/*
* 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 NODES_BUCKETS 256
/** All root nodes have index 0. */
#define TMPFS_SOME_ROOT 0
/** Global counter for assigning node indices. Shared by all instances. */
fs_index_t tmpfs_next_index = 1;
/*
* Implementation of the libfs interface.
*/
/* Forward declarations of static functions. */
static fs_node_t *tmpfs_match(fs_node_t *, const char *);
static fs_node_t *tmpfs_node_get(dev_handle_t, fs_index_t);
static void tmpfs_node_put(fs_node_t *);
static fs_node_t *tmpfs_create_node(dev_handle_t, int);
static int tmpfs_link_node(fs_node_t *, fs_node_t *, const char *);
static int tmpfs_unlink_node(fs_node_t *, fs_node_t *, const char *);
static int tmpfs_destroy_node(fs_node_t *);
/* Implementation of helper functions. */
static fs_index_t tmpfs_index_get(fs_node_t *fn)
{
return TMPFS_NODE(fn)->index;
}
static size_t tmpfs_size_get(fs_node_t *fn)
{
return TMPFS_NODE(fn)->size;
}
static unsigned tmpfs_lnkcnt_get(fs_node_t *fn)
{
return TMPFS_NODE(fn)->lnkcnt;
}
static bool tmpfs_has_children(fs_node_t *fn)
{
return !list_empty(&TMPFS_NODE(fn)->cs_head);
}
static fs_node_t *tmpfs_root_get(dev_handle_t dev_handle)
{
return tmpfs_node_get(dev_handle, TMPFS_SOME_ROOT);
}
static char tmpfs_plb_get_char(unsigned pos)
{
return tmpfs_reg.plb_ro[pos % PLB_SIZE];
}
static bool tmpfs_is_directory(fs_node_t *fn)
{
return TMPFS_NODE(fn)->type == TMPFS_DIRECTORY;
}
static bool tmpfs_is_file(fs_node_t *fn)
{
return TMPFS_NODE(fn)->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 TMPFS nodes. */
hash_table_t nodes;
#define NODES_KEY_INDEX 0
#define NODES_KEY_DEV 1
/* Implementation of hash table interface for the nodes hash table. */
static hash_index_t nodes_hash(unsigned long key[])
{
return key[NODES_KEY_INDEX] % NODES_BUCKETS;
}
static int nodes_compare(unsigned long key[], hash_count_t keys, link_t *item)
{
tmpfs_node_t *nodep = hash_table_get_instance(item, tmpfs_node_t,
nh_link);
return (nodep->index == key[NODES_KEY_INDEX] &&
nodep->dev_handle == key[NODES_KEY_DEV]);
}
static void nodes_remove_callback(link_t *item)
{
}
/** TMPFS nodes hash table operations. */
hash_table_operations_t nodes_ops = {
.hash = nodes_hash,
.compare = nodes_compare,
.remove_callback = nodes_remove_callback
};
static void tmpfs_node_initialize(tmpfs_node_t *nodep)
{
nodep->bp = NULL;
nodep->index = 0;
nodep->dev_handle = 0;
nodep->type = TMPFS_NONE;
nodep->lnkcnt = 0;
nodep->size = 0;
nodep->data = NULL;
link_initialize(&nodep->nh_link);
list_initialize(&nodep->cs_head);
}
static void tmpfs_dentry_initialize(tmpfs_dentry_t *dentryp)
{
link_initialize(&dentryp->link);
dentryp->name = NULL;
dentryp->node = NULL;
}
bool tmpfs_init(void)
{
if (!hash_table_create(&nodes, NODES_BUCKETS, 2, &nodes_ops))
return false;
return true;
}
static bool tmpfs_instance_init(dev_handle_t dev_handle)
{
fs_node_t *rfn;
rfn = tmpfs_create_node(dev_handle, L_DIRECTORY);
if (!rfn)
return false;
TMPFS_NODE(rfn)->lnkcnt = 0; /* FS root is not linked */
return true;
}
fs_node_t *tmpfs_match(fs_node_t *pfn, const char *component)
{
tmpfs_node_t *parentp = TMPFS_NODE(pfn);
link_t *lnk;
for (lnk = parentp->cs_head.next; lnk != &parentp->cs_head;
lnk = lnk->next) {
tmpfs_dentry_t *dentryp = list_get_instance(lnk, tmpfs_dentry_t,
link);
if (!str_cmp(dentryp->name, component))
return FS_NODE(dentryp->node);
}
return NULL;
}
fs_node_t *tmpfs_node_get(dev_handle_t dev_handle, fs_index_t index)
{
unsigned long key[] = {
[NODES_KEY_INDEX] = index,
[NODES_KEY_DEV] = dev_handle
};
link_t *lnk = hash_table_find(&nodes, key);
if (!lnk)
return NULL;
return FS_NODE(hash_table_get_instance(lnk, tmpfs_node_t, nh_link));
}
void tmpfs_node_put(fs_node_t *fn)
{
/* nothing to do */
}
fs_node_t *tmpfs_create_node(dev_handle_t dev_handle, int lflag)
{
assert((lflag
& L_FILE
) ^ (lflag
& L_DIRECTORY
));
tmpfs_node_t
*nodep
= malloc(sizeof(tmpfs_node_t
)); if (!nodep)
return NULL;
tmpfs_node_initialize(nodep);
nodep
->bp
= malloc(sizeof(fs_node_t
)); if (!nodep->bp) {
return NULL;
}
fs_node_initialize(nodep->bp);
nodep->bp->data = nodep; /* link the FS and TMPFS nodes */
if (!tmpfs_root_get(dev_handle))
nodep->index = TMPFS_SOME_ROOT;
else
nodep->index = tmpfs_next_index++;
nodep->dev_handle = dev_handle;
if (lflag & L_DIRECTORY)
nodep->type = TMPFS_DIRECTORY;
else
nodep->type = TMPFS_FILE;
/* Insert the new node into the nodes hash table. */
unsigned long key[] = {
[NODES_KEY_INDEX] = nodep->index,
[NODES_KEY_DEV] = nodep->dev_handle
};
hash_table_insert(&nodes, key, &nodep->nh_link);
return FS_NODE(nodep);
}
int tmpfs_link_node(fs_node_t *pfn, fs_node_t *cfn, const char *nm)
{
tmpfs_node_t *parentp = TMPFS_NODE(pfn);
tmpfs_node_t *childp = TMPFS_NODE(cfn);
tmpfs_dentry_t *dentryp;
link_t *lnk;
assert(parentp
->type
== TMPFS_DIRECTORY
);
/* Check for duplicit entries. */
for (lnk = parentp->cs_head.next; lnk != &parentp->cs_head;
lnk = lnk->next) {
dentryp = list_get_instance(lnk, tmpfs_dentry_t, link);
if (!str_cmp(dentryp->name, nm))
return EEXIST;
}
/* Allocate and initialize the dentry. */
dentryp
= malloc(sizeof(tmpfs_dentry_t
)); if (!dentryp)
return ENOMEM;
tmpfs_dentry_initialize(dentryp);
/* Populate and link the new dentry. */
size_t size = str_size(nm);
dentryp
->name
= malloc(size
+ 1); if (!dentryp->name) {
return ENOMEM;
}
str_cpy(dentryp->name, size + 1, nm);
dentryp->node = childp;
childp->lnkcnt++;
list_append(&dentryp->link, &parentp->cs_head);
return EOK;
}
int tmpfs_unlink_node(fs_node_t *pfn, fs_node_t *cfn, const char *nm)
{
tmpfs_node_t *parentp = TMPFS_NODE(pfn);
tmpfs_node_t *childp = NULL;
tmpfs_dentry_t *dentryp;
link_t *lnk;
if (!parentp)
return EBUSY;
for (lnk = parentp->cs_head.next; lnk != &parentp->cs_head;
lnk = lnk->next) {
dentryp = list_get_instance(lnk, tmpfs_dentry_t, link);
if (!str_cmp(dentryp->name, nm)) {
childp = dentryp->node;
assert(FS_NODE
(childp
) == cfn
); break;
}
}
if (!childp)
return ENOENT;
if ((childp->lnkcnt == 1) && !list_empty(&childp->cs_head))
return ENOTEMPTY;
list_remove(&dentryp->link);
childp->lnkcnt--;
return EOK;
}
int tmpfs_destroy_node(fs_node_t *fn)
{
tmpfs_node_t *nodep = TMPFS_NODE(fn);
assert(list_empty
(&nodep
->cs_head
));
unsigned long key[] = {
[NODES_KEY_INDEX] = nodep->index,
[NODES_KEY_DEV] = nodep->dev_handle
};
hash_table_remove(&nodes, key, 2);
if (nodep->type == TMPFS_FILE)
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);
/* accept the mount options */
ipc_callid_t callid;
size_t size;
if (!ipc_data_write_receive(&callid, &size)) {
ipc_answer_0(callid, EINVAL);
ipc_answer_0(rid, EINVAL);
return;
}
char *opts
= malloc(size
+ 1); if (!opts) {
ipc_answer_0(callid, ENOMEM);
ipc_answer_0(rid, ENOMEM);
return;
}
ipcarg_t retval = ipc_data_write_finalize(callid, opts, size);
if (retval != EOK) {
ipc_answer_0(rid, retval);
return;
}
opts[size] = '\0';
/* Initialize TMPFS instance. */
if (!tmpfs_instance_init(dev_handle)) {
ipc_answer_0(rid, ENOMEM);
return;
}
tmpfs_node_t *rootp = TMPFS_NODE(tmpfs_root_get(dev_handle));
if (str_cmp(opts, "restore") == 0) {
if (tmpfs_restore(dev_handle))
ipc_answer_3(rid, EOK, rootp->index, rootp->size,
rootp->lnkcnt);
else
ipc_answer_0(rid, ELIMIT);
} else {
ipc_answer_3(rid, EOK, rootp->index, rootp->size,
rootp->lnkcnt);
}
}
void tmpfs_mount(ipc_callid_t rid, ipc_call_t *request)
{
libfs_mount(&tmpfs_libfs_ops, rid, request);
}
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 TMPFS node.
*/
link_t *hlp;
unsigned long key[] = {
[NODES_KEY_INDEX] = index,
[NODES_KEY_DEV] = dev_handle,
};
hlp = hash_table_find(&nodes, key);
if (!hlp) {
ipc_answer_0(rid, ENOENT);
return;
}
tmpfs_node_t *nodep = hash_table_get_instance(hlp, tmpfs_node_t,
nh_link);
/*
* Receive the read request.
*/
ipc_callid_t callid;
size_t size;
if (!ipc_data_read_receive(&callid, &size)) {
ipc_answer_0(callid, EINVAL);
ipc_answer_0(rid, EINVAL);
return;
}
size_t bytes;
if (nodep->type == TMPFS_FILE) {
bytes = max(0, min(nodep->size - pos, size));
(void) ipc_data_read_finalize(callid, nodep->data + pos,
bytes);
} else {
tmpfs_dentry_t *dentryp;
link_t *lnk;
int i;
assert(nodep
->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, lnk = nodep->cs_head.next;
i < pos && lnk != &nodep->cs_head;
i++, lnk = lnk->next)
;
if (lnk == &nodep->cs_head) {
ipc_answer_0(callid, ENOENT);
ipc_answer_1(rid, ENOENT, 0);
return;
}
dentryp = list_get_instance(lnk, tmpfs_dentry_t, link);
(void) ipc_data_read_finalize(callid, dentryp->name,
str_size(dentryp->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 TMPFS node.
*/
link_t *hlp;
unsigned long key[] = {
[NODES_KEY_INDEX] = index,
[NODES_KEY_DEV] = dev_handle
};
hlp = hash_table_find(&nodes, key);
if (!hlp) {
ipc_answer_0(rid, ENOENT);
return;
}
tmpfs_node_t *nodep = hash_table_get_instance(hlp, tmpfs_node_t,
nh_link);
/*
* Receive the write request.
*/
ipc_callid_t callid;
size_t size;
if (!ipc_data_write_receive(&callid, &size)) {
ipc_answer_0(callid, EINVAL);
ipc_answer_0(rid, EINVAL);
return;
}
/*
* Check whether the file needs to grow.
*/
if (pos + size <= nodep->size) {
/* The file size is not changing. */
(void) ipc_data_write_finalize(callid, nodep->data + pos, size);
ipc_answer_2(rid, EOK, size, nodep->size);
return;
}
size_t delta = (pos + size) - nodep->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(nodep
->data
, nodep
->size
+ delta
); if (!newdata) {
ipc_answer_0(callid, ENOMEM);
ipc_answer_2(rid, EOK, 0, nodep->size);
return;
}
/* Clear any newly allocated memory in order to emulate gaps. */
memset(newdata
+ nodep
->size
, 0, delta
); nodep->size += delta;
nodep->data = newdata;
(void) ipc_data_write_finalize(callid, nodep->data + pos, size);
ipc_answer_2(rid, EOK, size, nodep->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 TMPFS node.
*/
link_t *hlp;
unsigned long key[] = {
[NODES_KEY_INDEX] = index,
[NODES_KEY_DEV] = dev_handle
};
hlp = hash_table_find(&nodes, key);
if (!hlp) {
ipc_answer_0(rid, ENOENT);
return;
}
tmpfs_node_t *nodep = hash_table_get_instance(hlp, tmpfs_node_t,
nh_link);
if (size == nodep->size) {
ipc_answer_0(rid, EOK);
return;
}
void *newdata
= realloc(nodep
->data
, size
); if (!newdata) {
ipc_answer_0(rid, ENOMEM);
return;
}
if (size > nodep->size) {
size_t delta = size - nodep->size;
memset(newdata
+ nodep
->size
, 0, delta
); }
nodep->size = size;
nodep->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[] = {
[NODES_KEY_INDEX] = index,
[NODES_KEY_DEV] = dev_handle
};
hlp = hash_table_find(&nodes, key);
if (!hlp) {
ipc_answer_0(rid, ENOENT);
return;
}
tmpfs_node_t *nodep = hash_table_get_instance(hlp, tmpfs_node_t,
nh_link);
rc = tmpfs_destroy_node(FS_NODE(nodep));
ipc_answer_0(rid, rc);
}
/**
* @}
*/