| 0,0 → 1,516 |
|---|
| /* |
| * Copyright (c) 2008 Jakub Jermar |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /** @addtogroup fs |
| * @{ |
| */ |
| |
| /** |
| * @file fat_ops.c |
| * @brief Implementation of VFS operations for the FAT file system server. |
| */ |
| |
| #include "fat.h" |
| #include "../../vfs/vfs.h" |
| #include <libfs.h> |
| #include <ipc/ipc.h> |
| #include <async.h> |
| #include <errno.h> |
| #include <string.h> |
| #include <byteorder.h> |
| #include <libadt/hash_table.h> |
| #include <libadt/list.h> |
| #include <assert.h> |
| #include <futex.h> |
| |
| #define BS_BLOCK 0 |
| |
| /** List of free FAT nodes that still contain valid data. */ |
| LIST_INITIALIZE(ffn_head); |
| |
| #define FAT_NAME_LEN 8 |
| #define FAT_EXT_LEN 3 |
| |
| #define FAT_PAD ' ' |
| |
| #define FAT_DENTRY_UNUSED 0x00 |
| #define FAT_DENTRY_E5_ESC 0x05 |
| #define FAT_DENTRY_DOT 0x2e |
| #define FAT_DENTRY_ERASED 0xe5 |
| |
| static void dentry_name_canonify(fat_dentry_t *d, char *buf) |
| { |
| int i; |
| |
| for (i = 0; i < FAT_NAME_LEN; i++) { |
| if (d->name[i] == FAT_PAD) { |
| buf++; |
| break; |
| } |
| if (d->name[i] == FAT_DENTRY_E5_ESC) |
| *buf++ = 0xe5; |
| else |
| *buf++ = d->name[i]; |
| } |
| if (d->ext[0] != FAT_PAD) |
| *buf++ = '.'; |
| for (i = 0; i < FAT_EXT_LEN; i++) { |
| if (d->ext[i] == FAT_PAD) { |
| *buf = '\0'; |
| return; |
| } |
| if (d->ext[i] == FAT_DENTRY_E5_ESC) |
| *buf++ = 0xe5; |
| else |
| *buf++ = d->ext[i]; |
| } |
| } |
| |
| /* TODO move somewhere else */ |
| typedef struct { |
| void *data; |
| } block_t; |
| |
| static block_t *block_get(dev_handle_t dev_handle, off_t offset) |
| { |
| return NULL; /* TODO */ |
| } |
| |
| static void block_put(block_t *block) |
| { |
| /* TODO */ |
| } |
| |
| #define FAT_BS(b) ((fat_bs_t *)((b)->data)) |
| |
| #define FAT_CLST_RES0 0x0000 |
| #define FAT_CLST_RES1 0x0001 /* internally used to mark root directory */ |
| #define FAT_CLST_FIRST 0x0002 |
| #define FAT_CLST_BAD 0xfff7 |
| #define FAT_CLST_LAST1 0xfff8 |
| #define FAT_CLST_LAST8 0xffff |
| |
| #define fat_block_get(np, off) \ |
| _fat_block_get((np)->idx->dev_handle, (np)->firstc, (off)) |
| |
| static block_t * |
| _fat_block_get(dev_handle_t dev_handle, fat_cluster_t firstc, off_t offset) |
| { |
| block_t *bb; |
| block_t *b; |
| unsigned bps; |
| unsigned spc; |
| unsigned rscnt; /* block address of the first FAT */ |
| unsigned fatcnt; |
| unsigned rde; |
| unsigned rds; /* root directory size */ |
| unsigned sf; |
| unsigned ssa; /* size of the system area */ |
| unsigned clusters; |
| fat_cluster_t clst = firstc; |
| unsigned i; |
| |
| bb = block_get(dev_handle, BS_BLOCK); |
| bps = uint16_t_le2host(FAT_BS(bb)->bps); |
| spc = FAT_BS(bb)->spc; |
| rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt); |
| fatcnt = FAT_BS(bb)->fatcnt; |
| rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max); |
| sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat); |
| block_put(bb); |
| |
| rds = (sizeof(fat_dentry_t) * rde) / bps; |
| rds += ((sizeof(fat_dentry_t) * rde) % bps != 0); |
| ssa = rscnt + fatcnt * sf + rds; |
| |
| if (firstc == FAT_CLST_RES1) { |
| /* root directory special case */ |
| assert(offset < rds); |
| b = block_get(dev_handle, rscnt + fatcnt * sf + offset); |
| return b; |
| } |
| |
| clusters = offset / spc; |
| for (i = 0; i < clusters; i++) { |
| unsigned fsec; /* sector offset relative to FAT1 */ |
| unsigned fidx; /* FAT1 entry index */ |
| |
| assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD); |
| fsec = (clst * sizeof(fat_cluster_t)) / bps; |
| fidx = clst % (bps / sizeof(fat_cluster_t)); |
| /* read FAT1 */ |
| b = block_get(dev_handle, rscnt + fsec); |
| clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]); |
| assert(clst != FAT_CLST_BAD); |
| assert(clst < FAT_CLST_LAST1); |
| block_put(b); |
| } |
| |
| b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc + |
| offset % spc); |
| |
| return b; |
| } |
| |
| static void fat_node_initialize(fat_node_t *node) |
| { |
| node->idx = NULL; |
| node->type = 0; |
| link_initialize(&node->ffn_link); |
| node->size = 0; |
| node->lnkcnt = 0; |
| node->refcnt = 0; |
| node->dirty = false; |
| } |
| |
| static uint16_t fat_bps_get(dev_handle_t dev_handle) |
| { |
| block_t *bb; |
| uint16_t bps; |
| |
| bb = block_get(dev_handle, BS_BLOCK); |
| assert(bb != NULL); |
| bps = uint16_t_le2host(FAT_BS(bb)->bps); |
| block_put(bb); |
| |
| return bps; |
| } |
| |
| typedef enum { |
| FAT_DENTRY_SKIP, |
| FAT_DENTRY_LAST, |
| FAT_DENTRY_VALID |
| } fat_dentry_clsf_t; |
| |
| static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d) |
| { |
| if (d->attr & FAT_ATTR_VOLLABEL) { |
| /* volume label entry */ |
| return FAT_DENTRY_SKIP; |
| } |
| if (d->name[0] == FAT_DENTRY_ERASED) { |
| /* not-currently-used entry */ |
| return FAT_DENTRY_SKIP; |
| } |
| if (d->name[0] == FAT_DENTRY_UNUSED) { |
| /* never used entry */ |
| return FAT_DENTRY_LAST; |
| } |
| if (d->name[0] == FAT_DENTRY_DOT) { |
| /* |
| * Most likely '.' or '..'. |
| * It cannot occur in a regular file name. |
| */ |
| return FAT_DENTRY_SKIP; |
| } |
| return FAT_DENTRY_VALID; |
| } |
| |
| static void fat_node_sync(fat_node_t *node) |
| { |
| /* TODO */ |
| } |
| |
| /** Instantiate a FAT in-core node. */ |
| static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index) |
| { |
| fat_idx_t *idx; |
| block_t *b; |
| fat_dentry_t *d; |
| fat_node_t *nodep; |
| unsigned bps; |
| unsigned dps; |
| |
| idx = fat_idx_get_by_index(dev_handle, index); |
| if (!idx) |
| return NULL; |
| |
| if (idx->nodep) { |
| /* |
| * We are lucky. |
| * The node is already instantiated in memory. |
| */ |
| if (!idx->nodep->refcnt++) |
| list_remove(&nodep->ffn_link); |
| return idx->nodep; |
| } |
| |
| /* |
| * We must instantiate the node from the file system. |
| */ |
| |
| assert(idx->pfc); |
| |
| if (!list_empty(&ffn_head)) { |
| /* Try to use a cached unused node structure. */ |
| nodep = list_get_instance(ffn_head.next, fat_node_t, ffn_link); |
| if (nodep->dirty) |
| fat_node_sync(nodep); |
| list_remove(&nodep->ffn_link); |
| nodep->idx->nodep = NULL; |
| } else { |
| /* Try to allocate a new node structure. */ |
| nodep = (fat_node_t *)malloc(sizeof(fat_node_t)); |
| if (!nodep) |
| return NULL; |
| } |
| fat_node_initialize(nodep); |
| |
| bps = fat_bps_get(dev_handle); |
| dps = bps / sizeof(fat_dentry_t); |
| |
| /* Read the block that contains the dentry of interest. */ |
| b = _fat_block_get(dev_handle, idx->pfc, |
| (idx->pdi * sizeof(fat_dentry_t)) / bps); |
| assert(b); |
| |
| d = ((fat_dentry_t *)b->data) + (idx->pdi % dps); |
| if (d->attr & FAT_ATTR_SUBDIR) { |
| /* |
| * The only directory which does not have this bit set is the |
| * root directory itself. The root directory node is handled |
| * and initialized elsewhere. |
| */ |
| nodep->type = FAT_DIRECTORY; |
| } else { |
| nodep->type = FAT_FILE; |
| } |
| nodep->firstc = uint16_t_le2host(d->firstc); |
| nodep->size = uint32_t_le2host(d->size); |
| nodep->lnkcnt = 1; |
| nodep->refcnt = 1; |
| |
| block_put(b); |
| |
| /* Link the idx structure with the node structure. */ |
| nodep->idx = idx; |
| idx->nodep = nodep; |
| |
| return nodep; |
| } |
| |
| static void fat_node_put(void *node) |
| { |
| fat_node_t *nodep = (fat_node_t *)node; |
| |
| if (!--nodep->refcnt) { |
| list_append(&nodep->ffn_link, &ffn_head); |
| } |
| } |
| |
| static void *fat_create(int flags) |
| { |
| return NULL; /* not supported at the moment */ |
| } |
| |
| static int fat_destroy(void *node) |
| { |
| return ENOTSUP; /* not supported at the moment */ |
| } |
| |
| static bool fat_link(void *prnt, void *chld, const char *name) |
| { |
| return false; /* not supported at the moment */ |
| } |
| |
| static int fat_unlink(void *prnt, void *chld) |
| { |
| return ENOTSUP; /* not supported at the moment */ |
| } |
| |
| static void *fat_match(void *prnt, const char *component) |
| { |
| fat_node_t *parentp = (fat_node_t *)prnt; |
| char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1]; |
| unsigned i, j; |
| unsigned bps; /* bytes per sector */ |
| unsigned dps; /* dentries per sector */ |
| unsigned blocks; |
| fat_dentry_t *d; |
| block_t *b; |
| |
| bps = fat_bps_get(parentp->idx->dev_handle); |
| dps = bps / sizeof(fat_dentry_t); |
| blocks = parentp->size / bps + (parentp->size % bps != 0); |
| for (i = 0; i < blocks; i++) { |
| unsigned dentries; |
| |
| b = fat_block_get(parentp, i); |
| dentries = (i == blocks - 1) ? |
| parentp->size % sizeof(fat_dentry_t) : |
| dps; |
| for (j = 0; j < dentries; j++) { |
| d = ((fat_dentry_t *)b->data) + j; |
| switch (fat_classify_dentry(d)) { |
| case FAT_DENTRY_SKIP: |
| continue; |
| case FAT_DENTRY_LAST: |
| block_put(b); |
| return NULL; |
| default: |
| case FAT_DENTRY_VALID: |
| dentry_name_canonify(d, name); |
| break; |
| } |
| if (strcmp(name, component) == 0) { |
| /* hit */ |
| fat_idx_t *idx = fat_idx_get_by_pos( |
| parentp->idx->dev_handle, parentp->firstc, |
| i * dps + j); |
| if (!idx) { |
| /* |
| * Can happen if memory is low or if we |
| * run out of 32-bit indices. |
| */ |
| block_put(b); |
| return NULL; |
| } |
| void *node = fat_node_get(idx->dev_handle, |
| idx->index); |
| block_put(b); |
| return node; |
| } |
| } |
| block_put(b); |
| } |
| |
| return NULL; |
| } |
| |
| static fs_index_t fat_index_get(void *node) |
| { |
| fat_node_t *fnodep = (fat_node_t *)node; |
| if (!fnodep) |
| return 0; |
| return fnodep->idx->index; |
| } |
| |
| static size_t fat_size_get(void *node) |
| { |
| return ((fat_node_t *)node)->size; |
| } |
| |
| static unsigned fat_lnkcnt_get(void *node) |
| { |
| return ((fat_node_t *)node)->lnkcnt; |
| } |
| |
| static bool fat_has_children(void *node) |
| { |
| fat_node_t *nodep = (fat_node_t *)node; |
| unsigned bps; |
| unsigned dps; |
| unsigned blocks; |
| block_t *b; |
| unsigned i, j; |
| |
| if (nodep->type != FAT_DIRECTORY) |
| return false; |
| |
| bps = fat_bps_get(nodep->idx->dev_handle); |
| dps = bps / sizeof(fat_dentry_t); |
| |
| blocks = nodep->size / bps + (nodep->size % bps != 0); |
| |
| for (i = 0; i < blocks; i++) { |
| unsigned dentries; |
| fat_dentry_t *d; |
| |
| b = fat_block_get(nodep, i); |
| dentries = (i == blocks - 1) ? |
| nodep->size % sizeof(fat_dentry_t) : |
| dps; |
| for (j = 0; j < dentries; j++) { |
| d = ((fat_dentry_t *)b->data) + j; |
| switch (fat_classify_dentry(d)) { |
| case FAT_DENTRY_SKIP: |
| continue; |
| case FAT_DENTRY_LAST: |
| block_put(b); |
| return false; |
| default: |
| case FAT_DENTRY_VALID: |
| block_put(b); |
| return true; |
| } |
| block_put(b); |
| return true; |
| } |
| block_put(b); |
| } |
| |
| return false; |
| } |
| |
| static void *fat_root_get(dev_handle_t dev_handle) |
| { |
| return NULL; /* TODO */ |
| } |
| |
| static char fat_plb_get_char(unsigned pos) |
| { |
| return fat_reg.plb_ro[pos % PLB_SIZE]; |
| } |
| |
| static bool fat_is_directory(void *node) |
| { |
| return ((fat_node_t *)node)->type == FAT_DIRECTORY; |
| } |
| |
| static bool fat_is_file(void *node) |
| { |
| return ((fat_node_t *)node)->type == FAT_FILE; |
| } |
| |
| /** libfs operations */ |
| libfs_ops_t fat_libfs_ops = { |
| .match = fat_match, |
| .node_get = fat_node_get, |
| .node_put = fat_node_put, |
| .create = fat_create, |
| .destroy = fat_destroy, |
| .link = fat_link, |
| .unlink = fat_unlink, |
| .index_get = fat_index_get, |
| .size_get = fat_size_get, |
| .lnkcnt_get = fat_lnkcnt_get, |
| .has_children = fat_has_children, |
| .root_get = fat_root_get, |
| .plb_get_char = fat_plb_get_char, |
| .is_directory = fat_is_directory, |
| .is_file = fat_is_file |
| }; |
| |
| void fat_lookup(ipc_callid_t rid, ipc_call_t *request) |
| { |
| libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request); |
| } |
| |
| /** |
| * @} |
| */ |