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
 
#define min(a, b)       ((a) < (b) ? (a) : (b))
 
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 = NULL;
    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(&idxp->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);
    uint16_t bps = fat_bps_get(dev_handle);
    size_t bytes;
 
    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) {
        block_t *b;
 
        bytes = min(len, bps - pos % bps);
        b = fat_block_get(nodep, pos / bps);
        (void) ipc_data_read_finalize(callid, b->data + pos % bps,
            bytes);
        block_put(b);
    } 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);
    ipc_answer_1(rid, EOK, (ipcarg_t)bytes);
}
 
/**
 * @}
 */
 

Rev 3308	Rev 3312
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	#define min(a, b) ((a) < (b) ? (a) : (b))	73	#define min(a, b) ((a) < (b) ? (a) : (b))
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	break;	81	break;
82	if (d->name[i] == FAT_DENTRY_E5_ESC)	82	if (d->name[i] == FAT_DENTRY_E5_ESC)
83	*buf++ = 0xe5;	83	*buf++ = 0xe5;
84	else	84	else
85	*buf++ = d->name[i];	85	*buf++ = d->name[i];
86	}	86	}
87	if (d->ext[0] != FAT_PAD)	87	if (d->ext[0] != FAT_PAD)
88	*buf++ = '.';	88	*buf++ = '.';
89	for (i = 0; i < FAT_EXT_LEN; i++) {	89	for (i = 0; i < FAT_EXT_LEN; i++) {
90	if (d->ext[i] == FAT_PAD) {	90	if (d->ext[i] == FAT_PAD) {
91	*buf = '\0';	91	*buf = '\0';
92	return;	92	return;
93	}	93	}
94	if (d->ext[i] == FAT_DENTRY_E5_ESC)	94	if (d->ext[i] == FAT_DENTRY_E5_ESC)
95	*buf++ = 0xe5;	95	*buf++ = 0xe5;
96	else	96	else
97	*buf++ = d->ext[i];	97	*buf++ = d->ext[i];
98	}	98	}
99	*buf = '\0';	99	*buf = '\0';
100	}	100	}
101		101
102	static int dev_phone = -1; /* FIXME */	102	static int dev_phone = -1; /* FIXME */
103	static void dev_buffer = NULL; / FIXME */	103	static void dev_buffer = NULL; / FIXME */
104		104
105	/* TODO move somewhere else */	105	/* TODO move somewhere else */
106	typedef struct {	106	typedef struct {
107	void *data;	107	void *data;
108	size_t size;	108	size_t size;
109	} block_t;	109	} block_t;
110		110
111	static block_t *block_get(dev_handle_t dev_handle, off_t offset, size_t bs)	111	static block_t *block_get(dev_handle_t dev_handle, off_t offset, size_t bs)
112	{	112	{
113	/* FIXME */	113	/* FIXME */
114	block_t *b;	114	block_t *b;
115	off_t bufpos = 0;	115	off_t bufpos = 0;
116	size_t buflen = 0;	116	size_t buflen = 0;
117	off_t pos = offset * bs;	117	off_t pos = offset * bs;
118		118
119	assert(dev_phone != -1);	119	assert(dev_phone != -1);
120	assert(dev_buffer);	120	assert(dev_buffer);
121		121
122	b = malloc(sizeof(block_t));	122	b = malloc(sizeof(block_t));
123	if (!b)	123	if (!b)
124	return NULL;	124	return NULL;
125		125
126	b->data = malloc(bs);	126	b->data = malloc(bs);
127	if (!b->data) {	127	if (!b->data) {
128	free(b);	128	free(b);
129	return NULL;	129	return NULL;
130	}	130	}
131	b->size = bs;	131	b->size = bs;
132		132
133	if (!libfs_blockread(dev_phone, dev_buffer, &bufpos, &buflen, &pos,	133	if (!libfs_blockread(dev_phone, dev_buffer, &bufpos, &buflen, &pos,
134	b->data, bs, bs)) {	134	b->data, bs, bs)) {
135	free(b->data);	135	free(b->data);
136	free(b);	136	free(b);
137	return NULL;	137	return NULL;
138	}	138	}
139		139
140	return b;	140	return b;
141	}	141	}
142		142
143	static void block_put(block_t *block)	143	static void block_put(block_t *block)
144	{	144	{
145	/* FIXME */	145	/* FIXME */
146	free(block->data);	146	free(block->data);
147	free(block);	147	free(block);
148	}	148	}
149		149
150	#define FAT_BS(b) ((fat_bs_t *)((b)->data))	150	#define FAT_BS(b) ((fat_bs_t *)((b)->data))
151		151
152	#define FAT_CLST_RES0 0x0000	152	#define FAT_CLST_RES0 0x0000
153	#define FAT_CLST_RES1 0x0001	153	#define FAT_CLST_RES1 0x0001
154	#define FAT_CLST_FIRST 0x0002	154	#define FAT_CLST_FIRST 0x0002
155	#define FAT_CLST_BAD 0xfff7	155	#define FAT_CLST_BAD 0xfff7
156	#define FAT_CLST_LAST1 0xfff8	156	#define FAT_CLST_LAST1 0xfff8
157	#define FAT_CLST_LAST8 0xffff	157	#define FAT_CLST_LAST8 0xffff
158		158
159	/* internally used to mark root directory's parent */	159	/* internally used to mark root directory's parent */
160	#define FAT_CLST_ROOTPAR FAT_CLST_RES0	160	#define FAT_CLST_ROOTPAR FAT_CLST_RES0
161	/* internally used to mark root directory */	161	/* internally used to mark root directory */
162	#define FAT_CLST_ROOT FAT_CLST_RES1	162	#define FAT_CLST_ROOT FAT_CLST_RES1
163		163
164	#define fat_block_get(np, off) \	164	#define fat_block_get(np, off) \
165	_fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))	165	_fat_block_get((np)->idx->dev_handle, (np)->firstc, (off))
166		166
167	static block_t *	167	static block_t *
168	_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)	168	_fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset)
169	{	169	{
170	block_t *bb;	170	block_t *bb;
171	block_t *b;	171	block_t *b;
172	unsigned bps;	172	unsigned bps;
173	unsigned spc;	173	unsigned spc;
174	unsigned rscnt; /* block address of the first FAT */	174	unsigned rscnt; /* block address of the first FAT */
175	unsigned fatcnt;	175	unsigned fatcnt;
176	unsigned rde;	176	unsigned rde;
177	unsigned rds; /* root directory size */	177	unsigned rds; /* root directory size */
178	unsigned sf;	178	unsigned sf;
179	unsigned ssa; /* size of the system area */	179	unsigned ssa; /* size of the system area */
180	unsigned clusters;	180	unsigned clusters;
181	fat_cluster_t clst = firstc;	181	fat_cluster_t clst = firstc;
182	unsigned i;	182	unsigned i;
183		183
184	bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);	184	bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);
185	bps = uint16_t_le2host(FAT_BS(bb)->bps);	185	bps = uint16_t_le2host(FAT_BS(bb)->bps);
186	spc = FAT_BS(bb)->spc;	186	spc = FAT_BS(bb)->spc;
187	rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);	187	rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt);
188	fatcnt = FAT_BS(bb)->fatcnt;	188	fatcnt = FAT_BS(bb)->fatcnt;
189	rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);	189	rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max);
190	sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);	190	sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat);
191	block_put(bb);	191	block_put(bb);
192		192
193	rds = (sizeof(fat_dentry_t) * rde) / bps;	193	rds = (sizeof(fat_dentry_t) * rde) / bps;
194	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);	194	rds += ((sizeof(fat_dentry_t) * rde) % bps != 0);
195	ssa = rscnt + fatcnt * sf + rds;	195	ssa = rscnt + fatcnt * sf + rds;
196		196
197	if (firstc == FAT_CLST_ROOT) {	197	if (firstc == FAT_CLST_ROOT) {
198	/* root directory special case */	198	/* root directory special case */
199	assert(offset < rds);	199	assert(offset < rds);
200	b = block_get(dev_handle, rscnt + fatcnt * sf + offset, bps);	200	b = block_get(dev_handle, rscnt + fatcnt * sf + offset, bps);
201	return b;	201	return b;
202	}	202	}
203		203
204	clusters = offset / spc;	204	clusters = offset / spc;
205	for (i = 0; i < clusters; i++) {	205	for (i = 0; i < clusters; i++) {
206	unsigned fsec; /* sector offset relative to FAT1 */	206	unsigned fsec; /* sector offset relative to FAT1 */
207	unsigned fidx; /* FAT1 entry index */	207	unsigned fidx; /* FAT1 entry index */
208		208
209	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);	209	assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD);
210	fsec = (clst * sizeof(fat_cluster_t)) / bps;	210	fsec = (clst * sizeof(fat_cluster_t)) / bps;
211	fidx = clst % (bps / sizeof(fat_cluster_t));	211	fidx = clst % (bps / sizeof(fat_cluster_t));
212	/* read FAT1 */	212	/* read FAT1 */
213	b = block_get(dev_handle, rscnt + fsec, bps);	213	b = block_get(dev_handle, rscnt + fsec, bps);
214	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);	214	clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]);
215	assert(clst != FAT_CLST_BAD);	215	assert(clst != FAT_CLST_BAD);
216	assert(clst < FAT_CLST_LAST1);	216	assert(clst < FAT_CLST_LAST1);
217	block_put(b);	217	block_put(b);
218	}	218	}
219		219
220	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +	220	b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc +
221	offset % spc, bps);	221	offset % spc, bps);
222		222
223	return b;	223	return b;
224	}	224	}
225		225
226	static void fat_node_initialize(fat_node_t *node)	226	static void fat_node_initialize(fat_node_t *node)
227	{	227	{
228	futex_initialize(&node->lock, 1);	228	futex_initialize(&node->lock, 1);
229	node->idx = NULL;	229	node->idx = NULL;
230	node->type = 0;	230	node->type = 0;
231	link_initialize(&node->ffn_link);	231	link_initialize(&node->ffn_link);
232	node->size = 0;	232	node->size = 0;
233	node->lnkcnt = 0;	233	node->lnkcnt = 0;
234	node->refcnt = 0;	234	node->refcnt = 0;
235	node->dirty = false;	235	node->dirty = false;
236	}	236	}
237		237
238	static uint16_t fat_bps_get(dev_handle_t dev_handle)	238	static uint16_t fat_bps_get(dev_handle_t dev_handle)
239	{	239	{
240	block_t *bb;	240	block_t *bb;
241	uint16_t bps;	241	uint16_t bps;
242		242
243	bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);	243	bb = block_get(dev_handle, BS_BLOCK, BS_SIZE);
244	assert(bb != NULL);	244	assert(bb != NULL);
245	bps = uint16_t_le2host(FAT_BS(bb)->bps);	245	bps = uint16_t_le2host(FAT_BS(bb)->bps);
246	block_put(bb);	246	block_put(bb);
247		247
248	return bps;	248	return bps;
249	}	249	}
250		250
251	typedef enum {	251	typedef enum {
252	FAT_DENTRY_SKIP,	252	FAT_DENTRY_SKIP,
253	FAT_DENTRY_LAST,	253	FAT_DENTRY_LAST,
254	FAT_DENTRY_VALID	254	FAT_DENTRY_VALID
255	} fat_dentry_clsf_t;	255	} fat_dentry_clsf_t;
256		256
257	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)	257	static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d)
258	{	258	{
259	if (d->attr & FAT_ATTR_VOLLABEL) {	259	if (d->attr & FAT_ATTR_VOLLABEL) {
260	/* volume label entry */	260	/* volume label entry */
261	return FAT_DENTRY_SKIP;	261	return FAT_DENTRY_SKIP;
262	}	262	}
263	if (d->name[0] == FAT_DENTRY_ERASED) {	263	if (d->name[0] == FAT_DENTRY_ERASED) {
264	/* not-currently-used entry */	264	/* not-currently-used entry */
265	return FAT_DENTRY_SKIP;	265	return FAT_DENTRY_SKIP;
266	}	266	}
267	if (d->name[0] == FAT_DENTRY_UNUSED) {	267	if (d->name[0] == FAT_DENTRY_UNUSED) {
268	/* never used entry */	268	/* never used entry */
269	return FAT_DENTRY_LAST;	269	return FAT_DENTRY_LAST;
270	}	270	}
271	if (d->name[0] == FAT_DENTRY_DOT) {	271	if (d->name[0] == FAT_DENTRY_DOT) {
272	/*	272	/*
273	* Most likely '.' or '..'.	273	* Most likely '.' or '..'.
274	* It cannot occur in a regular file name.	274	* It cannot occur in a regular file name.
275	*/	275	*/
276	return FAT_DENTRY_SKIP;	276	return FAT_DENTRY_SKIP;
277	}	277	}
278	return FAT_DENTRY_VALID;	278	return FAT_DENTRY_VALID;
279	}	279	}
280		280
281	static void fat_node_sync(fat_node_t *node)	281	static void fat_node_sync(fat_node_t *node)
282	{	282	{
283	/* TODO */	283	/* TODO */
284	}	284	}
285		285
286	/** Internal version of fat_node_get().	286	/** Internal version of fat_node_get().
287	*	287	*
288	* @param idxp Locked index structure.	288	* @param idxp Locked index structure.
289	*/	289	*/
290	static void fat_node_get_core(fat_idx_t idxp)	290	static void fat_node_get_core(fat_idx_t idxp)
291	{	291	{
292	block_t *b;	292	block_t *b;
293	fat_dentry_t *d;	293	fat_dentry_t *d;
294	fat_node_t *nodep;	294	fat_node_t *nodep = NULL;
295	unsigned bps;	295	unsigned bps;
296	unsigned dps;	296	unsigned dps;
297		297
298	if (idxp->nodep) {	298	if (idxp->nodep) {
299	/*	299	/*
300	* We are lucky.	300	* We are lucky.
301	* The node is already instantiated in memory.	301	* The node is already instantiated in memory.
302	*/	302	*/
303	futex_down(&idxp->nodep->lock);	303	futex_down(&idxp->nodep->lock);
304	if (!idxp->nodep->refcnt++)	304	if (!idxp->nodep->refcnt++)
305	list_remove(&nodep->ffn_link);	305	list_remove(&idxp->nodep->ffn_link);
306	futex_up(&idxp->nodep->lock);	306	futex_up(&idxp->nodep->lock);
307	return idxp->nodep;	307	return idxp->nodep;
308	}	308	}
309		309
310	/*	310	/*
311	* We must instantiate the node from the file system.	311	* We must instantiate the node from the file system.
312	*/	312	*/
313		313
314	assert(idxp->pfc);	314	assert(idxp->pfc);
315		315
316	futex_down(&ffn_futex);	316	futex_down(&ffn_futex);
317	if (!list_empty(&ffn_head)) {	317	if (!list_empty(&ffn_head)) {
318	/* Try to use a cached free node structure. */	318	/* Try to use a cached free node structure. */
319	fat_idx_t *idxp_tmp;	319	fat_idx_t *idxp_tmp;
320	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);	320	nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link);
321	if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)	321	if (futex_trydown(&nodep->lock) == ESYNCH_WOULD_BLOCK)
322	goto skip_cache;	322	goto skip_cache;
323	idxp_tmp = nodep->idx;	323	idxp_tmp = nodep->idx;
324	if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {	324	if (futex_trydown(&idxp_tmp->lock) == ESYNCH_WOULD_BLOCK) {
325	futex_up(&nodep->lock);	325	futex_up(&nodep->lock);
326	goto skip_cache;	326	goto skip_cache;
327	}	327	}
328	list_remove(&nodep->ffn_link);	328	list_remove(&nodep->ffn_link);
329	futex_up(&ffn_futex);	329	futex_up(&ffn_futex);
330	if (nodep->dirty)	330	if (nodep->dirty)
331	fat_node_sync(nodep);	331	fat_node_sync(nodep);
332	idxp_tmp->nodep = NULL;	332	idxp_tmp->nodep = NULL;
333	futex_up(&nodep->lock);	333	futex_up(&nodep->lock);
334	futex_up(&idxp_tmp->lock);	334	futex_up(&idxp_tmp->lock);
335	} else {	335	} else {
336	skip_cache:	336	skip_cache:
337	/* Try to allocate a new node structure. */	337	/* Try to allocate a new node structure. */
338	futex_up(&ffn_futex);	338	futex_up(&ffn_futex);
339	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));	339	nodep = (fat_node_t *)malloc(sizeof(fat_node_t));
340	if (!nodep)	340	if (!nodep)
341	return NULL;	341	return NULL;
342	}	342	}
343	fat_node_initialize(nodep);	343	fat_node_initialize(nodep);
344		344
345	bps = fat_bps_get(idxp->dev_handle);	345	bps = fat_bps_get(idxp->dev_handle);
346	dps = bps / sizeof(fat_dentry_t);	346	dps = bps / sizeof(fat_dentry_t);
347		347
348	/* Read the block that contains the dentry of interest. */	348	/* Read the block that contains the dentry of interest. */
349	b = _fat_block_get(idxp->dev_handle, idxp->pfc,	349	b = _fat_block_get(idxp->dev_handle, idxp->pfc,
350	(idxp->pdi * sizeof(fat_dentry_t)) / bps);	350	(idxp->pdi * sizeof(fat_dentry_t)) / bps);
351	assert(b);	351	assert(b);
352		352
353	d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);	353	d = ((fat_dentry_t *)b->data) + (idxp->pdi % dps);
354	if (d->attr & FAT_ATTR_SUBDIR) {	354	if (d->attr & FAT_ATTR_SUBDIR) {
355	/*	355	/*
356	* The only directory which does not have this bit set is the	356	* The only directory which does not have this bit set is the
357	* root directory itself. The root directory node is handled	357	* root directory itself. The root directory node is handled
358	* and initialized elsewhere.	358	* and initialized elsewhere.
359	*/	359	*/
360	nodep->type = FAT_DIRECTORY;	360	nodep->type = FAT_DIRECTORY;
361	/*	361	/*
362	* TODO: determine the size by walking FAT. Surprisingly, the	362	* TODO: determine the size by walking FAT. Surprisingly, the
363	* 'size' filed of the FAT dentry is not defined for the	363	* 'size' filed of the FAT dentry is not defined for the
364	* directory entry type.	364	* directory entry type.
365	*/	365	*/
366	nodep->size = 64 * sizeof(fat_dentry_t);	366	nodep->size = 64 * sizeof(fat_dentry_t);
367	} else {	367	} else {
368	nodep->type = FAT_FILE;	368	nodep->type = FAT_FILE;
369	nodep->size = uint32_t_le2host(d->size);	369	nodep->size = uint32_t_le2host(d->size);
370	}	370	}
371	nodep->firstc = uint16_t_le2host(d->firstc);	371	nodep->firstc = uint16_t_le2host(d->firstc);
372	nodep->lnkcnt = 1;	372	nodep->lnkcnt = 1;
373	nodep->refcnt = 1;	373	nodep->refcnt = 1;
374		374
375	block_put(b);	375	block_put(b);
376		376
377	/* Link the idx structure with the node structure. */	377	/* Link the idx structure with the node structure. */
378	nodep->idx = idxp;	378	nodep->idx = idxp;
379	idxp->nodep = nodep;	379	idxp->nodep = nodep;
380		380
381	return nodep;	381	return nodep;
382	}	382	}
383		383
384	/** Instantiate a FAT in-core node. */	384	/** Instantiate a FAT in-core node. */
385	static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)	385	static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
386	{	386	{
387	void *node;	387	void *node;
388	fat_idx_t *idxp;	388	fat_idx_t *idxp;
389		389
390	idxp = fat_idx_get_by_index(dev_handle, index);	390	idxp = fat_idx_get_by_index(dev_handle, index);
391	if (!idxp)	391	if (!idxp)
392	return NULL;	392	return NULL;
393	/* idxp->lock held */	393	/* idxp->lock held */
394	node = fat_node_get_core(idxp);	394	node = fat_node_get_core(idxp);
395	futex_up(&idxp->lock);	395	futex_up(&idxp->lock);
396	return node;	396	return node;
397	}	397	}
398		398
399	static void fat_node_put(void *node)	399	static void fat_node_put(void *node)
400	{	400	{
401	fat_node_t nodep = (fat_node_t )node;	401	fat_node_t nodep = (fat_node_t )node;
402		402
403	futex_down(&nodep->lock);	403	futex_down(&nodep->lock);
404	if (!--nodep->refcnt) {	404	if (!--nodep->refcnt) {
405	futex_down(&ffn_futex);	405	futex_down(&ffn_futex);
406	list_append(&nodep->ffn_link, &ffn_head);	406	list_append(&nodep->ffn_link, &ffn_head);
407	futex_up(&ffn_futex);	407	futex_up(&ffn_futex);
408	}	408	}
409	futex_up(&nodep->lock);	409	futex_up(&nodep->lock);
410	}	410	}
411		411
412	static void *fat_create(int flags)	412	static void *fat_create(int flags)
413	{	413	{
414	return NULL; /* not supported at the moment */	414	return NULL; /* not supported at the moment */
415	}	415	}
416		416
417	static int fat_destroy(void *node)	417	static int fat_destroy(void *node)
418	{	418	{
419	return ENOTSUP; /* not supported at the moment */	419	return ENOTSUP; /* not supported at the moment */
420	}	420	}
421		421
422	static bool fat_link(void prnt, void chld, const char *name)	422	static bool fat_link(void prnt, void chld, const char *name)
423	{	423	{
424	return false; /* not supported at the moment */	424	return false; /* not supported at the moment */
425	}	425	}
426		426
427	static int fat_unlink(void prnt, void chld)	427	static int fat_unlink(void prnt, void chld)
428	{	428	{
429	return ENOTSUP; /* not supported at the moment */	429	return ENOTSUP; /* not supported at the moment */
430	}	430	}
431		431
432	static void fat_match(void prnt, const char *component)	432	static void fat_match(void prnt, const char *component)
433	{	433	{
434	fat_node_t parentp = (fat_node_t )prnt;	434	fat_node_t parentp = (fat_node_t )prnt;
435	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];	435	char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
436	unsigned i, j;	436	unsigned i, j;
437	unsigned bps; /* bytes per sector */	437	unsigned bps; /* bytes per sector */
438	unsigned dps; /* dentries per sector */	438	unsigned dps; /* dentries per sector */
439	unsigned blocks;	439	unsigned blocks;
440	fat_dentry_t *d;	440	fat_dentry_t *d;
441	block_t *b;	441	block_t *b;
442		442
443	futex_down(&parentp->idx->lock);	443	futex_down(&parentp->idx->lock);
444	bps = fat_bps_get(parentp->idx->dev_handle);	444	bps = fat_bps_get(parentp->idx->dev_handle);
445	dps = bps / sizeof(fat_dentry_t);	445	dps = bps / sizeof(fat_dentry_t);
446	blocks = parentp->size / bps + (parentp->size % bps != 0);	446	blocks = parentp->size / bps + (parentp->size % bps != 0);
447	for (i = 0; i < blocks; i++) {	447	for (i = 0; i < blocks; i++) {
448	unsigned dentries;	448	unsigned dentries;
449		449
450	b = fat_block_get(parentp, i);	450	b = fat_block_get(parentp, i);
451	dentries = (i == blocks - 1) ?	451	dentries = (i == blocks - 1) ?
452	parentp->size % sizeof(fat_dentry_t) :	452	parentp->size % sizeof(fat_dentry_t) :
453	dps;	453	dps;
454	for (j = 0; j < dentries; j++) {	454	for (j = 0; j < dentries; j++) {
455	d = ((fat_dentry_t *)b->data) + j;	455	d = ((fat_dentry_t *)b->data) + j;
456	switch (fat_classify_dentry(d)) {	456	switch (fat_classify_dentry(d)) {
457	case FAT_DENTRY_SKIP:	457	case FAT_DENTRY_SKIP:
458	continue;	458	continue;
459	case FAT_DENTRY_LAST:	459	case FAT_DENTRY_LAST:
460	block_put(b);	460	block_put(b);
461	futex_up(&parentp->idx->lock);	461	futex_up(&parentp->idx->lock);
462	return NULL;	462	return NULL;
463	default:	463	default:
464	case FAT_DENTRY_VALID:	464	case FAT_DENTRY_VALID:
465	dentry_name_canonify(d, name);	465	dentry_name_canonify(d, name);
466	break;	466	break;
467	}	467	}
468	if (stricmp(name, component) == 0) {	468	if (stricmp(name, component) == 0) {
469	/* hit */	469	/* hit */
470	void *node;	470	void *node;
471	/*	471	/*
472	* Assume tree hierarchy for locking. We	472	* Assume tree hierarchy for locking. We
473	* already have the parent and now we are going	473	* already have the parent and now we are going
474	* to lock the child. Never lock in the oposite	474	* to lock the child. Never lock in the oposite
475	* order.	475	* order.
476	*/	476	*/
477	fat_idx_t *idx = fat_idx_get_by_pos(	477	fat_idx_t *idx = fat_idx_get_by_pos(
478	parentp->idx->dev_handle, parentp->firstc,	478	parentp->idx->dev_handle, parentp->firstc,
479	i * dps + j);	479	i * dps + j);
480	futex_up(&parentp->idx->lock);	480	futex_up(&parentp->idx->lock);
481	if (!idx) {	481	if (!idx) {
482	/*	482	/*
483	* Can happen if memory is low or if we	483	* Can happen if memory is low or if we
484	* run out of 32-bit indices.	484	* run out of 32-bit indices.
485	*/	485	*/
486	block_put(b);	486	block_put(b);
487	return NULL;	487	return NULL;
488	}	488	}
489	node = fat_node_get_core(idx);	489	node = fat_node_get_core(idx);
490	futex_up(&idx->lock);	490	futex_up(&idx->lock);
491	block_put(b);	491	block_put(b);
492	return node;	492	return node;
493	}	493	}
494	}	494	}
495	block_put(b);	495	block_put(b);
496	}	496	}
497	futex_up(&parentp->idx->lock);	497	futex_up(&parentp->idx->lock);
498	return NULL;	498	return NULL;
499	}	499	}
500		500

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/fs/fat/fat_ops.c – Rev 3308 → 3312