| 0,0 → 1,1130 |
|---|
| /* |
| * 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 "fat_dentry.h" |
| #include "fat_fat.h" |
| #include "../../vfs/vfs.h" |
| #include <libfs.h> |
| #include <libblock.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> |
| #include <align.h> |
| |
| /** 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); |
| |
| 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 void fat_node_sync(fat_node_t *node) |
| { |
| block_t *b; |
| fat_bs_t *bs; |
| fat_dentry_t *d; |
| uint16_t bps; |
| unsigned dps; |
| |
| assert(node->dirty); |
| |
| bs = block_bb_get(node->idx->dev_handle); |
| bps = uint16_t_le2host(bs->bps); |
| dps = bps / sizeof(fat_dentry_t); |
| |
| /* Read the block that contains the dentry of interest. */ |
| b = _fat_block_get(bs, node->idx->dev_handle, node->idx->pfc, |
| (node->idx->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE); |
| |
| d = ((fat_dentry_t *)b->data) + (node->idx->pdi % dps); |
| |
| d->firstc = host2uint16_t_le(node->firstc); |
| if (node->type == FAT_FILE) { |
| d->size = host2uint32_t_le(node->size); |
| } else if (node->type == FAT_DIRECTORY) { |
| d->attr = FAT_ATTR_SUBDIR; |
| } |
| |
| /* TODO: update other fields? (e.g time fields) */ |
| |
| b->dirty = true; /* need to sync block */ |
| block_put(b); |
| } |
| |
| static fat_node_t *fat_node_get_new(void) |
| { |
| fat_node_t *nodep; |
| |
| 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); |
| |
| return nodep; |
| } |
| |
| /** 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_bs_t *bs; |
| fat_dentry_t *d; |
| fat_node_t *nodep = NULL; |
| unsigned bps; |
| unsigned spc; |
| 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); |
| |
| nodep = fat_node_get_new(); |
| if (!nodep) |
| return NULL; |
| |
| bs = block_bb_get(idxp->dev_handle); |
| bps = uint16_t_le2host(bs->bps); |
| spc = bs->spc; |
| dps = bps / sizeof(fat_dentry_t); |
| |
| /* Read the block that contains the dentry of interest. */ |
| b = _fat_block_get(bs, idxp->dev_handle, idxp->pfc, |
| (idxp->pdi * sizeof(fat_dentry_t)) / bps, BLOCK_FLAGS_NONE); |
| 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; |
| /* |
| * Unfortunately, the 'size' field of the FAT dentry is not |
| * defined for the directory entry type. We must determine the |
| * size of the directory by walking the FAT. |
| */ |
| nodep->size = bps * spc * fat_clusters_get(bs, idxp->dev_handle, |
| uint16_t_le2host(d->firstc)); |
| } 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; |
| } |
| |
| /* |
| * Forward declarations of FAT libfs operations. |
| */ |
| static void *fat_node_get(dev_handle_t, fs_index_t); |
| static void fat_node_put(void *); |
| static void *fat_create_node(dev_handle_t, int); |
| static int fat_destroy_node(void *); |
| static int fat_link(void *, void *, const char *); |
| static int fat_unlink(void *, void *); |
| static void *fat_match(void *, const char *); |
| static fs_index_t fat_index_get(void *); |
| static size_t fat_size_get(void *); |
| static unsigned fat_lnkcnt_get(void *); |
| static bool fat_has_children(void *); |
| static void *fat_root_get(dev_handle_t); |
| static char fat_plb_get_char(unsigned); |
| static bool fat_is_directory(void *); |
| static bool fat_is_file(void *node); |
| |
| /* |
| * FAT libfs operations. |
| */ |
| |
| /** Instantiate a FAT in-core node. */ |
| 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; |
| } |
| |
| void fat_node_put(void *node) |
| { |
| fat_node_t *nodep = (fat_node_t *)node; |
| bool destroy = false; |
| |
| futex_down(&nodep->lock); |
| if (!--nodep->refcnt) { |
| if (nodep->idx) { |
| futex_down(&ffn_futex); |
| list_append(&nodep->ffn_link, &ffn_head); |
| futex_up(&ffn_futex); |
| } else { |
| /* |
| * The node does not have any index structure associated |
| * with itself. This can only mean that we are releasing |
| * the node after a failed attempt to allocate the index |
| * structure for it. |
| */ |
| destroy = true; |
| } |
| } |
| futex_up(&nodep->lock); |
| if (destroy) |
| free(node); |
| } |
| |
| void *fat_create_node(dev_handle_t dev_handle, int flags) |
| { |
| fat_idx_t *idxp; |
| fat_node_t *nodep; |
| fat_bs_t *bs; |
| fat_cluster_t mcl, lcl; |
| uint16_t bps; |
| int rc; |
| |
| bs = block_bb_get(dev_handle); |
| bps = uint16_t_le2host(bs->bps); |
| if (flags & L_DIRECTORY) { |
| /* allocate a cluster */ |
| rc = fat_alloc_clusters(bs, dev_handle, 1, &mcl, &lcl); |
| if (rc != EOK) |
| return NULL; |
| } |
| |
| nodep = fat_node_get_new(); |
| if (!nodep) { |
| fat_free_clusters(bs, dev_handle, mcl); |
| return NULL; |
| } |
| idxp = fat_idx_get_new(dev_handle); |
| if (!idxp) { |
| fat_free_clusters(bs, dev_handle, mcl); |
| fat_node_put(nodep); |
| return NULL; |
| } |
| /* idxp->lock held */ |
| if (flags & L_DIRECTORY) { |
| int i; |
| block_t *b; |
| |
| /* |
| * Populate the new cluster with unused dentries. |
| */ |
| for (i = 0; i < bs->spc; i++) { |
| b = _fat_block_get(bs, dev_handle, mcl, i, |
| BLOCK_FLAGS_NOREAD); |
| /* mark all dentries as never-used */ |
| memset(b->data, 0, bps); |
| b->dirty = false; |
| block_put(b); |
| } |
| nodep->type = FAT_DIRECTORY; |
| nodep->firstc = mcl; |
| nodep->size = bps * bs->spc; |
| } else { |
| nodep->type = FAT_FILE; |
| nodep->firstc = FAT_CLST_RES0; |
| nodep->size = 0; |
| } |
| nodep->lnkcnt = 0; /* not linked anywhere */ |
| nodep->refcnt = 1; |
| nodep->dirty = true; |
| |
| nodep->idx = idxp; |
| idxp->nodep = nodep; |
| |
| futex_up(&idxp->lock); |
| return nodep; |
| } |
| |
| int fat_destroy_node(void *node) |
| { |
| fat_node_t *nodep = (fat_node_t *)node; |
| fat_bs_t *bs; |
| |
| /* |
| * The node is not reachable from the file system. This means that the |
| * link count should be zero and that the index structure cannot be |
| * found in the position hash. Obviously, we don't need to lock the node |
| * nor its index structure. |
| */ |
| assert(nodep->lnkcnt == 0); |
| |
| /* |
| * The node may not have any children. |
| */ |
| assert(fat_has_children(node) == false); |
| |
| bs = block_bb_get(nodep->idx->dev_handle); |
| if (nodep->firstc != FAT_CLST_RES0) { |
| assert(nodep->size); |
| /* Free all clusters allocated to the node. */ |
| fat_free_clusters(bs, nodep->idx->dev_handle, nodep->firstc); |
| } |
| |
| fat_idx_destroy(nodep->idx); |
| free(nodep); |
| return EOK; |
| } |
| |
| int fat_link(void *prnt, void *chld, const char *name) |
| { |
| fat_node_t *parentp = (fat_node_t *)prnt; |
| fat_node_t *childp = (fat_node_t *)chld; |
| fat_dentry_t *d; |
| fat_bs_t *bs; |
| block_t *b; |
| int i, j; |
| uint16_t bps; |
| unsigned dps; |
| unsigned blocks; |
| fat_cluster_t mcl, lcl; |
| int rc; |
| |
| futex_down(&childp->lock); |
| if (childp->lnkcnt == 1) { |
| /* |
| * On FAT, we don't support multiple hard links. |
| */ |
| futex_up(&childp->lock); |
| return EMLINK; |
| } |
| assert(childp->lnkcnt == 0); |
| futex_up(&childp->lock); |
| |
| if (!fat_dentry_name_verify(name)) { |
| /* |
| * Attempt to create unsupported name. |
| */ |
| return ENOTSUP; |
| } |
| |
| /* |
| * Get us an unused parent node's dentry or grow the parent and allocate |
| * a new one. |
| */ |
| |
| futex_down(&parentp->idx->lock); |
| bs = block_bb_get(parentp->idx->dev_handle); |
| bps = uint16_t_le2host(bs->bps); |
| dps = bps / sizeof(fat_dentry_t); |
| |
| blocks = parentp->size / bps; |
| |
| for (i = 0; i < blocks; i++) { |
| b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE); |
| for (j = 0; j < dps; j++) { |
| d = ((fat_dentry_t *)b->data) + j; |
| switch (fat_classify_dentry(d)) { |
| case FAT_DENTRY_SKIP: |
| case FAT_DENTRY_VALID: |
| /* skipping used and meta entries */ |
| continue; |
| case FAT_DENTRY_FREE: |
| case FAT_DENTRY_LAST: |
| /* found an empty slot */ |
| goto hit; |
| } |
| } |
| block_put(b); |
| } |
| j = 0; |
| |
| /* |
| * We need to grow the parent in order to create a new unused dentry. |
| */ |
| if (parentp->idx->pfc == FAT_CLST_ROOT) { |
| /* Can't grow the root directory. */ |
| futex_up(&parentp->idx->lock); |
| return ENOSPC; |
| } |
| rc = fat_alloc_clusters(bs, parentp->idx->dev_handle, 1, &mcl, &lcl); |
| if (rc != EOK) { |
| futex_up(&parentp->idx->lock); |
| return rc; |
| } |
| fat_append_clusters(bs, parentp, mcl); |
| b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NOREAD); |
| d = (fat_dentry_t *)b->data; |
| /* |
| * Clear all dentries in the block except for the first one (the first |
| * dentry will be cleared in the next step). |
| */ |
| memset(d + 1, 0, bps - sizeof(fat_dentry_t)); |
| |
| hit: |
| /* |
| * At this point we only establish the link between the parent and the |
| * child. The dentry, except of the name and the extension, will remain |
| * uninitialized until the corresponding node is synced. Thus the valid |
| * dentry data is kept in the child node structure. |
| */ |
| memset(d, 0, sizeof(fat_dentry_t)); |
| fat_dentry_name_set(d, name); |
| b->dirty = true; /* need to sync block */ |
| block_put(b); |
| futex_up(&parentp->idx->lock); |
| |
| futex_down(&childp->idx->lock); |
| |
| /* |
| * If possible, create the Sub-directory Identifier Entry and the |
| * Sub-directory Parent Pointer Entry (i.e. "." and ".."). These entries |
| * are not mandatory according to Standard ECMA-107 and HelenOS VFS does |
| * not use them anyway, so this is rather a sign of our good will. |
| */ |
| b = fat_block_get(bs, childp, 0, BLOCK_FLAGS_NONE); |
| d = (fat_dentry_t *)b->data; |
| if (fat_classify_dentry(d) == FAT_DENTRY_LAST || |
| str_cmp(d->name, FAT_NAME_DOT) == 0) { |
| memset(d, 0, sizeof(fat_dentry_t)); |
| str_cpy(d->name, 8, FAT_NAME_DOT); |
| str_cpy(d->ext, 3, FAT_EXT_PAD); |
| d->attr = FAT_ATTR_SUBDIR; |
| d->firstc = host2uint16_t_le(childp->firstc); |
| /* TODO: initialize also the date/time members. */ |
| } |
| d++; |
| if (fat_classify_dentry(d) == FAT_DENTRY_LAST || |
| str_cmp(d->name, FAT_NAME_DOT_DOT) == 0) { |
| memset(d, 0, sizeof(fat_dentry_t)); |
| str_cpy(d->name, 8, FAT_NAME_DOT_DOT); |
| str_cpy(d->ext, 3, FAT_EXT_PAD); |
| d->attr = FAT_ATTR_SUBDIR; |
| d->firstc = (parentp->firstc == FAT_CLST_ROOT) ? |
| host2uint16_t_le(FAT_CLST_RES0) : |
| host2uint16_t_le(parentp->firstc); |
| /* TODO: initialize also the date/time members. */ |
| } |
| b->dirty = true; /* need to sync block */ |
| block_put(b); |
| |
| childp->idx->pfc = parentp->firstc; |
| childp->idx->pdi = i * dps + j; |
| futex_up(&childp->idx->lock); |
| |
| futex_down(&childp->lock); |
| childp->lnkcnt = 1; |
| childp->dirty = true; /* need to sync node */ |
| futex_up(&childp->lock); |
| |
| /* |
| * Hash in the index structure into the position hash. |
| */ |
| fat_idx_hashin(childp->idx); |
| |
| return EOK; |
| } |
| |
| int fat_unlink(void *prnt, void *chld) |
| { |
| fat_node_t *parentp = (fat_node_t *)prnt; |
| fat_node_t *childp = (fat_node_t *)chld; |
| fat_bs_t *bs; |
| fat_dentry_t *d; |
| uint16_t bps; |
| block_t *b; |
| |
| futex_down(&parentp->lock); |
| futex_down(&childp->lock); |
| assert(childp->lnkcnt == 1); |
| futex_down(&childp->idx->lock); |
| bs = block_bb_get(childp->idx->dev_handle); |
| bps = uint16_t_le2host(bs->bps); |
| |
| b = _fat_block_get(bs, childp->idx->dev_handle, childp->idx->pfc, |
| (childp->idx->pdi * sizeof(fat_dentry_t)) / bps, |
| BLOCK_FLAGS_NONE); |
| d = (fat_dentry_t *)b->data + |
| (childp->idx->pdi % (bps / sizeof(fat_dentry_t))); |
| /* mark the dentry as not-currently-used */ |
| d->name[0] = FAT_DENTRY_ERASED; |
| b->dirty = true; /* need to sync block */ |
| block_put(b); |
| |
| /* remove the index structure from the position hash */ |
| fat_idx_hashout(childp->idx); |
| /* clear position information */ |
| childp->idx->pfc = FAT_CLST_RES0; |
| childp->idx->pdi = 0; |
| futex_up(&childp->idx->lock); |
| childp->lnkcnt = 0; |
| childp->dirty = true; |
| futex_up(&childp->lock); |
| futex_up(&parentp->lock); |
| |
| return EOK; |
| } |
| |
| void *fat_match(void *prnt, const char *component) |
| { |
| fat_bs_t *bs; |
| 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); |
| bs = block_bb_get(parentp->idx->dev_handle); |
| bps = uint16_t_le2host(bs->bps); |
| dps = bps / sizeof(fat_dentry_t); |
| blocks = parentp->size / bps; |
| for (i = 0; i < blocks; i++) { |
| b = fat_block_get(bs, parentp, i, BLOCK_FLAGS_NONE); |
| for (j = 0; j < dps; j++) { |
| d = ((fat_dentry_t *)b->data) + j; |
| switch (fat_classify_dentry(d)) { |
| case FAT_DENTRY_SKIP: |
| case FAT_DENTRY_FREE: |
| continue; |
| case FAT_DENTRY_LAST: |
| block_put(b); |
| futex_up(&parentp->idx->lock); |
| return NULL; |
| default: |
| case FAT_DENTRY_VALID: |
| fat_dentry_name_get(d, name); |
| break; |
| } |
| if (fat_dentry_namecmp(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; |
| } |
| |
| fs_index_t fat_index_get(void *node) |
| { |
| fat_node_t *fnodep = (fat_node_t *)node; |
| if (!fnodep) |
| return 0; |
| return fnodep->idx->index; |
| } |
| |
| size_t fat_size_get(void *node) |
| { |
| return ((fat_node_t *)node)->size; |
| } |
| |
| unsigned fat_lnkcnt_get(void *node) |
| { |
| return ((fat_node_t *)node)->lnkcnt; |
| } |
| |
| bool fat_has_children(void *node) |
| { |
| fat_bs_t *bs; |
| 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); |
| bs = block_bb_get(nodep->idx->dev_handle); |
| bps = uint16_t_le2host(bs->bps); |
| dps = bps / sizeof(fat_dentry_t); |
| |
| blocks = nodep->size / bps; |
| |
| for (i = 0; i < blocks; i++) { |
| fat_dentry_t *d; |
| |
| b = fat_block_get(bs, nodep, i, BLOCK_FLAGS_NONE); |
| for (j = 0; j < dps; j++) { |
| d = ((fat_dentry_t *)b->data) + j; |
| switch (fat_classify_dentry(d)) { |
| case FAT_DENTRY_SKIP: |
| case FAT_DENTRY_FREE: |
| 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; |
| } |
| |
| void *fat_root_get(dev_handle_t dev_handle) |
| { |
| return fat_node_get(dev_handle, 0); |
| } |
| |
| char fat_plb_get_char(unsigned pos) |
| { |
| return fat_reg.plb_ro[pos % PLB_SIZE]; |
| } |
| |
| bool fat_is_directory(void *node) |
| { |
| return ((fat_node_t *)node)->type == FAT_DIRECTORY; |
| } |
| |
| 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_node, |
| .destroy = fat_destroy_node, |
| .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 |
| }; |
| |
| /* |
| * VFS operations. |
| */ |
| |
| void fat_mounted(ipc_callid_t rid, ipc_call_t *request) |
| { |
| dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request); |
| fat_bs_t *bs; |
| uint16_t bps; |
| uint16_t rde; |
| int rc; |
| |
| /* initialize libblock */ |
| rc = block_init(dev_handle, BS_SIZE); |
| if (rc != EOK) { |
| ipc_answer_0(rid, rc); |
| return; |
| } |
| |
| /* prepare the boot block */ |
| rc = block_bb_read(dev_handle, BS_BLOCK * BS_SIZE, BS_SIZE); |
| if (rc != EOK) { |
| block_fini(dev_handle); |
| ipc_answer_0(rid, rc); |
| return; |
| } |
| |
| /* get the buffer with the boot sector */ |
| bs = block_bb_get(dev_handle); |
| |
| /* Read the number of root directory entries. */ |
| bps = uint16_t_le2host(bs->bps); |
| rde = uint16_t_le2host(bs->root_ent_max); |
| |
| if (bps != BS_SIZE) { |
| block_fini(dev_handle); |
| ipc_answer_0(rid, ENOTSUP); |
| return; |
| } |
| |
| /* Initialize the block cache */ |
| rc = block_cache_init(dev_handle, bps, 0 /* XXX */); |
| if (rc != EOK) { |
| block_fini(dev_handle); |
| ipc_answer_0(rid, rc); |
| return; |
| } |
| |
| rc = fat_idx_init_by_dev_handle(dev_handle); |
| if (rc != EOK) { |
| block_fini(dev_handle); |
| ipc_answer_0(rid, rc); |
| return; |
| } |
| |
| /* Initialize the root node. */ |
| fat_node_t *rootp = (fat_node_t *)malloc(sizeof(fat_node_t)); |
| if (!rootp) { |
| block_fini(dev_handle); |
| 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) { |
| block_fini(dev_handle); |
| 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->lnkcnt = 0; /* FS root is not linked */ |
| rootp->size = rde * sizeof(fat_dentry_t); |
| rootp->idx = ridxp; |
| ridxp->nodep = rootp; |
| |
| futex_up(&ridxp->lock); |
| |
| ipc_answer_3(rid, EOK, ridxp->index, rootp->size, rootp->lnkcnt); |
| } |
| |
| 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); |
| fat_bs_t *bs; |
| uint16_t bps; |
| size_t bytes; |
| block_t *b; |
| |
| if (!nodep) { |
| ipc_answer_0(rid, ENOENT); |
| return; |
| } |
| |
| ipc_callid_t callid; |
| size_t len; |
| if (!ipc_data_read_receive(&callid, &len)) { |
| fat_node_put(nodep); |
| ipc_answer_0(callid, EINVAL); |
| ipc_answer_0(rid, EINVAL); |
| return; |
| } |
| |
| bs = block_bb_get(dev_handle); |
| bps = uint16_t_le2host(bs->bps); |
| |
| if (nodep->type == FAT_FILE) { |
| /* |
| * Our strategy for regular file reads is to read one block at |
| * most and make use of the possibility to return less data than |
| * requested. This keeps the code very simple. |
| */ |
| if (pos >= nodep->size) { |
| /* reading beyond the EOF */ |
| bytes = 0; |
| (void) ipc_data_read_finalize(callid, NULL, 0); |
| } else { |
| bytes = min(len, bps - pos % bps); |
| bytes = min(bytes, nodep->size - pos); |
| b = fat_block_get(bs, nodep, pos / bps, |
| BLOCK_FLAGS_NONE); |
| (void) ipc_data_read_finalize(callid, b->data + pos % bps, |
| bytes); |
| block_put(b); |
| } |
| } else { |
| unsigned bnum; |
| off_t spos = pos; |
| char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1]; |
| fat_dentry_t *d; |
| |
| assert(nodep->type == FAT_DIRECTORY); |
| assert(nodep->size % bps == 0); |
| assert(bps % sizeof(fat_dentry_t) == 0); |
| |
| /* |
| * Our strategy for readdir() is to use the position pointer as |
| * an index into the array of all dentries. On entry, it points |
| * to the first unread dentry. If we skip any dentries, we bump |
| * the position pointer accordingly. |
| */ |
| bnum = (pos * sizeof(fat_dentry_t)) / bps; |
| while (bnum < nodep->size / bps) { |
| off_t o; |
| |
| b = fat_block_get(bs, nodep, bnum, BLOCK_FLAGS_NONE); |
| for (o = pos % (bps / sizeof(fat_dentry_t)); |
| o < bps / sizeof(fat_dentry_t); |
| o++, pos++) { |
| d = ((fat_dentry_t *)b->data) + o; |
| switch (fat_classify_dentry(d)) { |
| case FAT_DENTRY_SKIP: |
| case FAT_DENTRY_FREE: |
| continue; |
| case FAT_DENTRY_LAST: |
| block_put(b); |
| goto miss; |
| default: |
| case FAT_DENTRY_VALID: |
| fat_dentry_name_get(d, name); |
| block_put(b); |
| goto hit; |
| } |
| } |
| block_put(b); |
| bnum++; |
| } |
| miss: |
| fat_node_put(nodep); |
| ipc_answer_0(callid, ENOENT); |
| ipc_answer_1(rid, ENOENT, 0); |
| return; |
| hit: |
| (void) ipc_data_read_finalize(callid, name, str_size(name) + 1); |
| bytes = (pos - spos) + 1; |
| } |
| |
| fat_node_put(nodep); |
| ipc_answer_1(rid, EOK, (ipcarg_t)bytes); |
| } |
| |
| void fat_write(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); |
| fat_bs_t *bs; |
| size_t bytes; |
| block_t *b; |
| uint16_t bps; |
| unsigned spc; |
| unsigned bpc; /* bytes per cluster */ |
| off_t boundary; |
| int flags = BLOCK_FLAGS_NONE; |
| |
| 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; |
| } |
| |
| bs = block_bb_get(dev_handle); |
| bps = uint16_t_le2host(bs->bps); |
| spc = bs->spc; |
| bpc = bps * spc; |
| |
| /* |
| * In all scenarios, we will attempt to write out only one block worth |
| * of data at maximum. There might be some more efficient approaches, |
| * but this one greatly simplifies fat_write(). Note that we can afford |
| * to do this because the client must be ready to handle the return |
| * value signalizing a smaller number of bytes written. |
| */ |
| bytes = min(len, bps - pos % bps); |
| if (bytes == bps) |
| flags |= BLOCK_FLAGS_NOREAD; |
| |
| boundary = ROUND_UP(nodep->size, bpc); |
| if (pos < boundary) { |
| /* |
| * This is the easier case - we are either overwriting already |
| * existing contents or writing behind the EOF, but still within |
| * the limits of the last cluster. The node size may grow to the |
| * next block size boundary. |
| */ |
| fat_fill_gap(bs, nodep, FAT_CLST_RES0, pos); |
| b = fat_block_get(bs, nodep, pos / bps, flags); |
| (void) ipc_data_write_finalize(callid, b->data + pos % bps, |
| bytes); |
| b->dirty = true; /* need to sync block */ |
| block_put(b); |
| if (pos + bytes > nodep->size) { |
| nodep->size = pos + bytes; |
| nodep->dirty = true; /* need to sync node */ |
| } |
| ipc_answer_2(rid, EOK, bytes, nodep->size); |
| fat_node_put(nodep); |
| return; |
| } else { |
| /* |
| * This is the more difficult case. We must allocate new |
| * clusters for the node and zero them out. |
| */ |
| int status; |
| unsigned nclsts; |
| fat_cluster_t mcl, lcl; |
| |
| nclsts = (ROUND_UP(pos + bytes, bpc) - boundary) / bpc; |
| /* create an independent chain of nclsts clusters in all FATs */ |
| status = fat_alloc_clusters(bs, dev_handle, nclsts, &mcl, &lcl); |
| if (status != EOK) { |
| /* could not allocate a chain of nclsts clusters */ |
| fat_node_put(nodep); |
| ipc_answer_0(callid, status); |
| ipc_answer_0(rid, status); |
| return; |
| } |
| /* zero fill any gaps */ |
| fat_fill_gap(bs, nodep, mcl, pos); |
| b = _fat_block_get(bs, dev_handle, lcl, (pos / bps) % spc, |
| flags); |
| (void) ipc_data_write_finalize(callid, b->data + pos % bps, |
| bytes); |
| b->dirty = true; /* need to sync block */ |
| block_put(b); |
| /* |
| * Append the cluster chain starting in mcl to the end of the |
| * node's cluster chain. |
| */ |
| fat_append_clusters(bs, nodep, mcl); |
| nodep->size = pos + bytes; |
| nodep->dirty = true; /* need to sync node */ |
| ipc_answer_2(rid, EOK, bytes, nodep->size); |
| fat_node_put(nodep); |
| return; |
| } |
| } |
| |
| void fat_truncate(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); |
| size_t size = (off_t)IPC_GET_ARG3(*request); |
| fat_node_t *nodep = (fat_node_t *)fat_node_get(dev_handle, index); |
| fat_bs_t *bs; |
| uint16_t bps; |
| uint8_t spc; |
| unsigned bpc; /* bytes per cluster */ |
| int rc; |
| |
| if (!nodep) { |
| ipc_answer_0(rid, ENOENT); |
| return; |
| } |
| |
| bs = block_bb_get(dev_handle); |
| bps = uint16_t_le2host(bs->bps); |
| spc = bs->spc; |
| bpc = bps * spc; |
| |
| if (nodep->size == size) { |
| rc = EOK; |
| } else if (nodep->size < size) { |
| /* |
| * The standard says we have the freedom to grow the node. |
| * For now, we simply return an error. |
| */ |
| rc = EINVAL; |
| } else if (ROUND_UP(nodep->size, bpc) == ROUND_UP(size, bpc)) { |
| /* |
| * The node will be shrunk, but no clusters will be deallocated. |
| */ |
| nodep->size = size; |
| nodep->dirty = true; /* need to sync node */ |
| rc = EOK; |
| } else { |
| /* |
| * The node will be shrunk, clusters will be deallocated. |
| */ |
| if (size == 0) { |
| fat_chop_clusters(bs, nodep, FAT_CLST_RES0); |
| } else { |
| fat_cluster_t lastc; |
| (void) fat_cluster_walk(bs, dev_handle, nodep->firstc, |
| &lastc, (size - 1) / bpc); |
| fat_chop_clusters(bs, nodep, lastc); |
| } |
| nodep->size = size; |
| nodep->dirty = true; /* need to sync node */ |
| rc = EOK; |
| } |
| fat_node_put(nodep); |
| ipc_answer_0(rid, rc); |
| return; |
| } |
| |
| void fat_destroy(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); |
| int rc; |
| |
| fat_node_t *nodep = fat_node_get(dev_handle, index); |
| if (!nodep) { |
| ipc_answer_0(rid, ENOENT); |
| return; |
| } |
| |
| rc = fat_destroy_node(nodep); |
| ipc_answer_0(rid, rc); |
| } |
| |
| /** |
| * @} |
| */ |