WebSVN – HelenOS – Diff – /trunk/uspace/srv/fs/tmpfs/tmpfs_ops.c


/*
 * 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
 
/*
 * 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 bool tmpfs_match(void *, const char *);
static void *tmpfs_create_node(int);
static bool tmpfs_link_node(void *, void *, const char *);
static int tmpfs_unlink_node(void *);
static void tmpfs_destroy_node(void *);
 
/* Implementation of helper functions. */
static unsigned long tmpfs_index_get(void *nodep)
{
    return ((tmpfs_dentry_t *) nodep)->index;
}
 
static unsigned long 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 void *tmpfs_child_get(void *nodep)
{
    return ((tmpfs_dentry_t *) nodep)->child;
}
 
static void *tmpfs_sibling_get(void *nodep)
{
    return ((tmpfs_dentry_t *) nodep)->sibling;
}
 
static void *tmpfs_root_get(void)
{
    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,
    .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,
    .child_get = tmpfs_child_get,
    .sibling_get = tmpfs_sibling_get,
    .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. */
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->lnkcnt = 0;
    dentry->size = 0;
    dentry->data = NULL;
    link_initialize(&dentry->dh_link);
}
 
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);
    root->lnkcnt = 1;
    return root != NULL;
}
 
/** Compare one component of path to a directory entry.
 *
 * @param nodep     Node to compare the path component with.
 * @param component Array of characters holding component name.
 *
 * @return      True on match, false otherwise.
 */
bool tmpfs_match(void *nodep, const char *component)
{
    tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) nodep;
 
    return !strcmp(dentry->name, component);
}
 
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;
 
    tmpfs_dentry_initialize(node);
    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. */
    hash_table_insert(&dentries, &node->index, &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);
 
    size_t len = strlen(nm);
    char *name = malloc(len + 1);
    if (!name)
        return false;
   
    childp->lnkcnt++;
   
    strcpy(name, nm);
    childp->name = name;
 
    /* 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;
    }
    childp->parent = parentp;
 
    return true;
}
 
int tmpfs_unlink_node(void *nodeptr)
{
    tmpfs_dentry_t *dentry = (tmpfs_dentry_t *)nodeptr;
 
    if (dentry->child)
        return ENOTEMPTY;
 
    if (!dentry->parent)
        return EBUSY;
 
    if (dentry->parent->child == dentry) {
        dentry->parent->child = dentry->sibling;
    } else {
        /* TODO: consider doubly linked list for organizing siblings. */
        tmpfs_dentry_t *tmp = dentry->parent->child;
        while (tmp->sibling != dentry)
            tmp = tmp->sibling;
        tmp->sibling = dentry->sibling;
    }
    dentry->sibling = NULL;
    dentry->parent = NULL;
 
    free(dentry->name);
    dentry->name = NULL;
 
    dentry->lnkcnt--;
 
    return EOK;
}
 
void tmpfs_destroy_node(void *nodep)
{
    tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) nodep;
   
    assert(!dentry->lnkcnt);
    assert(!dentry->child);
    assert(!dentry->sibling);
 
    unsigned long index = dentry->index;
    hash_table_remove(&dentries, &index, 1);
 
    if (dentry->type == TMPFS_FILE)
        free(dentry->data);
    free(dentry);
}
 
void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request)
{
    /* Initialize TMPFS. */
    if (!root && !tmpfs_init()) {
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    libfs_lookup(&tmpfs_libfs_ops, tmpfs_reg.fs_handle, rid, request);
}
 
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;
       
        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);
}
 
void tmpfs_destroy(ipc_callid_t rid, ipc_call_t *request)
{
    int dev_handle = IPC_GET_ARG1(*request);
    unsigned long index = IPC_GET_ARG2(*request);
 
    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);
    tmpfs_destroy_node(dentry);
    ipc_answer_0(rid, EOK);
}
 
/**
 * @}
 */
 

Rev 2756	Rev 2757
1	/*	1	/*
2	* Copyright (c) 2008 Jakub Jermar	2	* Copyright (c) 2008 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/** @addtogroup fs	29	/** @addtogroup fs
30	* @{	30	* @{
31	*/	31	*/
32		32
33	/**	33	/**
34	* @file tmpfs_ops.c	34	* @file tmpfs_ops.c
35	* @brief Implementation of VFS operations for the TMPFS file system	35	* @brief Implementation of VFS operations for the TMPFS file system
36	* server.	36	* server.
37	*/	37	*/
38		38
39	#include "tmpfs.h"	39	#include "tmpfs.h"
40	#include "../../vfs/vfs.h"	40	#include "../../vfs/vfs.h"
41	#include <ipc/ipc.h>	41	#include <ipc/ipc.h>
42	#include <async.h>	42	#include <async.h>
43	#include <errno.h>	43	#include <errno.h>
44	#include <atomic.h>	44	#include <atomic.h>
45	#include <stdlib.h>	45	#include <stdlib.h>
46	#include <string.h>	46	#include <string.h>
47	#include <stdio.h>	47	#include <stdio.h>
48	#include <assert.h>	48	#include <assert.h>
49	#include <sys/types.h>	49	#include <sys/types.h>
50	#include <libadt/hash_table.h>	50	#include <libadt/hash_table.h>
51	#include <as.h>	51	#include <as.h>
52	#include <libfs.h>	52	#include <libfs.h>
53		53
54	#define min(a, b) ((a) < (b) ? (a) : (b))	54	#define min(a, b) ((a) < (b) ? (a) : (b))
55	#define max(a, b) ((a) > (b) ? (a) : (b))	55	#define max(a, b) ((a) > (b) ? (a) : (b))
56		56
57	#define DENTRIES_BUCKETS 256	57	#define DENTRIES_BUCKETS 256
58		58
59	/*	59	/*
60	* For now, we don't distinguish between different dev_handles/instances. All	60	* For now, we don't distinguish between different dev_handles/instances. All
61	* requests resolve to the only instance, rooted in the following variable.	61	* requests resolve to the only instance, rooted in the following variable.
62	*/	62	*/
63	static tmpfs_dentry_t *root;	63	static tmpfs_dentry_t *root;
64		64
65	/*	65	/*
66	* Implementation of the libfs interface.	66	* Implementation of the libfs interface.
67	*/	67	*/
68		68
69	/* Forward declarations of static functions. */	69	/* Forward declarations of static functions. */
70	static bool tmpfs_match(void , const char );	70	static bool tmpfs_match(void , const char );
71	static void *tmpfs_create_node(int);	71	static void *tmpfs_create_node(int);
72	static bool tmpfs_link_node(void , void , const char *);	72	static bool tmpfs_link_node(void , void , const char *);
73	static int tmpfs_unlink_node(void *);	73	static int tmpfs_unlink_node(void *);
74	static void tmpfs_destroy_node(void *);	74	static void tmpfs_destroy_node(void *);
75		75
76	/* Implementation of helper functions. */	76	/* Implementation of helper functions. */
77	static unsigned long tmpfs_index_get(void *nodep)	77	static unsigned long tmpfs_index_get(void *nodep)
78	{	78	{
79	return ((tmpfs_dentry_t *) nodep)->index;	79	return ((tmpfs_dentry_t *) nodep)->index;
80	}	80	}
81		81
82	static unsigned long tmpfs_size_get(void *nodep)	82	static unsigned long tmpfs_size_get(void *nodep)
83	{	83	{
84	return ((tmpfs_dentry_t *) nodep)->size;	84	return ((tmpfs_dentry_t *) nodep)->size;
85	}	85	}
86		86
87	static unsigned tmpfs_lnkcnt_get(void *nodep)	87	static unsigned tmpfs_lnkcnt_get(void *nodep)
88	{	88	{
89	return ((tmpfs_dentry_t *) nodep)->lnkcnt;	89	return ((tmpfs_dentry_t *) nodep)->lnkcnt;
90	}	90	}
91		91
92	static void tmpfs_child_get(void nodep)	92	static void tmpfs_child_get(void nodep)
93	{	93	{
94	return ((tmpfs_dentry_t *) nodep)->child;	94	return ((tmpfs_dentry_t *) nodep)->child;
95	}	95	}
96		96
97	static void tmpfs_sibling_get(void nodep)	97	static void tmpfs_sibling_get(void nodep)
98	{	98	{
99	return ((tmpfs_dentry_t *) nodep)->sibling;	99	return ((tmpfs_dentry_t *) nodep)->sibling;
100	}	100	}
101		101
102	static void *tmpfs_root_get(void)	102	static void *tmpfs_root_get(void)
103	{	103	{
104	return root;	104	return root;
105	}	105	}
106		106
107	static char tmpfs_plb_get_char(unsigned pos)	107	static char tmpfs_plb_get_char(unsigned pos)
108	{	108	{
109	return tmpfs_reg.plb_ro[pos % PLB_SIZE];	109	return tmpfs_reg.plb_ro[pos % PLB_SIZE];
110	}	110	}
111		111
112	static bool tmpfs_is_directory(void *nodep)	112	static bool tmpfs_is_directory(void *nodep)
113	{	113	{
114	return ((tmpfs_dentry_t *) nodep)->type == TMPFS_DIRECTORY;	114	return ((tmpfs_dentry_t *) nodep)->type == TMPFS_DIRECTORY;
115	}	115	}
116		116
117	static bool tmpfs_is_file(void *nodep)	117	static bool tmpfs_is_file(void *nodep)
118	{	118	{
119	return ((tmpfs_dentry_t *) nodep)->type == TMPFS_FILE;	119	return ((tmpfs_dentry_t *) nodep)->type == TMPFS_FILE;
120	}	120	}
121		121
122	/** libfs operations */	122	/** libfs operations */
123	libfs_ops_t tmpfs_libfs_ops = {	123	libfs_ops_t tmpfs_libfs_ops = {
124	.match = tmpfs_match,	124	.match = tmpfs_match,
125	.create = tmpfs_create_node,	125	.create = tmpfs_create_node,
126	.destroy = tmpfs_destroy_node,	126	.destroy = tmpfs_destroy_node,
127	.link = tmpfs_link_node,	127	.link = tmpfs_link_node,
128	.unlink = tmpfs_unlink_node,	128	.unlink = tmpfs_unlink_node,
129	.index_get = tmpfs_index_get,	129	.index_get = tmpfs_index_get,
130	.size_get = tmpfs_size_get,	130	.size_get = tmpfs_size_get,
131	.lnkcnt_get = tmpfs_lnkcnt_get,	131	.lnkcnt_get = tmpfs_lnkcnt_get,
132	.child_get = tmpfs_child_get,	132	.child_get = tmpfs_child_get,
133	.sibling_get = tmpfs_sibling_get,	133	.sibling_get = tmpfs_sibling_get,
134	.root_get = tmpfs_root_get,	134	.root_get = tmpfs_root_get,
135	.plb_get_char = tmpfs_plb_get_char,	135	.plb_get_char = tmpfs_plb_get_char,
136	.is_directory = tmpfs_is_directory,	136	.is_directory = tmpfs_is_directory,
137	.is_file = tmpfs_is_file	137	.is_file = tmpfs_is_file
138	};	138	};
139		139
140	/** Hash table of all directory entries. */	140	/** Hash table of all directory entries. */
141	hash_table_t dentries;	141	hash_table_t dentries;
142		142
143	/* Implementation of hash table interface. */	143	/* Implementation of hash table interface. */
144	static hash_index_t dentries_hash(unsigned long *key)	144	static hash_index_t dentries_hash(unsigned long *key)
145	{	145	{
146	return *key % DENTRIES_BUCKETS;	146	return *key % DENTRIES_BUCKETS;
147	}	147	}
148		148
149	static int dentries_compare(unsigned long *key, hash_count_t keys,	149	static int dentries_compare(unsigned long *key, hash_count_t keys,
150	link_t *item)	150	link_t *item)
151	{	151	{
152	tmpfs_dentry_t *dentry = hash_table_get_instance(item, tmpfs_dentry_t,	152	tmpfs_dentry_t *dentry = hash_table_get_instance(item, tmpfs_dentry_t,
153	dh_link);	153	dh_link);
154	return dentry->index == *key;	154	return dentry->index == *key;
155	}	155	}
156		156
157	static void dentries_remove_callback(link_t *item)	157	static void dentries_remove_callback(link_t *item)
158	{	158	{
159	}	159	}
160		160
161	/** TMPFS dentries hash table operations. */	161	/** TMPFS dentries hash table operations. */
162	hash_table_operations_t dentries_ops = {	162	hash_table_operations_t dentries_ops = {
163	.hash = dentries_hash,	163	.hash = dentries_hash,
164	.compare = dentries_compare,	164	.compare = dentries_compare,
165	.remove_callback = dentries_remove_callback	165	.remove_callback = dentries_remove_callback
166	};	166	};
167		167
168	unsigned tmpfs_next_index = 1;	168	unsigned tmpfs_next_index = 1;
169		169
170	static void tmpfs_dentry_initialize(tmpfs_dentry_t *dentry)	170	static void tmpfs_dentry_initialize(tmpfs_dentry_t *dentry)
171	{	171	{
172	dentry->index = 0;	172	dentry->index = 0;
173	dentry->parent = NULL;	173	dentry->parent = NULL;
174	dentry->sibling = NULL;	174	dentry->sibling = NULL;
175	dentry->child = NULL;	175	dentry->child = NULL;
176	dentry->name = NULL;	176	dentry->name = NULL;
177	dentry->type = TMPFS_NONE;	177	dentry->type = TMPFS_NONE;
178	dentry->lnkcnt = 0;	178	dentry->lnkcnt = 0;
179	dentry->size = 0;	179	dentry->size = 0;
180	dentry->data = NULL;	180	dentry->data = NULL;
181	link_initialize(&dentry->dh_link);	181	link_initialize(&dentry->dh_link);
182	}	182	}
183		183
184	static bool tmpfs_init(void)	184	static bool tmpfs_init(void)
185	{	185	{
186	if (!hash_table_create(&dentries, DENTRIES_BUCKETS, 1, &dentries_ops))	186	if (!hash_table_create(&dentries, DENTRIES_BUCKETS, 1, &dentries_ops))
187	return false;	187	return false;
188	root = (tmpfs_dentry_t *) tmpfs_create_node(L_DIRECTORY);	188	root = (tmpfs_dentry_t *) tmpfs_create_node(L_DIRECTORY);
-		189	root->lnkcnt = 1;
189	return root != NULL;	190	return root != NULL;
190	}	191	}
191		192
192	/** Compare one component of path to a directory entry.	193	/** Compare one component of path to a directory entry.
193	*	194	*
194	* @param nodep Node to compare the path component with.	195	* @param nodep Node to compare the path component with.
195	* @param component Array of characters holding component name.	196	* @param component Array of characters holding component name.
196	*	197	*
197	* @return True on match, false otherwise.	198	* @return True on match, false otherwise.
198	*/	199	*/
199	bool tmpfs_match(void nodep, const char component)	200	bool tmpfs_match(void nodep, const char component)
200	{	201	{
201	tmpfs_dentry_t dentry = (tmpfs_dentry_t ) nodep;	202	tmpfs_dentry_t dentry = (tmpfs_dentry_t ) nodep;
202		203
203	return !strcmp(dentry->name, component);	204	return !strcmp(dentry->name, component);
204	}	205	}
205		206
206	void *tmpfs_create_node(int lflag)	207	void *tmpfs_create_node(int lflag)
207	{	208	{
208	assert((lflag & L_FILE) ^ (lflag & L_DIRECTORY));	209	assert((lflag & L_FILE) ^ (lflag & L_DIRECTORY));
209		210
210	tmpfs_dentry_t *node = malloc(sizeof(tmpfs_dentry_t));	211	tmpfs_dentry_t *node = malloc(sizeof(tmpfs_dentry_t));
211	if (!node)	212	if (!node)
212	return NULL;	213	return NULL;
213		214
214	tmpfs_dentry_initialize(node);	215	tmpfs_dentry_initialize(node);
215	node->index = tmpfs_next_index++;	216	node->index = tmpfs_next_index++;
216	if (lflag & L_DIRECTORY)	217	if (lflag & L_DIRECTORY)
217	node->type = TMPFS_DIRECTORY;	218	node->type = TMPFS_DIRECTORY;
218	else	219	else
219	node->type = TMPFS_FILE;	220	node->type = TMPFS_FILE;
220		221
221	/* Insert the new node into the dentry hash table. */	222	/* Insert the new node into the dentry hash table. */
222	hash_table_insert(&dentries, &node->index, &node->dh_link);	223	hash_table_insert(&dentries, &node->index, &node->dh_link);
223	return (void *) node;	224	return (void *) node;
224	}	225	}
225		226
226	bool tmpfs_link_node(void prnt, void chld, const char *nm)	227	bool tmpfs_link_node(void prnt, void chld, const char *nm)
227	{	228	{
228	tmpfs_dentry_t parentp = (tmpfs_dentry_t ) prnt;	229	tmpfs_dentry_t parentp = (tmpfs_dentry_t ) prnt;
229	tmpfs_dentry_t childp = (tmpfs_dentry_t ) chld;	230	tmpfs_dentry_t childp = (tmpfs_dentry_t ) chld;
230		231
231	assert(parentp->type == TMPFS_DIRECTORY);	232	assert(parentp->type == TMPFS_DIRECTORY);
232		233
233	size_t len = strlen(nm);	234	size_t len = strlen(nm);
234	char *name = malloc(len + 1);	235	char *name = malloc(len + 1);
235	if (!name)	236	if (!name)
236	return false;	237	return false;
237		238
238	childp->lnkcnt++;	239	childp->lnkcnt++;
239		240
240	strcpy(name, nm);	241	strcpy(name, nm);
241	childp->name = name;	242	childp->name = name;
242		243
243	/* Insert the new node into the namespace. */	244	/* Insert the new node into the namespace. */
244	if (parentp->child) {	245	if (parentp->child) {
245	tmpfs_dentry_t *tmp = parentp->child;	246	tmpfs_dentry_t *tmp = parentp->child;
246	while (tmp->sibling)	247	while (tmp->sibling)
247	tmp = tmp->sibling;	248	tmp = tmp->sibling;
248	tmp->sibling = childp;	249	tmp->sibling = childp;
249	} else {	250	} else {
250	parentp->child = childp;	251	parentp->child = childp;
251	}	252	}
252	childp->parent = parentp;	253	childp->parent = parentp;
253		254
254	return true;	255	return true;
255	}	256	}
256		257
257	int tmpfs_unlink_node(void *nodeptr)	258	int tmpfs_unlink_node(void *nodeptr)
258	{	259	{
259	tmpfs_dentry_t dentry = (tmpfs_dentry_t )nodeptr;	260	tmpfs_dentry_t dentry = (tmpfs_dentry_t )nodeptr;
260		261
261	if (dentry->child)	262	if (dentry->child)
262	return ENOTEMPTY;	263	return ENOTEMPTY;
263		264
264	if (!dentry->parent)	265	if (!dentry->parent)
265	return EBUSY;	266	return EBUSY;
266		267
267	if (dentry->parent->child == dentry) {	268	if (dentry->parent->child == dentry) {
268	dentry->parent->child = dentry->sibling;	269	dentry->parent->child = dentry->sibling;
269	} else {	270	} else {
270	/* TODO: consider doubly linked list for organizing siblings. */	271	/* TODO: consider doubly linked list for organizing siblings. */
271	tmpfs_dentry_t *tmp = dentry->parent->child;	272	tmpfs_dentry_t *tmp = dentry->parent->child;
272	while (tmp->sibling != dentry)	273	while (tmp->sibling != dentry)
273	tmp = tmp->sibling;	274	tmp = tmp->sibling;
274	tmp->sibling = dentry->sibling;	275	tmp->sibling = dentry->sibling;
275	}	276	}
276	dentry->sibling = NULL;	277	dentry->sibling = NULL;
277	dentry->parent = NULL;	278	dentry->parent = NULL;
278		279
279	free(dentry->name);	280	free(dentry->name);
280	dentry->name = NULL;	281	dentry->name = NULL;
281		282
282	dentry->lnkcnt--;	283	dentry->lnkcnt--;
283		284
284	return EOK;	285	return EOK;
285	}	286	}
286		287
287	void tmpfs_destroy_node(void *nodep)	288	void tmpfs_destroy_node(void *nodep)
288	{	289	{
289	tmpfs_dentry_t dentry = (tmpfs_dentry_t ) nodep;	290	tmpfs_dentry_t dentry = (tmpfs_dentry_t ) nodep;
290		291
291	assert(!dentry->lnkcnt);	292	assert(!dentry->lnkcnt);
292	assert(!dentry->child);	293	assert(!dentry->child);
293	assert(!dentry->sibling);	294	assert(!dentry->sibling);
294		295
295	unsigned long index = dentry->index;	296	unsigned long index = dentry->index;
296	hash_table_remove(&dentries, &index, 1);	297	hash_table_remove(&dentries, &index, 1);
297		298
298	if (dentry->type == TMPFS_FILE)	299	if (dentry->type == TMPFS_FILE)
299	free(dentry->data);	300	free(dentry->data);
300	free(dentry);	301	free(dentry);
301	}	302	}
302		303
303	void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request)	304	void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request)
304	{	305	{
305	/* Initialize TMPFS. */	306	/* Initialize TMPFS. */
306	if (!root && !tmpfs_init()) {	307	if (!root && !tmpfs_init()) {
307	ipc_answer_0(rid, ENOMEM);	308	ipc_answer_0(rid, ENOMEM);
308	return;	309	return;
309	}	310	}
310	libfs_lookup(&tmpfs_libfs_ops, tmpfs_reg.fs_handle, rid, request);	311	libfs_lookup(&tmpfs_libfs_ops, tmpfs_reg.fs_handle, rid, request);
311	}	312	}
312		313
313	void tmpfs_read(ipc_callid_t rid, ipc_call_t *request)	314	void tmpfs_read(ipc_callid_t rid, ipc_call_t *request)
314	{	315	{
315	int dev_handle = IPC_GET_ARG1(*request);	316	int dev_handle = IPC_GET_ARG1(*request);
316	unsigned long index = IPC_GET_ARG2(*request);	317	unsigned long index = IPC_GET_ARG2(*request);
317	off_t pos = IPC_GET_ARG3(*request);	318	off_t pos = IPC_GET_ARG3(*request);
318		319
319	/*	320	/*
320	* Lookup the respective dentry.	321	* Lookup the respective dentry.
321	*/	322	*/
322	link_t *hlp;	323	link_t *hlp;
323	hlp = hash_table_find(&dentries, &index);	324	hlp = hash_table_find(&dentries, &index);
324	if (!hlp) {	325	if (!hlp) {
325	ipc_answer_0(rid, ENOENT);	326	ipc_answer_0(rid, ENOENT);
326	return;	327	return;
327	}	328	}
328	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,	329	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
329	dh_link);	330	dh_link);
330		331
331	/*	332	/*
332	* Receive the read request.	333	* Receive the read request.
333	*/	334	*/
334	ipc_callid_t callid;	335	ipc_callid_t callid;
335	size_t len;	336	size_t len;
336	if (!ipc_data_read_receive(&callid, &len)) {	337	if (!ipc_data_read_receive(&callid, &len)) {
337	ipc_answer_0(callid, EINVAL);	338	ipc_answer_0(callid, EINVAL);
338	ipc_answer_0(rid, EINVAL);	339	ipc_answer_0(rid, EINVAL);
339	return;	340	return;
340	}	341	}
341		342
342	size_t bytes;	343	size_t bytes;
343	if (dentry->type == TMPFS_FILE) {	344	if (dentry->type == TMPFS_FILE) {
344	bytes = max(0, min(dentry->size - pos, len));	345	bytes = max(0, min(dentry->size - pos, len));
345	(void) ipc_data_read_finalize(callid, dentry->data + pos,	346	(void) ipc_data_read_finalize(callid, dentry->data + pos,
346	bytes);	347	bytes);
347	} else {	348	} else {
348	int i;	349	int i;
349	tmpfs_dentry_t *cur;	350	tmpfs_dentry_t *cur;
350		351
351	assert(dentry->type == TMPFS_DIRECTORY);	352	assert(dentry->type == TMPFS_DIRECTORY);
352		353
353	/*	354	/*
354	* Yes, we really use O(n) algorithm here.	355	* Yes, we really use O(n) algorithm here.
355	* If it bothers someone, it could be fixed by introducing a	356	* If it bothers someone, it could be fixed by introducing a
356	* hash table.	357	* hash table.
357	*/	358	*/
358	for (i = 0, cur = dentry->child; i < pos && cur; i++,	359	for (i = 0, cur = dentry->child; i < pos && cur; i++,
359	cur = cur->sibling)	360	cur = cur->sibling)
360	;	361	;
361		362
362	if (!cur) {	363	if (!cur) {
363	ipc_answer_0(callid, ENOENT);	364	ipc_answer_0(callid, ENOENT);
364	ipc_answer_1(rid, ENOENT, 0);	365	ipc_answer_1(rid, ENOENT, 0);
365	return;	366	return;
366	}	367	}
367		368
368	(void) ipc_data_read_finalize(callid, cur->name,	369	(void) ipc_data_read_finalize(callid, cur->name,
369	strlen(cur->name) + 1);	370	strlen(cur->name) + 1);
370	bytes = 1;	371	bytes = 1;
371	}	372	}
372		373
373	/*	374	/*
374	* Answer the VFS_READ call.	375	* Answer the VFS_READ call.
375	*/	376	*/
376	ipc_answer_1(rid, EOK, bytes);	377	ipc_answer_1(rid, EOK, bytes);
377	}	378	}
378		379
379	void tmpfs_write(ipc_callid_t rid, ipc_call_t *request)	380	void tmpfs_write(ipc_callid_t rid, ipc_call_t *request)
380	{	381	{
381	int dev_handle = IPC_GET_ARG1(*request);	382	int dev_handle = IPC_GET_ARG1(*request);
382	unsigned long index = IPC_GET_ARG2(*request);	383	unsigned long index = IPC_GET_ARG2(*request);
383	off_t pos = IPC_GET_ARG3(*request);	384	off_t pos = IPC_GET_ARG3(*request);
384		385
385	/*	386	/*
386	* Lookup the respective dentry.	387	* Lookup the respective dentry.
387	*/	388	*/
388	link_t *hlp;	389	link_t *hlp;
389	hlp = hash_table_find(&dentries, &index);	390	hlp = hash_table_find(&dentries, &index);
390	if (!hlp) {	391	if (!hlp) {
391	ipc_answer_0(rid, ENOENT);	392	ipc_answer_0(rid, ENOENT);
392	return;	393	return;
393	}	394	}
394	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,	395	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
395	dh_link);	396	dh_link);
396		397
397	/*	398	/*
398	* Receive the write request.	399	* Receive the write request.
399	*/	400	*/
400	ipc_callid_t callid;	401	ipc_callid_t callid;
401	size_t len;	402	size_t len;
402	if (!ipc_data_write_receive(&callid, &len)) {	403	if (!ipc_data_write_receive(&callid, &len)) {
403	ipc_answer_0(callid, EINVAL);	404	ipc_answer_0(callid, EINVAL);
404	ipc_answer_0(rid, EINVAL);	405	ipc_answer_0(rid, EINVAL);
405	return;	406	return;
406	}	407	}
407		408
408	/*	409	/*
409	* Check whether the file needs to grow.	410	* Check whether the file needs to grow.
410	*/	411	*/
411	if (pos + len <= dentry->size) {	412	if (pos + len <= dentry->size) {
412	/* The file size is not changing. */	413	/* The file size is not changing. */
413	(void) ipc_data_write_finalize(callid, dentry->data + pos, len);	414	(void) ipc_data_write_finalize(callid, dentry->data + pos, len);
414	ipc_answer_2(rid, EOK, len, dentry->size);	415	ipc_answer_2(rid, EOK, len, dentry->size);
415	return;	416	return;
416	}	417	}
417	size_t delta = (pos + len) - dentry->size;	418	size_t delta = (pos + len) - dentry->size;
418	/*	419	/*
419	* At this point, we are deliberately extremely straightforward and	420	* At this point, we are deliberately extremely straightforward and
420	* simply realloc the contents of the file on every write that grows the	421	* simply realloc the contents of the file on every write that grows the
421	* file. In the end, the situation might not be as bad as it may look:	422	* file. In the end, the situation might not be as bad as it may look:
422	* our heap allocator can save us and just grow the block whenever	423	* our heap allocator can save us and just grow the block whenever
423	* possible.	424	* possible.
424	*/	425	*/
425	void *newdata = realloc(dentry->data, dentry->size + delta);	426	void *newdata = realloc(dentry->data, dentry->size + delta);
426	if (!newdata) {	427	if (!newdata) {
427	ipc_answer_0(callid, ENOMEM);	428	ipc_answer_0(callid, ENOMEM);
428	ipc_answer_2(rid, EOK, 0, dentry->size);	429	ipc_answer_2(rid, EOK, 0, dentry->size);
429	return;	430	return;
430	}	431	}
431	/* Clear any newly allocated memory in order to emulate gaps. */	432	/* Clear any newly allocated memory in order to emulate gaps. */
432	memset(newdata + dentry->size, 0, delta);	433	memset(newdata + dentry->size, 0, delta);
433	dentry->size += delta;	434	dentry->size += delta;
434	dentry->data = newdata;	435	dentry->data = newdata;
435	(void) ipc_data_write_finalize(callid, dentry->data + pos, len);	436	(void) ipc_data_write_finalize(callid, dentry->data + pos, len);
436	ipc_answer_2(rid, EOK, len, dentry->size);	437	ipc_answer_2(rid, EOK, len, dentry->size);
437	}	438	}
438		439
439	void tmpfs_truncate(ipc_callid_t rid, ipc_call_t *request)	440	void tmpfs_truncate(ipc_callid_t rid, ipc_call_t *request)
440	{	441	{
441	int dev_handle = IPC_GET_ARG1(*request);	442	int dev_handle = IPC_GET_ARG1(*request);
442	unsigned long index = IPC_GET_ARG2(*request);	443	unsigned long index = IPC_GET_ARG2(*request);
443	size_t size = IPC_GET_ARG3(*request);	444	size_t size = IPC_GET_ARG3(*request);
444		445
445	/*	446	/*
446	* Lookup the respective dentry.	447	* Lookup the respective dentry.
447	*/	448	*/
448	link_t *hlp;	449	link_t *hlp;
449	hlp = hash_table_find(&dentries, &index);	450	hlp = hash_table_find(&dentries, &index);
450	if (!hlp) {	451	if (!hlp) {
451	ipc_answer_0(rid, ENOENT);	452	ipc_answer_0(rid, ENOENT);
452	return;	453	return;
453	}	454	}
454	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,	455	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
455	dh_link);	456	dh_link);
456		457
457	if (size == dentry->size) {	458	if (size == dentry->size) {
458	ipc_answer_0(rid, EOK);	459	ipc_answer_0(rid, EOK);
459	return;	460	return;
460	}	461	}
461		462
462	void *newdata = realloc(dentry->data, size);	463	void *newdata = realloc(dentry->data, size);
463	if (!newdata) {	464	if (!newdata) {
464	ipc_answer_0(rid, ENOMEM);	465	ipc_answer_0(rid, ENOMEM);
465	return;	466	return;
466	}	467	}
467	if (size > dentry->size) {	468	if (size > dentry->size) {
468	size_t delta = size - dentry->size;	469	size_t delta = size - dentry->size;
469	memset(newdata + dentry->size, 0, delta);	470	memset(newdata + dentry->size, 0, delta);
470	}	471	}
471	dentry->size = size;	472	dentry->size = size;
472	dentry->data = newdata;	473	dentry->data = newdata;
473	ipc_answer_0(rid, EOK);	474	ipc_answer_0(rid, EOK);
474	}	475	}
475		476
476	void tmpfs_destroy(ipc_callid_t rid, ipc_call_t *request)	477	void tmpfs_destroy(ipc_callid_t rid, ipc_call_t *request)
477	{	478	{
478	int dev_handle = IPC_GET_ARG1(*request);	479	int dev_handle = IPC_GET_ARG1(*request);
479	unsigned long index = IPC_GET_ARG2(*request);	480	unsigned long index = IPC_GET_ARG2(*request);
480		481
481	link_t *hlp;	482	link_t *hlp;
482	hlp = hash_table_find(&dentries, &index);	483	hlp = hash_table_find(&dentries, &index);
483	if (!hlp) {	484	if (!hlp) {
484	ipc_answer_0(rid, ENOENT);	485	ipc_answer_0(rid, ENOENT);
485	return;	486	return;
486	}	487	}
487	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,	488	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
488	dh_link);	489	dh_link);
489	tmpfs_destroy_node(dentry);	490	tmpfs_destroy_node(dentry);
490	ipc_answer_0(rid, EOK);	491	ipc_answer_0(rid, EOK);
491	}	492	}
492		493
493	/**	494	/**
494	* @}	495	* @}
495	*/	496	*/
496		497

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(root)/trunk/uspace/srv/fs/tmpfs/tmpfs_ops.c – Rev 2756 → 2757