0,0 → 1,627 |
/* |
* 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; |
|
#define TMPFS_DEV 0 /**< Dummy device handle for TMPFS */ |
|
/* |
* 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(dev_handle_t, int); |
static int 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(TMPFS_DEV, 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(dev_handle_t dev_handle, 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; |
} |
|
int 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 ENOMEM; |
tmpfs_name_initialize(namep); |
size_t len = strlen(nm); |
namep->name = malloc(len + 1); |
if (!namep->name) { |
free(namep); |
return ENOMEM; |
} |
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 EOK; |
} |
|
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); |
} |
|
/** |
* @} |
*/ |