| 0,0 → 1,625 |
|---|
| /* |
| * 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 tmpfs_ops.c |
| * @brief Implementation of VFS operations for the TMPFS file system |
| * server. |
| */ |
| |
| #include "tmpfs.h" |
| #include "../../vfs/vfs.h" |
| #include <ipc/ipc.h> |
| #include <async.h> |
| #include <errno.h> |
| #include <atomic.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <stdio.h> |
| #include <assert.h> |
| #include <sys/types.h> |
| #include <libadt/hash_table.h> |
| #include <as.h> |
| #include <libfs.h> |
| |
| #define min(a, b) ((a) < (b) ? (a) : (b)) |
| #define max(a, b) ((a) > (b) ? (a) : (b)) |
| |
| #define DENTRIES_BUCKETS 256 |
| |
| #define NAMES_BUCKETS 4 |
| |
| /* |
| * For now, we don't distinguish between different dev_handles/instances. All |
| * requests resolve to the only instance, rooted in the following variable. |
| */ |
| static tmpfs_dentry_t *root; |
| |
| /* |
| * Implementation of the libfs interface. |
| */ |
| |
| /* Forward declarations of static functions. */ |
| static void *tmpfs_match(void *, const char *); |
| static void *tmpfs_node_get(dev_handle_t, fs_index_t); |
| static void tmpfs_node_put(void *); |
| static void *tmpfs_create_node(int); |
| static bool tmpfs_link_node(void *, void *, const char *); |
| static int tmpfs_unlink_node(void *, void *); |
| static int tmpfs_destroy_node(void *); |
| |
| /* Implementation of helper functions. */ |
| static fs_index_t tmpfs_index_get(void *nodep) |
| { |
| return ((tmpfs_dentry_t *) nodep)->index; |
| } |
| |
| static size_t tmpfs_size_get(void *nodep) |
| { |
| return ((tmpfs_dentry_t *) nodep)->size; |
| } |
| |
| static unsigned tmpfs_lnkcnt_get(void *nodep) |
| { |
| return ((tmpfs_dentry_t *) nodep)->lnkcnt; |
| } |
| |
| static bool tmpfs_has_children(void *nodep) |
| { |
| return ((tmpfs_dentry_t *) nodep)->child != NULL; |
| } |
| |
| static void *tmpfs_root_get(dev_handle_t dev_handle) |
| { |
| return root; |
| } |
| |
| static char tmpfs_plb_get_char(unsigned pos) |
| { |
| return tmpfs_reg.plb_ro[pos % PLB_SIZE]; |
| } |
| |
| static bool tmpfs_is_directory(void *nodep) |
| { |
| return ((tmpfs_dentry_t *) nodep)->type == TMPFS_DIRECTORY; |
| } |
| |
| static bool tmpfs_is_file(void *nodep) |
| { |
| return ((tmpfs_dentry_t *) nodep)->type == TMPFS_FILE; |
| } |
| |
| /** libfs operations */ |
| libfs_ops_t tmpfs_libfs_ops = { |
| .match = tmpfs_match, |
| .node_get = tmpfs_node_get, |
| .node_put = tmpfs_node_put, |
| .create = tmpfs_create_node, |
| .destroy = tmpfs_destroy_node, |
| .link = tmpfs_link_node, |
| .unlink = tmpfs_unlink_node, |
| .index_get = tmpfs_index_get, |
| .size_get = tmpfs_size_get, |
| .lnkcnt_get = tmpfs_lnkcnt_get, |
| .has_children = tmpfs_has_children, |
| .root_get = tmpfs_root_get, |
| .plb_get_char = tmpfs_plb_get_char, |
| .is_directory = tmpfs_is_directory, |
| .is_file = tmpfs_is_file |
| }; |
| |
| /** Hash table of all directory entries. */ |
| hash_table_t dentries; |
| |
| /* Implementation of hash table interface for the dentries hash table. */ |
| static hash_index_t dentries_hash(unsigned long *key) |
| { |
| return *key % DENTRIES_BUCKETS; |
| } |
| |
| static int dentries_compare(unsigned long *key, hash_count_t keys, |
| link_t *item) |
| { |
| tmpfs_dentry_t *dentry = hash_table_get_instance(item, tmpfs_dentry_t, |
| dh_link); |
| return dentry->index == *key; |
| } |
| |
| static void dentries_remove_callback(link_t *item) |
| { |
| } |
| |
| /** TMPFS dentries hash table operations. */ |
| hash_table_operations_t dentries_ops = { |
| .hash = dentries_hash, |
| .compare = dentries_compare, |
| .remove_callback = dentries_remove_callback |
| }; |
| |
| fs_index_t tmpfs_next_index = 1; |
| |
| typedef struct { |
| char *name; |
| tmpfs_dentry_t *parent; |
| link_t link; |
| } tmpfs_name_t; |
| |
| /* Implementation of hash table interface for the names hash table. */ |
| static hash_index_t names_hash(unsigned long *key) |
| { |
| tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) *key; |
| return dentry->index % NAMES_BUCKETS; |
| } |
| |
| static int names_compare(unsigned long *key, hash_count_t keys, link_t *item) |
| { |
| tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) *key; |
| tmpfs_name_t *namep = hash_table_get_instance(item, tmpfs_name_t, |
| link); |
| return dentry == namep->parent; |
| } |
| |
| static void names_remove_callback(link_t *item) |
| { |
| tmpfs_name_t *namep = hash_table_get_instance(item, tmpfs_name_t, |
| link); |
| free(namep->name); |
| free(namep); |
| } |
| |
| /** TMPFS node names hash table operations. */ |
| static hash_table_operations_t names_ops = { |
| .hash = names_hash, |
| .compare = names_compare, |
| .remove_callback = names_remove_callback |
| }; |
| |
| static void tmpfs_name_initialize(tmpfs_name_t *namep) |
| { |
| namep->name = NULL; |
| namep->parent = NULL; |
| link_initialize(&namep->link); |
| } |
| |
| static bool tmpfs_dentry_initialize(tmpfs_dentry_t *dentry) |
| { |
| dentry->index = 0; |
| dentry->sibling = NULL; |
| dentry->child = NULL; |
| dentry->type = TMPFS_NONE; |
| dentry->lnkcnt = 0; |
| dentry->size = 0; |
| dentry->data = NULL; |
| link_initialize(&dentry->dh_link); |
| return (bool)hash_table_create(&dentry->names, NAMES_BUCKETS, 1, |
| &names_ops); |
| } |
| |
| static bool tmpfs_init(void) |
| { |
| if (!hash_table_create(&dentries, DENTRIES_BUCKETS, 1, &dentries_ops)) |
| return false; |
| root = (tmpfs_dentry_t *) tmpfs_create_node(L_DIRECTORY); |
| if (!root) { |
| hash_table_destroy(&dentries); |
| return false; |
| } |
| root->lnkcnt = 0; /* FS root is not linked */ |
| return true; |
| } |
| |
| /** Compare one component of path to a directory entry. |
| * |
| * @param parentp Pointer to node from which we descended. |
| * @param childp Pointer to node to compare the path component with. |
| * @param component Array of characters holding component name. |
| * |
| * @return True on match, false otherwise. |
| */ |
| static bool |
| tmpfs_match_one(tmpfs_dentry_t *parentp, tmpfs_dentry_t *childp, |
| const char *component) |
| { |
| unsigned long key = (unsigned long) parentp; |
| link_t *hlp = hash_table_find(&childp->names, &key); |
| assert(hlp); |
| tmpfs_name_t *namep = hash_table_get_instance(hlp, tmpfs_name_t, link); |
| return !strcmp(namep->name, component); |
| } |
| |
| void *tmpfs_match(void *prnt, const char *component) |
| { |
| tmpfs_dentry_t *parentp = (tmpfs_dentry_t *) prnt; |
| tmpfs_dentry_t *childp = parentp->child; |
| |
| while (childp && !tmpfs_match_one(parentp, childp, component)) |
| childp = childp->sibling; |
| |
| return (void *) childp; |
| } |
| |
| void * |
| tmpfs_node_get(dev_handle_t dev_handle, fs_index_t index) |
| { |
| unsigned long key = index; |
| link_t *lnk = hash_table_find(&dentries, &key); |
| if (!lnk) |
| return NULL; |
| return hash_table_get_instance(lnk, tmpfs_dentry_t, dh_link); |
| } |
| |
| void tmpfs_node_put(void *node) |
| { |
| /* nothing to do */ |
| } |
| |
| void *tmpfs_create_node(int lflag) |
| { |
| assert((lflag & L_FILE) ^ (lflag & L_DIRECTORY)); |
| |
| tmpfs_dentry_t *node = malloc(sizeof(tmpfs_dentry_t)); |
| if (!node) |
| return NULL; |
| |
| if (!tmpfs_dentry_initialize(node)) { |
| free(node); |
| return NULL; |
| } |
| node->index = tmpfs_next_index++; |
| if (lflag & L_DIRECTORY) |
| node->type = TMPFS_DIRECTORY; |
| else |
| node->type = TMPFS_FILE; |
| |
| /* Insert the new node into the dentry hash table. */ |
| unsigned long key = node->index; |
| hash_table_insert(&dentries, &key, &node->dh_link); |
| return (void *) node; |
| } |
| |
| bool tmpfs_link_node(void *prnt, void *chld, const char *nm) |
| { |
| tmpfs_dentry_t *parentp = (tmpfs_dentry_t *) prnt; |
| tmpfs_dentry_t *childp = (tmpfs_dentry_t *) chld; |
| |
| assert(parentp->type == TMPFS_DIRECTORY); |
| |
| tmpfs_name_t *namep = malloc(sizeof(tmpfs_name_t)); |
| if (!namep) |
| return false; |
| tmpfs_name_initialize(namep); |
| size_t len = strlen(nm); |
| namep->name = malloc(len + 1); |
| if (!namep->name) { |
| free(namep); |
| return false; |
| } |
| strcpy(namep->name, nm); |
| namep->parent = parentp; |
| |
| childp->lnkcnt++; |
| |
| unsigned long key = (unsigned long) parentp; |
| hash_table_insert(&childp->names, &key, &namep->link); |
| |
| /* Insert the new node into the namespace. */ |
| if (parentp->child) { |
| tmpfs_dentry_t *tmp = parentp->child; |
| while (tmp->sibling) |
| tmp = tmp->sibling; |
| tmp->sibling = childp; |
| } else { |
| parentp->child = childp; |
| } |
| |
| return true; |
| } |
| |
| int tmpfs_unlink_node(void *prnt, void *chld) |
| { |
| tmpfs_dentry_t *parentp = (tmpfs_dentry_t *)prnt; |
| tmpfs_dentry_t *childp = (tmpfs_dentry_t *)chld; |
| |
| if (!parentp) |
| return EBUSY; |
| |
| if (childp->child) |
| return ENOTEMPTY; |
| |
| if (parentp->child == childp) { |
| parentp->child = childp->sibling; |
| } else { |
| /* TODO: consider doubly linked list for organizing siblings. */ |
| tmpfs_dentry_t *tmp = parentp->child; |
| while (tmp->sibling != childp) |
| tmp = tmp->sibling; |
| tmp->sibling = childp->sibling; |
| } |
| childp->sibling = NULL; |
| |
| unsigned long key = (unsigned long) parentp; |
| hash_table_remove(&childp->names, &key, 1); |
| |
| childp->lnkcnt--; |
| |
| return EOK; |
| } |
| |
| int tmpfs_destroy_node(void *nodep) |
| { |
| tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) nodep; |
| |
| assert(!dentry->lnkcnt); |
| assert(!dentry->child); |
| assert(!dentry->sibling); |
| |
| unsigned long key = dentry->index; |
| hash_table_remove(&dentries, &key, 1); |
| |
| hash_table_destroy(&dentry->names); |
| |
| if (dentry->type == TMPFS_FILE) |
| free(dentry->data); |
| free(dentry); |
| return EOK; |
| } |
| |
| void tmpfs_mounted(ipc_callid_t rid, ipc_call_t *request) |
| { |
| dev_handle_t dev_handle = (dev_handle_t) IPC_GET_ARG1(*request); |
| |
| /* Initialize TMPFS. */ |
| if (!root && !tmpfs_init()) { |
| ipc_answer_0(rid, ENOMEM); |
| return; |
| } |
| |
| if (dev_handle >= 0) { |
| if (tmpfs_restore(dev_handle)) |
| ipc_answer_3(rid, EOK, root->index, root->size, |
| root->lnkcnt); |
| else |
| ipc_answer_0(rid, ELIMIT); |
| } else { |
| ipc_answer_3(rid, EOK, root->index, root->size, root->lnkcnt); |
| } |
| } |
| |
| void tmpfs_mount(ipc_callid_t rid, ipc_call_t *request) |
| { |
| dev_handle_t mp_dev_handle = (dev_handle_t) IPC_GET_ARG1(*request); |
| fs_index_t mp_index = (fs_index_t) IPC_GET_ARG2(*request); |
| fs_handle_t mr_fs_handle = (fs_handle_t) IPC_GET_ARG3(*request); |
| dev_handle_t mr_dev_handle = (dev_handle_t) IPC_GET_ARG4(*request); |
| |
| ipc_answer_0(rid, ENOTSUP); |
| } |
| |
| void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request) |
| { |
| libfs_lookup(&tmpfs_libfs_ops, tmpfs_reg.fs_handle, rid, request); |
| } |
| |
| void tmpfs_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); |
| |
| /* |
| * Lookup the respective dentry. |
| */ |
| link_t *hlp; |
| unsigned long key = index; |
| hlp = hash_table_find(&dentries, &key); |
| if (!hlp) { |
| ipc_answer_0(rid, ENOENT); |
| return; |
| } |
| tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t, |
| dh_link); |
| |
| /* |
| * Receive the read request. |
| */ |
| ipc_callid_t callid; |
| size_t len; |
| if (!ipc_data_read_receive(&callid, &len)) { |
| ipc_answer_0(callid, EINVAL); |
| ipc_answer_0(rid, EINVAL); |
| return; |
| } |
| |
| size_t bytes; |
| if (dentry->type == TMPFS_FILE) { |
| bytes = max(0, min(dentry->size - pos, len)); |
| (void) ipc_data_read_finalize(callid, dentry->data + pos, |
| bytes); |
| } else { |
| int i; |
| tmpfs_dentry_t *cur; |
| |
| assert(dentry->type == TMPFS_DIRECTORY); |
| |
| /* |
| * Yes, we really use O(n) algorithm here. |
| * If it bothers someone, it could be fixed by introducing a |
| * hash table. |
| */ |
| for (i = 0, cur = dentry->child; i < pos && cur; i++, |
| cur = cur->sibling) |
| ; |
| |
| if (!cur) { |
| ipc_answer_0(callid, ENOENT); |
| ipc_answer_1(rid, ENOENT, 0); |
| return; |
| } |
| |
| unsigned long key = (unsigned long) dentry; |
| link_t *hlp = hash_table_find(&cur->names, &key); |
| assert(hlp); |
| tmpfs_name_t *namep = hash_table_get_instance(hlp, tmpfs_name_t, |
| link); |
| |
| (void) ipc_data_read_finalize(callid, namep->name, |
| strlen(namep->name) + 1); |
| bytes = 1; |
| } |
| |
| /* |
| * Answer the VFS_READ call. |
| */ |
| ipc_answer_1(rid, EOK, bytes); |
| } |
| |
| void tmpfs_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); |
| |
| /* |
| * Lookup the respective dentry. |
| */ |
| link_t *hlp; |
| unsigned long key = index; |
| hlp = hash_table_find(&dentries, &key); |
| if (!hlp) { |
| ipc_answer_0(rid, ENOENT); |
| return; |
| } |
| tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t, |
| dh_link); |
| |
| /* |
| * Receive the write request. |
| */ |
| ipc_callid_t callid; |
| size_t len; |
| if (!ipc_data_write_receive(&callid, &len)) { |
| ipc_answer_0(callid, EINVAL); |
| ipc_answer_0(rid, EINVAL); |
| return; |
| } |
| |
| /* |
| * Check whether the file needs to grow. |
| */ |
| if (pos + len <= dentry->size) { |
| /* The file size is not changing. */ |
| (void) ipc_data_write_finalize(callid, dentry->data + pos, len); |
| ipc_answer_2(rid, EOK, len, dentry->size); |
| return; |
| } |
| size_t delta = (pos + len) - dentry->size; |
| /* |
| * At this point, we are deliberately extremely straightforward and |
| * simply realloc the contents of the file on every write that grows the |
| * file. In the end, the situation might not be as bad as it may look: |
| * our heap allocator can save us and just grow the block whenever |
| * possible. |
| */ |
| void *newdata = realloc(dentry->data, dentry->size + delta); |
| if (!newdata) { |
| ipc_answer_0(callid, ENOMEM); |
| ipc_answer_2(rid, EOK, 0, dentry->size); |
| return; |
| } |
| /* Clear any newly allocated memory in order to emulate gaps. */ |
| memset(newdata + dentry->size, 0, delta); |
| dentry->size += delta; |
| dentry->data = newdata; |
| (void) ipc_data_write_finalize(callid, dentry->data + pos, len); |
| ipc_answer_2(rid, EOK, len, dentry->size); |
| } |
| |
| void tmpfs_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); |
| |
| /* |
| * Lookup the respective dentry. |
| */ |
| link_t *hlp; |
| unsigned long key = index; |
| hlp = hash_table_find(&dentries, &key); |
| if (!hlp) { |
| ipc_answer_0(rid, ENOENT); |
| return; |
| } |
| tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t, |
| dh_link); |
| |
| if (size == dentry->size) { |
| ipc_answer_0(rid, EOK); |
| return; |
| } |
| |
| void *newdata = realloc(dentry->data, size); |
| if (!newdata) { |
| ipc_answer_0(rid, ENOMEM); |
| return; |
| } |
| if (size > dentry->size) { |
| size_t delta = size - dentry->size; |
| memset(newdata + dentry->size, 0, delta); |
| } |
| dentry->size = size; |
| dentry->data = newdata; |
| ipc_answer_0(rid, EOK); |
| } |
| |
| void tmpfs_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; |
| |
| link_t *hlp; |
| unsigned long key = index; |
| hlp = hash_table_find(&dentries, &key); |
| if (!hlp) { |
| ipc_answer_0(rid, ENOENT); |
| return; |
| } |
| tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t, |
| dh_link); |
| rc = tmpfs_destroy_node(dentry); |
| ipc_answer_0(rid, rc); |
| } |
| |
| /** |
| * @} |
| */ |