WebSVN – HelenOS – Diff – /branches/network/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 <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
 
#define TMPFS_GET_INDEX(x)  (((tmpfs_dentry_t *)(x))->index)
#define TMPFS_GET_LNKCNT(x) 1
 
/*
 * 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 nodep     Node to compare the path component with.
 * @param component Array of characters holding component name.
 *
 * @return      True on match, false otherwise.
 */
static bool match_component(void *nodep, const char *component)
{
    tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) nodep;
 
    return !strcmp(dentry->name, component);
}
 
static void *create_node(void *nodep,
    const char *component, int lflag)
{
    tmpfs_dentry_t *dentry = (tmpfs_dentry_t *) nodep;
 
    assert(dentry->type == TMPFS_DIRECTORY);
    assert((lflag & L_FILE) ^ (lflag & L_DIRECTORY));
 
    tmpfs_dentry_t *node = malloc(sizeof(tmpfs_dentry_t));
    if (!node)
        return NULL;
    size_t len = strlen(component);
    char *name = malloc(len + 1);
    if (!name) {
        free(node);
        return NULL;
    }
    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 (void *) node;
}
 
static int destroy_component(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;
 
    return EOK;
}
 
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;
                }
                void *nodep = create_node(dcur,
                    component, lflag);
                if (nodep) {
                    ipc_answer_5(rid, EOK,
                        tmpfs_reg.fs_handle, dev_handle,
                        TMPFS_GET_INDEX(nodep), 0,
                        TMPFS_GET_LNKCNT(nodep));
                } 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;
               
            void *nodep = create_node(dcur, component, lflag);
            if (nodep) {
                ipc_answer_5(rid, EOK, tmpfs_reg.fs_handle,
                    dev_handle, TMPFS_GET_INDEX(nodep), 0,
                    TMPFS_GET_LNKCNT(nodep));
            } else {
                ipc_answer_0(rid, ENOSPC);
            }
            return;
        }
        ipc_answer_0(rid, ENOENT);
        return;
    }
 
    /* handle hit */
    if (lflag & L_DESTROY) {
        unsigned old_lnkcnt = TMPFS_GET_LNKCNT(dcur);
        int res = destroy_component(dcur);
        ipc_answer_5(rid, (ipcarg_t)res, tmpfs_reg.fs_handle,
            dev_handle, dcur->index, dcur->size, old_lnkcnt);
        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_5(rid, EOK, tmpfs_reg.fs_handle, dev_handle, dcur->index,
        dcur->size, TMPFS_GET_LNKCNT(dcur));
}
 
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_free(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);
   
    assert(!dentry->parent);
    assert(!dentry->child);
    assert(!dentry->sibling);
 
    hash_table_remove(&dentries, &index, 1);
 
    if (dentry->type == TMPFS_FILE)
        free(dentry->data);
    free(dentry->name);
    free(dentry);
 
    ipc_answer_0(rid, EOK);
}
 
/**
 * @}
 */
 

Rev 2736	Rev 2739
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 <dirent.h>	48	#include <dirent.h>
49	#include <assert.h>	49	#include <assert.h>
50	#include <sys/types.h>	50	#include <sys/types.h>
51	#include <libadt/hash_table.h>	51	#include <libadt/hash_table.h>
52	#include <as.h>	52	#include <as.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 PLB_GET_CHAR(i) (tmpfs_reg.plb_ro[(i) % PLB_SIZE])	57	#define PLB_GET_CHAR(i) (tmpfs_reg.plb_ro[(i) % PLB_SIZE])
58		58
59	#define DENTRIES_BUCKETS 256	59	#define DENTRIES_BUCKETS 256
60		60
61	#define TMPFS_GET_INDEX(x) (((tmpfs_dentry_t *)(x))->index)	61	#define TMPFS_GET_INDEX(x) (((tmpfs_dentry_t *)(x))->index)
62	#define TMPFS_GET_LNKCNT(x) 1	62	#define TMPFS_GET_LNKCNT(x) 1
63		63
64	/*	64	/*
65	* Hash table of all directory entries.	65	* Hash table of all directory entries.
66	*/	66	*/
67	hash_table_t dentries;	67	hash_table_t dentries;
68		68
69	static hash_index_t dentries_hash(unsigned long *key)	69	static hash_index_t dentries_hash(unsigned long *key)
70	{	70	{
71	return *key % DENTRIES_BUCKETS;	71	return *key % DENTRIES_BUCKETS;
72	}	72	}
73		73
74	static int dentries_compare(unsigned long *key, hash_count_t keys,	74	static int dentries_compare(unsigned long *key, hash_count_t keys,
75	link_t *item)	75	link_t *item)
76	{	76	{
77	tmpfs_dentry_t *dentry = hash_table_get_instance(item, tmpfs_dentry_t,	77	tmpfs_dentry_t *dentry = hash_table_get_instance(item, tmpfs_dentry_t,
78	dh_link);	78	dh_link);
79	return dentry->index == *key;	79	return dentry->index == *key;
80	}	80	}
81		81
82	static void dentries_remove_callback(link_t *item)	82	static void dentries_remove_callback(link_t *item)
83	{	83	{
84	}	84	}
85		85
86	/** TMPFS dentries hash table operations. */	86	/** TMPFS dentries hash table operations. */
87	hash_table_operations_t dentries_ops = {	87	hash_table_operations_t dentries_ops = {
88	.hash = dentries_hash,	88	.hash = dentries_hash,
89	.compare = dentries_compare,	89	.compare = dentries_compare,
90	.remove_callback = dentries_remove_callback	90	.remove_callback = dentries_remove_callback
91	};	91	};
92		92
93	unsigned tmpfs_next_index = 1;	93	unsigned tmpfs_next_index = 1;
94		94
95	static void tmpfs_dentry_initialize(tmpfs_dentry_t *dentry)	95	static void tmpfs_dentry_initialize(tmpfs_dentry_t *dentry)
96	{	96	{
97	dentry->index = 0;	97	dentry->index = 0;
98	dentry->parent = NULL;	98	dentry->parent = NULL;
99	dentry->sibling = NULL;	99	dentry->sibling = NULL;
100	dentry->child = NULL;	100	dentry->child = NULL;
101	dentry->name = NULL;	101	dentry->name = NULL;
102	dentry->type = TMPFS_NONE;	102	dentry->type = TMPFS_NONE;
103	dentry->size = 0;	103	dentry->size = 0;
104	dentry->data = NULL;	104	dentry->data = NULL;
105	link_initialize(&dentry->dh_link);	105	link_initialize(&dentry->dh_link);
106	}	106	}
107		107
108	/*	108	/*
109	* For now, we don't distinguish between different dev_handles/instances. All	109	* For now, we don't distinguish between different dev_handles/instances. All
110	* requests resolve to the only instance, rooted in the following variable.	110	* requests resolve to the only instance, rooted in the following variable.
111	*/	111	*/
112	static tmpfs_dentry_t *root;	112	static tmpfs_dentry_t *root;
113		113
114	static bool tmpfs_init(void)	114	static bool tmpfs_init(void)
115	{	115	{
116	if (!hash_table_create(&dentries, DENTRIES_BUCKETS, 1, &dentries_ops))	116	if (!hash_table_create(&dentries, DENTRIES_BUCKETS, 1, &dentries_ops))
117	return false;	117	return false;
118		118
119	root = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));	119	root = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
120	if (!root)	120	if (!root)
121	return false;	121	return false;
122	tmpfs_dentry_initialize(root);	122	tmpfs_dentry_initialize(root);
123	root->index = tmpfs_next_index++;	123	root->index = tmpfs_next_index++;
124	root->name = "";	124	root->name = "";
125	root->type = TMPFS_DIRECTORY;	125	root->type = TMPFS_DIRECTORY;
126	hash_table_insert(&dentries, &root->index, &root->dh_link);	126	hash_table_insert(&dentries, &root->index, &root->dh_link);
127		127
128	return true;	128	return true;
129	}	129	}
130		130
131	/** Compare one component of path to a directory entry.	131	/** Compare one component of path to a directory entry.
132	*	132	*
133	* @param nodep Node to compare the path component with.	133	* @param nodep Node to compare the path component with.
134	* @param component Array of characters holding component name.	134	* @param component Array of characters holding component name.
135	*	135	*
136	* @return True on match, false otherwise.	136	* @return True on match, false otherwise.
137	*/	137	*/
138	static bool match_component(void nodep, const char component)	138	static bool match_component(void nodep, const char component)
139	{	139	{
140	tmpfs_dentry_t dentry = (tmpfs_dentry_t ) nodep;	140	tmpfs_dentry_t dentry = (tmpfs_dentry_t ) nodep;
141		141
142	return !strcmp(dentry->name, component);	142	return !strcmp(dentry->name, component);
143	}	143	}
144		144
145	static void create_node(void nodep,	145	static void create_node(void nodep,
146	const char *component, int lflag)	146	const char *component, int lflag)
147	{	147	{
148	tmpfs_dentry_t dentry = (tmpfs_dentry_t ) nodep;	148	tmpfs_dentry_t dentry = (tmpfs_dentry_t ) nodep;
149		149
150	assert(dentry->type == TMPFS_DIRECTORY);	150	assert(dentry->type == TMPFS_DIRECTORY);
151	assert((lflag & L_FILE) ^ (lflag & L_DIRECTORY));	151	assert((lflag & L_FILE) ^ (lflag & L_DIRECTORY));
152		152
153	tmpfs_dentry_t *node = malloc(sizeof(tmpfs_dentry_t));	153	tmpfs_dentry_t *node = malloc(sizeof(tmpfs_dentry_t));
154	if (!node)	154	if (!node)
155	return NULL;	155	return NULL;
156	size_t len = strlen(component);	156	size_t len = strlen(component);
157	char *name = malloc(len + 1);	157	char *name = malloc(len + 1);
158	if (!name) {	158	if (!name) {
159	free(node);	159	free(node);
160	return NULL;	160	return NULL;
161	}	161	}
162	strcpy(name, component);	162	strcpy(name, component);
163		163
164	tmpfs_dentry_initialize(node);	164	tmpfs_dentry_initialize(node);
165	node->index = tmpfs_next_index++;	165	node->index = tmpfs_next_index++;
166	node->name = name;	166	node->name = name;
167	node->parent = dentry;	167	node->parent = dentry;
168	if (lflag & L_DIRECTORY)	168	if (lflag & L_DIRECTORY)
169	node->type = TMPFS_DIRECTORY;	169	node->type = TMPFS_DIRECTORY;
170	else	170	else
171	node->type = TMPFS_FILE;	171	node->type = TMPFS_FILE;
172		172
173	/* Insert the new node into the namespace. */	173	/* Insert the new node into the namespace. */
174	if (dentry->child) {	174	if (dentry->child) {
175	tmpfs_dentry_t *tmp = dentry->child;	175	tmpfs_dentry_t *tmp = dentry->child;
176	while (tmp->sibling)	176	while (tmp->sibling)
177	tmp = tmp->sibling;	177	tmp = tmp->sibling;
178	tmp->sibling = node;	178	tmp->sibling = node;
179	} else {	179	} else {
180	dentry->child = node;	180	dentry->child = node;
181	}	181	}
182		182
183	/* Insert the new node into the dentry hash table. */	183	/* Insert the new node into the dentry hash table. */
184	hash_table_insert(&dentries, &node->index, &node->dh_link);	184	hash_table_insert(&dentries, &node->index, &node->dh_link);
185	return (void *) node;	185	return (void *) node;
186	}	186	}
187		187
188	static int destroy_component(void *nodeptr)	188	static int destroy_component(void *nodeptr)
189	{	189	{
190	tmpfs_dentry_t dentry = (tmpfs_dentry_t )nodeptr;	190	tmpfs_dentry_t dentry = (tmpfs_dentry_t )nodeptr;
191		191
192	if (dentry->child)	192	if (dentry->child)
193	return ENOTEMPTY;	193	return ENOTEMPTY;
194		194
195	if (!dentry->parent)	195	if (!dentry->parent)
196	return EBUSY;	196	return EBUSY;
197		197
198	if (dentry->parent->child == dentry) {	198	if (dentry->parent->child == dentry) {
199	dentry->parent->child = dentry->sibling;	199	dentry->parent->child = dentry->sibling;
200	} else {	200	} else {
201	/* TODO: consider doubly linked list for organizing siblings. */	201	/* TODO: consider doubly linked list for organizing siblings. */
202	tmpfs_dentry_t *tmp = dentry->parent->child;	202	tmpfs_dentry_t *tmp = dentry->parent->child;
203	while (tmp->sibling != dentry)	203	while (tmp->sibling != dentry)
204	tmp = tmp->sibling;	204	tmp = tmp->sibling;
205	tmp->sibling = dentry->sibling;	205	tmp->sibling = dentry->sibling;
206	}	206	}
207	dentry->sibling = NULL;	207	dentry->sibling = NULL;
208	dentry->parent = NULL;	208	dentry->parent = NULL;
209		209
210	return EOK;	210	return EOK;
211	}	211	}
212		212
213	void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request)	213	void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request)
214	{	214	{
215	unsigned next = IPC_GET_ARG1(*request);	215	unsigned next = IPC_GET_ARG1(*request);
216	unsigned last = IPC_GET_ARG2(*request);	216	unsigned last = IPC_GET_ARG2(*request);
217	int dev_handle = IPC_GET_ARG3(*request);	217	int dev_handle = IPC_GET_ARG3(*request);
218	int lflag = IPC_GET_ARG4(*request);	218	int lflag = IPC_GET_ARG4(*request);
219		219
220	if (last < next)	220	if (last < next)
221	last += PLB_SIZE;	221	last += PLB_SIZE;
222		222
223	/*	223	/*
224	* Initialize TMPFS.	224	* Initialize TMPFS.
225	*/	225	*/
226	if (!root && !tmpfs_init()) {	226	if (!root && !tmpfs_init()) {
227	ipc_answer_0(rid, ENOMEM);	227	ipc_answer_0(rid, ENOMEM);
228	return;	228	return;
229	}	229	}
230		230
231	tmpfs_dentry_t *dtmp = root->child;	231	tmpfs_dentry_t *dtmp = root->child;
232	tmpfs_dentry_t *dcur = root;	232	tmpfs_dentry_t *dcur = root;
233		233
234	if (PLB_GET_CHAR(next) == '/')	234	if (PLB_GET_CHAR(next) == '/')
235	next++; /* eat slash */	235	next++; /* eat slash */
236		236
237	char component[NAME_MAX + 1];	237	char component[NAME_MAX + 1];
238	int len = 0;	238	int len = 0;
239	while (dtmp && next <= last) {	239	while (dtmp && next <= last) {
240		240
241	/* collect the component */	241	/* collect the component */
242	if (PLB_GET_CHAR(next) != '/') {	242	if (PLB_GET_CHAR(next) != '/') {
243	if (len + 1 == NAME_MAX) {	243	if (len + 1 == NAME_MAX) {
244	/* comopnent length overflow */	244	/* comopnent length overflow */
245	ipc_answer_0(rid, ENAMETOOLONG);	245	ipc_answer_0(rid, ENAMETOOLONG);
246	return;	246	return;
247	}	247	}
248	component[len++] = PLB_GET_CHAR(next);	248	component[len++] = PLB_GET_CHAR(next);
249	next++; /* process next character */	249	next++; /* process next character */
250	if (next <= last)	250	if (next <= last)
251	continue;	251	continue;
252	}	252	}
253		253
254	assert(len);	254	assert(len);
255	component[len] = '\0';	255	component[len] = '\0';
256	next++; /* eat slash */	256	next++; /* eat slash */
257	len = 0;	257	len = 0;
258		258
259	/* match the component */	259	/* match the component */
260	while (dtmp && !match_component(dtmp, component))	260	while (dtmp && !match_component(dtmp, component))
261	dtmp = dtmp->sibling;	261	dtmp = dtmp->sibling;
262		262
263	/* handle miss: match amongst siblings */	263	/* handle miss: match amongst siblings */
264	if (!dtmp) {	264	if (!dtmp) {
265	if ((next > last) && (lflag & L_CREATE)) {	265	if ((next > last) && (lflag & L_CREATE)) {
266	/* no components left and L_CREATE specified */	266	/* no components left and L_CREATE specified */
267	if (dcur->type != TMPFS_DIRECTORY) {	267	if (dcur->type != TMPFS_DIRECTORY) {
268	ipc_answer_0(rid, ENOTDIR);	268	ipc_answer_0(rid, ENOTDIR);
269	return;	269	return;
270	}	270	}
271	void *nodep = create_node(dcur,	271	void *nodep = create_node(dcur,
272	component, lflag);	272	component, lflag);
273	if (nodep) {	273	if (nodep) {
274	ipc_answer_5(rid, EOK,	274	ipc_answer_5(rid, EOK,
275	tmpfs_reg.fs_handle, dev_handle,	275	tmpfs_reg.fs_handle, dev_handle,
276	TMPFS_GET_INDEX(nodep), 0,	276	TMPFS_GET_INDEX(nodep), 0,
277	TMPFS_GET_LNKCNT(nodep));	277	TMPFS_GET_LNKCNT(nodep));
278	} else {	278	} else {
279	ipc_answer_0(rid, ENOSPC);	279	ipc_answer_0(rid, ENOSPC);
280	}	280	}
281	return;	281	return;
282	}	282	}
283	ipc_answer_0(rid, ENOENT);	283	ipc_answer_0(rid, ENOENT);
284	return;	284	return;
285	}	285	}
286		286
287	/* descend one level */	287	/* descend one level */
288	dcur = dtmp;	288	dcur = dtmp;
289	dtmp = dtmp->child;	289	dtmp = dtmp->child;
290	}	290	}
291		291
292	/* handle miss: excessive components */	292	/* handle miss: excessive components */
293	if (!dtmp && next <= last) {	293	if (!dtmp && next <= last) {
294	if (lflag & L_CREATE) {	294	if (lflag & L_CREATE) {
295	if (dcur->type != TMPFS_DIRECTORY) {	295	if (dcur->type != TMPFS_DIRECTORY) {
296	ipc_answer_0(rid, ENOTDIR);	296	ipc_answer_0(rid, ENOTDIR);
297	return;	297	return;
298	}	298	}
299		299
300	/* collect next component */	300	/* collect next component */
301	while (next <= last) {	301	while (next <= last) {
302	if (PLB_GET_CHAR(next) == '/') {	302	if (PLB_GET_CHAR(next) == '/') {
303	/* more than one component */	303	/* more than one component */
304	ipc_answer_0(rid, ENOENT);	304	ipc_answer_0(rid, ENOENT);
305	return;	305	return;
306	}	306	}
307	if (len + 1 == NAME_MAX) {	307	if (len + 1 == NAME_MAX) {
308	/* component length overflow */	308	/* component length overflow */
309	ipc_answer_0(rid, ENAMETOOLONG);	309	ipc_answer_0(rid, ENAMETOOLONG);
310	return;	310	return;
311	}	311	}
312	component[len++] = PLB_GET_CHAR(next);	312	component[len++] = PLB_GET_CHAR(next);
313	next++; /* process next character */	313	next++; /* process next character */
314	}	314	}
315	assert(len);	315	assert(len);
316	component[len] = '\0';	316	component[len] = '\0';
317	len = 0;	317	len = 0;
318		318
319	void *nodep = create_node(dcur, component, lflag);	319	void *nodep = create_node(dcur, component, lflag);
320	if (nodep) {	320	if (nodep) {
321	ipc_answer_5(rid, EOK, tmpfs_reg.fs_handle,	321	ipc_answer_5(rid, EOK, tmpfs_reg.fs_handle,
322	dev_handle, TMPFS_GET_INDEX(nodep), 0,	322	dev_handle, TMPFS_GET_INDEX(nodep), 0,
323	TMPFS_GET_LNKCNT(nodep));	323	TMPFS_GET_LNKCNT(nodep));
324	} else {	324	} else {
325	ipc_answer_0(rid, ENOSPC);	325	ipc_answer_0(rid, ENOSPC);
326	}	326	}
327	return;	327	return;
328	}	328	}
329	ipc_answer_0(rid, ENOENT);	329	ipc_answer_0(rid, ENOENT);
330	return;	330	return;
331	}	331	}
332		332
333	/* handle hit */	333	/* handle hit */
334	if (lflag & L_DESTROY) {	334	if (lflag & L_DESTROY) {
335	unsigned old_lnkcnt = TMPFS_GET_LNKCNT(dcur);	335	unsigned old_lnkcnt = TMPFS_GET_LNKCNT(dcur);
336	int res = destroy_component(dcur);	336	int res = destroy_component(dcur);
337	ipc_answer_5(rid, (ipcarg_t)res, tmpfs_reg.fs_handle,	337	ipc_answer_5(rid, (ipcarg_t)res, tmpfs_reg.fs_handle,
338	dev_handle, dcur->index, dcur->size, old_lnkcnt);	338	dev_handle, dcur->index, dcur->size, old_lnkcnt);
339	return;	339	return;
340	}	340	}
341	if ((lflag & (L_CREATE \| L_EXCLUSIVE)) == (L_CREATE \| L_EXCLUSIVE)) {	341	if ((lflag & (L_CREATE \| L_EXCLUSIVE)) == (L_CREATE \| L_EXCLUSIVE)) {
342	ipc_answer_0(rid, EEXIST);	342	ipc_answer_0(rid, EEXIST);
343	return;	343	return;
344	}	344	}
345	if ((lflag & L_FILE) && (dcur->type != TMPFS_FILE)) {	345	if ((lflag & L_FILE) && (dcur->type != TMPFS_FILE)) {
346	ipc_answer_0(rid, EISDIR);	346	ipc_answer_0(rid, EISDIR);
347	return;	347	return;
348	}	348	}
349	if ((lflag & L_DIRECTORY) && (dcur->type != TMPFS_DIRECTORY)) {	349	if ((lflag & L_DIRECTORY) && (dcur->type != TMPFS_DIRECTORY)) {
350	ipc_answer_0(rid, ENOTDIR);	350	ipc_answer_0(rid, ENOTDIR);
351	return;	351	return;
352	}	352	}
353		353
354	ipc_answer_5(rid, EOK, tmpfs_reg.fs_handle, dev_handle, dcur->index,	354	ipc_answer_5(rid, EOK, tmpfs_reg.fs_handle, dev_handle, dcur->index,
355	dcur->size, TMPFS_GET_LNKCNT(dcur));	355	dcur->size, TMPFS_GET_LNKCNT(dcur));
356	}	356	}
357		357
358	void tmpfs_read(ipc_callid_t rid, ipc_call_t *request)	358	void tmpfs_read(ipc_callid_t rid, ipc_call_t *request)
359	{	359	{
360	int dev_handle = IPC_GET_ARG1(*request);	360	int dev_handle = IPC_GET_ARG1(*request);
361	unsigned long index = IPC_GET_ARG2(*request);	361	unsigned long index = IPC_GET_ARG2(*request);
362	off_t pos = IPC_GET_ARG3(*request);	362	off_t pos = IPC_GET_ARG3(*request);
363		363
364	/*	364	/*
365	* Lookup the respective dentry.	365	* Lookup the respective dentry.
366	*/	366	*/
367	link_t *hlp;	367	link_t *hlp;
368	hlp = hash_table_find(&dentries, &index);	368	hlp = hash_table_find(&dentries, &index);
369	if (!hlp) {	369	if (!hlp) {
370	ipc_answer_0(rid, ENOENT);	370	ipc_answer_0(rid, ENOENT);
371	return;	371	return;
372	}	372	}
373	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,	373	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
374	dh_link);	374	dh_link);
375		375
376	/*	376	/*
377	* Receive the read request.	377	* Receive the read request.
378	*/	378	*/
379	ipc_callid_t callid;	379	ipc_callid_t callid;
380	size_t len;	380	size_t len;
381	if (!ipc_data_read_receive(&callid, &len)) {	381	if (!ipc_data_read_receive(&callid, &len)) {
382	ipc_answer_0(callid, EINVAL);	382	ipc_answer_0(callid, EINVAL);
383	ipc_answer_0(rid, EINVAL);	383	ipc_answer_0(rid, EINVAL);
384	return;	384	return;
385	}	385	}
386		386
387	size_t bytes;	387	size_t bytes;
388	if (dentry->type == TMPFS_FILE) {	388	if (dentry->type == TMPFS_FILE) {
389	bytes = max(0, min(dentry->size - pos, len));	389	bytes = max(0, min(dentry->size - pos, len));
390	(void) ipc_data_read_finalize(callid, dentry->data + pos,	390	(void) ipc_data_read_finalize(callid, dentry->data + pos,
391	bytes);	391	bytes);
392	} else {	392	} else {
393	int i;	393	int i;
394	tmpfs_dentry_t *cur = dentry->child;	394	tmpfs_dentry_t *cur;
395		395
396	assert(dentry->type == TMPFS_DIRECTORY);	396	assert(dentry->type == TMPFS_DIRECTORY);
397		397
398	/*	398	/*
399	* Yes, we really use O(n) algorithm here.	399	* Yes, we really use O(n) algorithm here.
400	* If it bothers someone, it could be fixed by introducing a	400	* If it bothers someone, it could be fixed by introducing a
401	* hash table.	401	* hash table.
402	*/	402	*/
403	for (i = 0, cur = dentry->child; i < pos && cur; i++,	403	for (i = 0, cur = dentry->child; i < pos && cur; i++,
404	cur = cur->sibling)	404	cur = cur->sibling)
405	;	405	;
406		406
407	if (!cur) {	407	if (!cur) {
408	ipc_answer_0(callid, ENOENT);	408	ipc_answer_0(callid, ENOENT);
409	ipc_answer_1(rid, ENOENT, 0);	409	ipc_answer_1(rid, ENOENT, 0);
410	return;	410	return;
411	}	411	}
412		412
413	(void) ipc_data_read_finalize(callid, cur->name,	413	(void) ipc_data_read_finalize(callid, cur->name,
414	strlen(cur->name) + 1);	414	strlen(cur->name) + 1);
415	bytes = 1;	415	bytes = 1;
416	}	416	}
417		417
418	/*	418	/*
419	* Answer the VFS_READ call.	419	* Answer the VFS_READ call.
420	*/	420	*/
421	ipc_answer_1(rid, EOK, bytes);	421	ipc_answer_1(rid, EOK, bytes);
422	}	422	}
423		423
424	void tmpfs_write(ipc_callid_t rid, ipc_call_t *request)	424	void tmpfs_write(ipc_callid_t rid, ipc_call_t *request)
425	{	425	{
426	int dev_handle = IPC_GET_ARG1(*request);	426	int dev_handle = IPC_GET_ARG1(*request);
427	unsigned long index = IPC_GET_ARG2(*request);	427	unsigned long index = IPC_GET_ARG2(*request);
428	off_t pos = IPC_GET_ARG3(*request);	428	off_t pos = IPC_GET_ARG3(*request);
429		429
430	/*	430	/*
431	* Lookup the respective dentry.	431	* Lookup the respective dentry.
432	*/	432	*/
433	link_t *hlp;	433	link_t *hlp;
434	hlp = hash_table_find(&dentries, &index);	434	hlp = hash_table_find(&dentries, &index);
435	if (!hlp) {	435	if (!hlp) {
436	ipc_answer_0(rid, ENOENT);	436	ipc_answer_0(rid, ENOENT);
437	return;	437	return;
438	}	438	}
439	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,	439	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
440	dh_link);	440	dh_link);
441		441
442	/*	442	/*
443	* Receive the write request.	443	* Receive the write request.
444	*/	444	*/
445	ipc_callid_t callid;	445	ipc_callid_t callid;
446	size_t len;	446	size_t len;
447	if (!ipc_data_write_receive(&callid, &len)) {	447	if (!ipc_data_write_receive(&callid, &len)) {
448	ipc_answer_0(callid, EINVAL);	448	ipc_answer_0(callid, EINVAL);
449	ipc_answer_0(rid, EINVAL);	449	ipc_answer_0(rid, EINVAL);
450	return;	450	return;
451	}	451	}
452		452
453	/*	453	/*
454	* Check whether the file needs to grow.	454	* Check whether the file needs to grow.
455	*/	455	*/
456	if (pos + len <= dentry->size) {	456	if (pos + len <= dentry->size) {
457	/* The file size is not changing. */	457	/* The file size is not changing. */
458	(void) ipc_data_write_finalize(callid, dentry->data + pos, len);	458	(void) ipc_data_write_finalize(callid, dentry->data + pos, len);
459	ipc_answer_2(rid, EOK, len, dentry->size);	459	ipc_answer_2(rid, EOK, len, dentry->size);
460	return;	460	return;
461	}	461	}
462	size_t delta = (pos + len) - dentry->size;	462	size_t delta = (pos + len) - dentry->size;
463	/*	463	/*
464	* At this point, we are deliberately extremely straightforward and	464	* At this point, we are deliberately extremely straightforward and
465	* simply realloc the contents of the file on every write that grows the	465	* simply realloc the contents of the file on every write that grows the
466	* file. In the end, the situation might not be as bad as it may look:	466	* file. In the end, the situation might not be as bad as it may look:
467	* our heap allocator can save us and just grow the block whenever	467	* our heap allocator can save us and just grow the block whenever
468	* possible.	468	* possible.
469	*/	469	*/
470	void *newdata = realloc(dentry->data, dentry->size + delta);	470	void *newdata = realloc(dentry->data, dentry->size + delta);
471	if (!newdata) {	471	if (!newdata) {
472	ipc_answer_0(callid, ENOMEM);	472	ipc_answer_0(callid, ENOMEM);
473	ipc_answer_2(rid, EOK, 0, dentry->size);	473	ipc_answer_2(rid, EOK, 0, dentry->size);
474	return;	474	return;
475	}	475	}
476	/* Clear any newly allocated memory in order to emulate gaps. */	476	/* Clear any newly allocated memory in order to emulate gaps. */
477	memset(newdata + dentry->size, 0, delta);	477	memset(newdata + dentry->size, 0, delta);
478	dentry->size += delta;	478	dentry->size += delta;
479	dentry->data = newdata;	479	dentry->data = newdata;
480	(void) ipc_data_write_finalize(callid, dentry->data + pos, len);	480	(void) ipc_data_write_finalize(callid, dentry->data + pos, len);
481	ipc_answer_2(rid, EOK, len, dentry->size);	481	ipc_answer_2(rid, EOK, len, dentry->size);
482	}	482	}
483		483
484	void tmpfs_truncate(ipc_callid_t rid, ipc_call_t *request)	484	void tmpfs_truncate(ipc_callid_t rid, ipc_call_t *request)
485	{	485	{
486	int dev_handle = IPC_GET_ARG1(*request);	486	int dev_handle = IPC_GET_ARG1(*request);
487	unsigned long index = IPC_GET_ARG2(*request);	487	unsigned long index = IPC_GET_ARG2(*request);
488	size_t size = IPC_GET_ARG3(*request);	488	size_t size = IPC_GET_ARG3(*request);
489		489
490	/*	490	/*
491	* Lookup the respective dentry.	491	* Lookup the respective dentry.
492	*/	492	*/
493	link_t *hlp;	493	link_t *hlp;
494	hlp = hash_table_find(&dentries, &index);	494	hlp = hash_table_find(&dentries, &index);
495	if (!hlp) {	495	if (!hlp) {
496	ipc_answer_0(rid, ENOENT);	496	ipc_answer_0(rid, ENOENT);
497	return;	497	return;
498	}	498	}
499	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,	499	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
500	dh_link);	500	dh_link);

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(root)/branches/network/uspace/srv/fs/tmpfs/tmpfs_ops.c @ 4717 – Rev 2736 → 2739