0,0 → 1,493 |
/* |
* 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 <dirent.h> |
#include <assert.h> |
#include <sys/types.h> |
#include <libadt/hash_table.h> |
#include <as.h> |
|
#define min(a, b) ((a) < (b) ? (a) : (b)) |
#define max(a, b) ((a) > (b) ? (a) : (b)) |
|
#define PLB_GET_CHAR(i) (tmpfs_reg.plb_ro[(i) % PLB_SIZE]) |
|
#define DENTRIES_BUCKETS 256 |
|
/* |
* Hash table of all directory entries. |
*/ |
hash_table_t dentries; |
|
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 |
}; |
|
unsigned tmpfs_next_index = 1; |
|
static void tmpfs_dentry_initialize(tmpfs_dentry_t *dentry) |
{ |
dentry->index = 0; |
dentry->parent = NULL; |
dentry->sibling = NULL; |
dentry->child = NULL; |
dentry->name = NULL; |
dentry->type = TMPFS_NONE; |
dentry->size = 0; |
dentry->data = NULL; |
link_initialize(&dentry->dh_link); |
} |
|
/* |
* 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; |
|
static bool tmpfs_init(void) |
{ |
if (!hash_table_create(&dentries, DENTRIES_BUCKETS, 1, &dentries_ops)) |
return false; |
|
root = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t)); |
if (!root) |
return false; |
tmpfs_dentry_initialize(root); |
root->index = tmpfs_next_index++; |
root->name = ""; |
root->type = TMPFS_DIRECTORY; |
hash_table_insert(&dentries, &root->index, &root->dh_link); |
|
return true; |
} |
|
/** Compare one component of path to a directory entry. |
* |
* @param dentry Directory entry to compare the path component with. |
* @param component Array of characters holding component name. |
* |
* @return True on match, false otherwise. |
*/ |
static bool match_component(tmpfs_dentry_t *dentry, const char *component) |
{ |
return !strcmp(dentry->name, component); |
} |
|
static unsigned long create_node(tmpfs_dentry_t *dentry, |
const char *component, int lflag) |
{ |
assert(dentry->type == TMPFS_DIRECTORY); |
assert((lflag & L_FILE) ^ (lflag & L_DIRECTORY)); |
|
tmpfs_dentry_t *node = malloc(sizeof(tmpfs_dentry_t)); |
if (!node) |
return 0; |
size_t len = strlen(component); |
char *name = malloc(len + 1); |
if (!name) { |
free(node); |
return 0; |
} |
strcpy(name, component); |
|
tmpfs_dentry_initialize(node); |
node->index = tmpfs_next_index++; |
node->name = name; |
node->parent = dentry; |
if (lflag & L_DIRECTORY) |
node->type = TMPFS_DIRECTORY; |
else |
node->type = TMPFS_FILE; |
|
/* Insert the new node into the namespace. */ |
if (dentry->child) { |
tmpfs_dentry_t *tmp = dentry->child; |
while (tmp->sibling) |
tmp = tmp->sibling; |
tmp->sibling = node; |
} else { |
dentry->child = node; |
} |
|
/* Insert the new node into the dentry hash table. */ |
hash_table_insert(&dentries, &node->index, &node->dh_link); |
return node->index; |
} |
|
static int destroy_component(tmpfs_dentry_t *dentry) |
{ |
return EPERM; |
} |
|
void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request) |
{ |
unsigned next = IPC_GET_ARG1(*request); |
unsigned last = IPC_GET_ARG2(*request); |
int dev_handle = IPC_GET_ARG3(*request); |
int lflag = IPC_GET_ARG4(*request); |
|
if (last < next) |
last += PLB_SIZE; |
|
/* |
* Initialize TMPFS. |
*/ |
if (!root && !tmpfs_init()) { |
ipc_answer_0(rid, ENOMEM); |
return; |
} |
|
tmpfs_dentry_t *dtmp = root->child; |
tmpfs_dentry_t *dcur = root; |
|
if (PLB_GET_CHAR(next) == '/') |
next++; /* eat slash */ |
|
char component[NAME_MAX + 1]; |
int len = 0; |
while (dtmp && next <= last) { |
|
/* collect the component */ |
if (PLB_GET_CHAR(next) != '/') { |
if (len + 1 == NAME_MAX) { |
/* comopnent length overflow */ |
ipc_answer_0(rid, ENAMETOOLONG); |
return; |
} |
component[len++] = PLB_GET_CHAR(next); |
next++; /* process next character */ |
if (next <= last) |
continue; |
} |
|
assert(len); |
component[len] = '\0'; |
next++; /* eat slash */ |
len = 0; |
|
/* match the component */ |
while (dtmp && !match_component(dtmp, component)) |
dtmp = dtmp->sibling; |
|
/* handle miss: match amongst siblings */ |
if (!dtmp) { |
if ((next > last) && (lflag & L_CREATE)) { |
/* no components left and L_CREATE specified */ |
if (dcur->type != TMPFS_DIRECTORY) { |
ipc_answer_0(rid, ENOTDIR); |
return; |
} |
unsigned long index = create_node(dcur, |
component, lflag); |
if (index > 0) { |
ipc_answer_4(rid, EOK, |
tmpfs_reg.fs_handle, dev_handle, |
index, 0); |
} else { |
ipc_answer_0(rid, ENOSPC); |
} |
return; |
} |
ipc_answer_0(rid, ENOENT); |
return; |
} |
|
/* descend one level */ |
dcur = dtmp; |
dtmp = dtmp->child; |
} |
|
/* handle miss: excessive components */ |
if (!dtmp && next <= last) { |
if (lflag & L_CREATE) { |
if (dcur->type != TMPFS_DIRECTORY) { |
ipc_answer_0(rid, ENOTDIR); |
return; |
} |
|
/* collect next component */ |
while (next <= last) { |
if (PLB_GET_CHAR(next) == '/') { |
/* more than one component */ |
ipc_answer_0(rid, ENOENT); |
return; |
} |
if (len + 1 == NAME_MAX) { |
/* component length overflow */ |
ipc_answer_0(rid, ENAMETOOLONG); |
return; |
} |
component[len++] = PLB_GET_CHAR(next); |
next++; /* process next character */ |
} |
assert(len); |
component[len] = '\0'; |
len = 0; |
|
unsigned long index; |
index = create_node(dcur, component, lflag); |
if (index) { |
ipc_answer_4(rid, EOK, tmpfs_reg.fs_handle, |
dev_handle, index, 0); |
} else { |
ipc_answer_0(rid, ENOSPC); |
} |
return; |
} |
ipc_answer_0(rid, ENOENT); |
return; |
} |
|
/* handle hit */ |
if (lflag & L_DESTROY) { |
int res = destroy_component(dcur); |
ipc_answer_0(rid, res); |
return; |
} |
if ((lflag & (L_CREATE | L_EXCLUSIVE)) == (L_CREATE | L_EXCLUSIVE)) { |
ipc_answer_0(rid, EEXIST); |
return; |
} |
if ((lflag & L_FILE) && (dcur->type != TMPFS_FILE)) { |
ipc_answer_0(rid, EISDIR); |
return; |
} |
if ((lflag & L_DIRECTORY) && (dcur->type != TMPFS_DIRECTORY)) { |
ipc_answer_0(rid, ENOTDIR); |
return; |
} |
|
ipc_answer_4(rid, EOK, tmpfs_reg.fs_handle, dev_handle, dcur->index, |
dcur->size); |
} |
|
void tmpfs_read(ipc_callid_t rid, ipc_call_t *request) |
{ |
int dev_handle = IPC_GET_ARG1(*request); |
unsigned long index = IPC_GET_ARG2(*request); |
off_t pos = IPC_GET_ARG3(*request); |
|
/* |
* Lookup the respective dentry. |
*/ |
link_t *hlp; |
hlp = hash_table_find(&dentries, &index); |
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 = dentry->child; |
|
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; |
} |
|
(void) ipc_data_read_finalize(callid, cur->name, |
strlen(cur->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) |
{ |
int dev_handle = IPC_GET_ARG1(*request); |
unsigned long index = IPC_GET_ARG2(*request); |
off_t pos = IPC_GET_ARG3(*request); |
|
/* |
* Lookup the respective dentry. |
*/ |
link_t *hlp; |
hlp = hash_table_find(&dentries, &index); |
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) |
{ |
int dev_handle = IPC_GET_ARG1(*request); |
unsigned long index = IPC_GET_ARG2(*request); |
size_t size = IPC_GET_ARG3(*request); |
|
/* |
* Lookup the respective dentry. |
*/ |
link_t *hlp; |
hlp = hash_table_find(&dentries, &index); |
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); |
} |
|
/** |
* @} |
*/ |