialize(nodep);	341	fat_node_initialize(nodep);
342		342
343	bps = fat_bps_get(idxp->dev_handle);	343	bps = fat_bps_get(idxp->dev_handle);
344	dps = bps / sizeof(fat_dentry_t);	344	dps = bps / sizeof(fat_dentry_t);
345		345
346	/* Read the block that contains the dentry of interest. */	346	/* Read the block that contains the dentry of interest. */
347	b = _fat_block_get(idxp->dev_handle, idxp->pfc,	347	b = _fat_block_get(idxp->dev_handle, idxp->pfc,
348	(idxp->pdi * sizeof(fat_dentry_t)) / bps);	348	(idxp->pdi * sizeof(fat_dentry_t)) / bps);
349	assert(b);	349	assert(b);
350		350
351	d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);	351	d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
352	if (d->attr & FAT_ATTR_SUBDIR) {	352	if (d->attr & FAT_ATTR_SUBDIR) {
353	/*	353	/*
354	* The only directory which does not have this bit set is the	354	* The only directory which does not have this bit set is the
355	* root directory itself. The root directory node is handled	355	* root directory itself. The root directory node is handled
356	* and initialized elsewhere.	356	* and initialized elsewhere.
357	*/	357	*/
358	nodep->type = FAT_DIRECTORY;	358	nodep->type = FAT_DIRECTORY;
359	/*	359	/*
360	* TODO: determine the size by walking FAT. Surprisingly, the	360	* TODO: determine the size by walking FAT. Surprisingly, the
361	* 'size' filed of the FAT dentry is not defined for the	361	* 'size' filed of the FAT dentry is not defined for the
362	* directory entry type.	362	* directory entry type.
363	*/	363	*/
364	nodep->size = 64 * sizeof(fat_dentry_t);	364	nodep->size = 64 * sizeof(fat_dentry_t);
365	} else {	365	} else {
366	nodep->type = FAT_FILE;	366	nodep->type = FAT_FILE;
367	nodep->size = uint32_t_le2host(d->size);	367	nodep->size = uint32_t_le2host(d->size);
368	}	368	}
369	nodep->firstc = uint16_t_le2host(d->firstc);	369	nodep->firstc = uint16_t_le2host(d->firstc);
370	nodep->lnkcnt = 1;	370	nodep->lnkcnt = 1;
371	nodep->refcnt = 1;	371	nodep->refcnt = 1;
372		372
373	block_put(b);	373	block_put(b);
374		374
375	/* Link the idx structure with the node structure. */	375	/* Link the idx structure with the node structure. */
376	nodep->idx = idxp;	376	nodep->idx = idxp;
377	idxp->nodep = nodep;	377	idxp->nodep = nodep;
378		378
379	return nodep;	379	return nodep;
380	}	380	}
381		381
382	/** Instantiate a FAT in-core node. */	382	/** Instantiate a FAT in-core node. */
383	static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)	383	static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
384	{	384	{
385	void *node;	385	void *node;
386	fat_idx_t *idxp;	386	fat_idx_t *idxp;
387		387
388	idxp = fat_idx_get_by_index(dev_handle, index);	388	idxp = fat_idx_get_by_index(dev_handle, index);
389	if (!idxp)	389	if (!idxp)
390	return NULL;	390	return NULL;
391	/* idxp->lock held */	391	/* idxp->lock held */
392	node = fat_node_get_core(idxp);	392	node = fat_node_get_core(idxp);
393	futex_up(&idxp->lock);	393	futex_up(&idxp->lock);
394	return node;	394	return node;
395	}	395	}
396		396
397	static void fat_node_put(void *node)	397	static void fat_node_put(void *node)
398	{	398	{
399	fat_node_t nodep = (fat_node_t )node;	399	fat_node_t nodep = (fat_node_t )node;
400		400
401	futex_down(&nodep->lock);	401	futex_down(&nodep->lock);
402	if (!--nodep->refcnt) {	402	if (!--nodep->refcnt) {
403	futex_down(&ffn_futex);	403	futex_down(&ffn_futex);
404	list_append(&nodep->ffn_link, &ffn_head);	404	list_append(&nodep->ffn_link, &ffn_head);
405	futex_up(&ffn_futex);	405	futex_up(&ffn_futex);
406	}	406	}
407	futex_up(&nodep->lock);	407	futex_up(&nodep->lock);
408	}	408	}
409		409
410	static void *fat_create(int flags)	410	static void *fat_create(int flags)
411	{	411	{
412	return NULL; /* not supported at the moment */	412	return NULL; /* not supported at the moment */
413	}	413	}
414		414
415	static int fat_destroy(void *node)	415	static int fat_destroy(void *node)
416	{	416	{
417	return ENOTSUP; /* not supported at the moment */	417	return ENOTSUP; /* not supported at the moment */
418	}	418	}
419		419
420	static bool fat_link(void prnt, void chld, const char *name)	420	static bool fat_link(void prnt, void chld, const char *name)
421	{	421	{
422	return false; /* not supported at the moment */	422	return false; /* not supported at the moment */
423	}	423	}
424		424
425	static int fat_unlink(void prnt, void chld)	425	static int fat_unlink(void prnt, void chld)
426	{	426	{
427	return ENOTSUP; /* not supported at the moment */	427	return ENOTSUP; /* not supported at the moment */
428	}	428	}
429		429
430	static void fat_match(void prnt, const char *component)	430	static void fat_match(void prnt, const char *component)
431	{	431	{
432	fat_node_t parentp = (fat_node_t )prnt;	432	fat_node_t parentp = (fat_node_t )prnt;
433	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];	433	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
434	unsigned i, j;	434	unsigned i, j;
435	unsigned bps; /* bytes per sector */	435	unsigned bps; /* bytes per sector */
436	unsigned dps; /* dentries per sector */	436	unsigned dps; /* dentries per sector */
437	unsigned blocks;	437	unsigned blocks;
438	fat_dentry_t *d;	438	fat_dentry_t *d;
439	block_t *b;	439	block_t *b;
440		440
441	futex_down(&parentp->idx->lock);	441	futex_down(&parentp->idx->lock);
442	bps = fat_bps_get(parentp->idx->dev_handle);	442	bps = fat_bps_get(parentp->idx->dev_handle);
443	dps = bps / sizeof(fat_dentry_t);	443	dps = bps / sizeof(fat_dentry_t);
444	blocks = parentp->size / bps + (parentp->size % bps != 0);	444	blocks = parentp->size / bps + (parentp->size % bps != 0);
445	for (i = 0; i < blocks; i++) {	445	for (i = 0; i < blocks; i++) {
446	unsigned dentries;	446	unsigned dentries;
447		447
448	b = fat_block_get(parentp, i);	448	b = fat_block_get(parentp, i);
449	dentries = (i == blocks - 1) ?	449	dentries = (i == blocks - 1) ?
450	parentp->size % sizeof(fat_dentry_t) :	450	parentp->size % sizeof(fat_dentry_t) :
451	dps;	451	dps;
452	for (j = 0; j < dentries; j++) {	452	for (j = 0; j < dentries; j++) {
453	d = ((fat_dentry_t *)b->data) + j;	453	d = ((fat_dentry_t *)b->data) + j;
454	switch (fat_classify_dentry(d)) {	454	switch (fat_classify_dentry(d)) {
455	case FAT_DENTRY_SKIP:	455	case FAT_DENTRY_SKIP:
456	continue;	456	continue;
457	case FAT_DENTRY_LAST:	457	case FAT_DENTRY_LAST:
458	block_put(b);	458	block_put(b);
459	futex_up(&parentp->idx->lock);	459	futex_up(&parentp->idx->lock);
460	return NULL;	460	return NULL;
461	default:	461	default:
462	case FAT_DENTRY_VALID:	462	case FAT_DENTRY_VALID:
463	dentry_name_canonify(d, name);	463	dentry_name_canonify(d, name);
464	break;	464	break;
465	}	465	}
466	if (stricmp(name, component) == 0) {	466	if (stricmp(name, component) == 0) {
467	/* hit */	467	/* hit */
468	void *node;	468	void *node;
469	/*	469	/*
470	* Assume tree hierarchy for locking. We	470	* Assume tree hierarchy for locking. We
471	* already have the parent and now we are going	471	* already have the parent and now we are going
472	* to lock the child. Never lock in the oposite	472	* to lock the child. Never lock in the oposite
473	* order.	473	* order.
474	*/	474	*/
475	fat_idx_t *idx = fat_idx_get_by_pos(	475	fat_idx_t *idx = fat_idx_get_by_pos(
476	parentp->idx->dev_handle, parentp->firstc,	476	parentp->idx->dev_handle, parentp->firstc,
477	i * dps + j);	477	i * dps + j);
478	futex_up(&parentp->idx->lock);	478	futex_up(&parentp->idx->lock);
479	if (!idx) {	479	if (!idx) {
480	/*	480	/*
481	* Can happen if memory is low or if we	481	* Can happen if memory is low or if we
482	* run out of 32-bit indices.	482	* run out of 32-bit indices.
483	*/	483	*/
484	block_put(b);	484	block_put(b);
485	return NULL;	485	return NULL;
486	}	486	}
487	node = fat_node_get_core(idx);	487	node = fat_node_get_core(idx);
488	futex_up(&idx->lock);	488	futex_up(&idx->lock);
489	block_put(b);	489	block_put(b);
490	return node;	490	return node;
491	}	491	}
492	}	492	}
493	block_put(b);	493	block_put(b);
494	}	494	}
495	futex_up(&parentp->idx->lock);	495	futex_up(&parentp->idx->lock);
496	return NULL;	496	return NULL;
497	}	497	}
498		498
499	static fs_index_t fat_index_get(void *node)	499	static fs_index_t fat_index_get(void *node)
500	{	500	{

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/fs/fat/fat_ops.c – Rev 3282 → 3307