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 <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);
 
    /*
     * This is only for debugging. Once we can create files and directories
     * using VFS, we can get rid of this.
     */
    tmpfs_dentry_t *d;
    d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
    if (!d) {
        free(root);
        root = NULL;
        return false;
    }
    tmpfs_dentry_initialize(d);
    d->index = tmpfs_next_index++;
    root->child = d;
    d->parent = root;
    d->type = TMPFS_DIRECTORY;
    d->name = "dir1";
    hash_table_insert(&dentries, &d->index, &d->dh_link);
 
    d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
    if (!d) {
        free(root->child);
        free(root);
        root = NULL;
        return false;
    }
    tmpfs_dentry_initialize(d);
    d->index = tmpfs_next_index++;
    root->child->sibling = d;
    d->parent = root;
    d->type = TMPFS_DIRECTORY;
    d->name = "dir2";
    hash_table_insert(&dentries, &d->index, &d->dh_link);
   
    d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
    if (!d) {
        free(root->child->sibling);
        free(root->child);
        free(root);
        root = NULL;
        return false;
    }
    tmpfs_dentry_initialize(d);
    d->index = tmpfs_next_index++;
    root->child->child = d;
    d->parent = root->child;
    d->type = TMPFS_FILE;
    d->name = "file1";
    d->data = "This is the contents of /dir1/file1.\n";
    d->size = strlen(d->data);
    hash_table_insert(&dentries, &d->index, &d->dh_link);
 
    d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
    if (!d) {
        free(root->child->sibling);
        free(root->child->child);
        free(root->child);
        free(root);
        root = NULL;
        return false;
    }
    tmpfs_dentry_initialize(d);
    d->index = tmpfs_next_index++;
    root->child->sibling->child = d;
    d->parent = root->child->sibling;
    d->type = TMPFS_FILE;
    d->name = "file2";
    d->data = "This is the contents of /dir2/file2.\n";
    d->size = strlen(d->data);
    hash_table_insert(&dentries, &d->index, &d->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)
{
    return 0;
}
 
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) {
                    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;
        }
 
        /* descent 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_1(rid, EOK, len);
        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_1(rid, EOK, 0);
        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);
}
 
/**
 * @}
 */
 

Rev 2705	Rev 2706
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	/*	61	/*
62	* Hash table of all directory entries.	62	* Hash table of all directory entries.
63	*/	63	*/
64	hash_table_t dentries;	64	hash_table_t dentries;
65		65
66	static hash_index_t dentries_hash(unsigned long *key)	66	static hash_index_t dentries_hash(unsigned long *key)
67	{	67	{
68	return *key % DENTRIES_BUCKETS;	68	return *key % DENTRIES_BUCKETS;
69	}	69	}
70		70
71	static int dentries_compare(unsigned long *key, hash_count_t keys,	71	static int dentries_compare(unsigned long *key, hash_count_t keys,
72	link_t *item)	72	link_t *item)
73	{	73	{
74	tmpfs_dentry_t *dentry = hash_table_get_instance(item, tmpfs_dentry_t,	74	tmpfs_dentry_t *dentry = hash_table_get_instance(item, tmpfs_dentry_t,
75	dh_link);	75	dh_link);
76	return dentry->index == *key;	76	return dentry->index == *key;
77	}	77	}
78		78
79	static void dentries_remove_callback(link_t *item)	79	static void dentries_remove_callback(link_t *item)
80	{	80	{
81	}	81	}
82		82
83	/** TMPFS dentries hash table operations. */	83	/** TMPFS dentries hash table operations. */
84	hash_table_operations_t dentries_ops = {	84	hash_table_operations_t dentries_ops = {
85	.hash = dentries_hash,	85	.hash = dentries_hash,
86	.compare = dentries_compare,	86	.compare = dentries_compare,
87	.remove_callback = dentries_remove_callback	87	.remove_callback = dentries_remove_callback
88	};	88	};
89		89
90	unsigned tmpfs_next_index = 1;	90	unsigned tmpfs_next_index = 1;
91		91
92	static void tmpfs_dentry_initialize(tmpfs_dentry_t *dentry)	92	static void tmpfs_dentry_initialize(tmpfs_dentry_t *dentry)
93	{	93	{
94	dentry->index = 0;	94	dentry->index = 0;
95	dentry->parent = NULL;	95	dentry->parent = NULL;
96	dentry->sibling = NULL;	96	dentry->sibling = NULL;
97	dentry->child = NULL;	97	dentry->child = NULL;
98	dentry->name = NULL;	98	dentry->name = NULL;
99	dentry->type = TMPFS_NONE;	99	dentry->type = TMPFS_NONE;
100	dentry->size = 0;	100	dentry->size = 0;
101	dentry->data = NULL;	101	dentry->data = NULL;
102	link_initialize(&dentry->dh_link);	102	link_initialize(&dentry->dh_link);
103	}	103	}
104		104
105	/*	105	/*
106	* For now, we don't distinguish between different dev_handles/instances. All	106	* For now, we don't distinguish between different dev_handles/instances. All
107	* requests resolve to the only instance, rooted in the following variable.	107	* requests resolve to the only instance, rooted in the following variable.
108	*/	108	*/
109	static tmpfs_dentry_t *root;	109	static tmpfs_dentry_t *root;
110		110
111	static bool tmpfs_init(void)	111	static bool tmpfs_init(void)
112	{	112	{
113	if (!hash_table_create(&dentries, DENTRIES_BUCKETS, 1, &dentries_ops))	113	if (!hash_table_create(&dentries, DENTRIES_BUCKETS, 1, &dentries_ops))
114	return false;	114	return false;
115		115
116	root = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));	116	root = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
117	if (!root)	117	if (!root)
118	return false;	118	return false;
119	tmpfs_dentry_initialize(root);	119	tmpfs_dentry_initialize(root);
120	root->index = tmpfs_next_index++;	120	root->index = tmpfs_next_index++;
121	root->name = "";	121	root->name = "";
122	root->type = TMPFS_DIRECTORY;	122	root->type = TMPFS_DIRECTORY;
123	hash_table_insert(&dentries, &root->index, &root->dh_link);	123	hash_table_insert(&dentries, &root->index, &root->dh_link);
124		124
125	/*	125	/*
126	* This is only for debugging. Once we can create files and directories	126	* This is only for debugging. Once we can create files and directories
127	* using VFS, we can get rid of this.	127	* using VFS, we can get rid of this.
128	*/	128	*/
129	tmpfs_dentry_t *d;	129	tmpfs_dentry_t *d;
130	d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));	130	d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
131	if (!d) {	131	if (!d) {
132	free(root);	132	free(root);
133	root = NULL;	133	root = NULL;
134	return false;	134	return false;
135	}	135	}
136	tmpfs_dentry_initialize(d);	136	tmpfs_dentry_initialize(d);
137	d->index = tmpfs_next_index++;	137	d->index = tmpfs_next_index++;
138	root->child = d;	138	root->child = d;
139	d->parent = root;	139	d->parent = root;
140	d->type = TMPFS_DIRECTORY;	140	d->type = TMPFS_DIRECTORY;
141	d->name = "dir1";	141	d->name = "dir1";
142	hash_table_insert(&dentries, &d->index, &d->dh_link);	142	hash_table_insert(&dentries, &d->index, &d->dh_link);
143		143
144	d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));	144	d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
145	if (!d) {	145	if (!d) {
146	free(root->child);	146	free(root->child);
147	free(root);	147	free(root);
148	root = NULL;	148	root = NULL;
149	return false;	149	return false;
150	}	150	}
151	tmpfs_dentry_initialize(d);	151	tmpfs_dentry_initialize(d);
152	d->index = tmpfs_next_index++;	152	d->index = tmpfs_next_index++;
153	root->child->sibling = d;	153	root->child->sibling = d;
154	d->parent = root;	154	d->parent = root;
155	d->type = TMPFS_DIRECTORY;	155	d->type = TMPFS_DIRECTORY;
156	d->name = "dir2";	156	d->name = "dir2";
157	hash_table_insert(&dentries, &d->index, &d->dh_link);	157	hash_table_insert(&dentries, &d->index, &d->dh_link);
158		158
159	d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));	159	d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
160	if (!d) {	160	if (!d) {
161	free(root->child->sibling);	161	free(root->child->sibling);
162	free(root->child);	162	free(root->child);
163	free(root);	163	free(root);
164	root = NULL;	164	root = NULL;
165	return false;	165	return false;
166	}	166	}
167	tmpfs_dentry_initialize(d);	167	tmpfs_dentry_initialize(d);
168	d->index = tmpfs_next_index++;	168	d->index = tmpfs_next_index++;
169	root->child->child = d;	169	root->child->child = d;
170	d->parent = root->child;	170	d->parent = root->child;
171	d->type = TMPFS_FILE;	171	d->type = TMPFS_FILE;
172	d->name = "file1";	172	d->name = "file1";
173	d->data = "This is the contents of /dir1/file1.\n";	173	d->data = "This is the contents of /dir1/file1.\n";
174	d->size = strlen(d->data);	174	d->size = strlen(d->data);
175	hash_table_insert(&dentries, &d->index, &d->dh_link);	175	hash_table_insert(&dentries, &d->index, &d->dh_link);
176		176
177	d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));	177	d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
178	if (!d) {	178	if (!d) {
179	free(root->child->sibling);	179	free(root->child->sibling);
180	free(root->child->child);	180	free(root->child->child);
181	free(root->child);	181	free(root->child);
182	free(root);	182	free(root);
183	root = NULL;	183	root = NULL;
184	return false;	184	return false;
185	}	185	}
186	tmpfs_dentry_initialize(d);	186	tmpfs_dentry_initialize(d);
187	d->index = tmpfs_next_index++;	187	d->index = tmpfs_next_index++;
188	root->child->sibling->child = d;	188	root->child->sibling->child = d;
189	d->parent = root->child->sibling;	189	d->parent = root->child->sibling;
190	d->type = TMPFS_FILE;	190	d->type = TMPFS_FILE;
191	d->name = "file2";	191	d->name = "file2";
192	d->data = "This is the contents of /dir2/file2.\n";	192	d->data = "This is the contents of /dir2/file2.\n";
193	d->size = strlen(d->data);	193	d->size = strlen(d->data);
194	hash_table_insert(&dentries, &d->index, &d->dh_link);	194	hash_table_insert(&dentries, &d->index, &d->dh_link);
195		195
196	return true;	196	return true;
197	}	197	}
198		198
199	/** Compare one component of path to a directory entry.	199	/** Compare one component of path to a directory entry.
200	*	200	*
201	* @param dentry Directory entry to compare the path component with.	201	* @param dentry Directory entry to compare the path component with.
202	* @param component Array of characters holding component name.	202	* @param component Array of characters holding component name.
203	*	203	*
204	* @return True on match, false otherwise.	204	* @return True on match, false otherwise.
205	*/	205	*/
206	static bool match_component(tmpfs_dentry_t dentry, const char component)	206	static bool match_component(tmpfs_dentry_t dentry, const char component)
207	{	207	{
208	return !strcmp(dentry->name, component);	208	return !strcmp(dentry->name, component);
209	}	209	}
210		210
211	static unsigned long create_node(tmpfs_dentry_t *dentry,	211	static unsigned long create_node(tmpfs_dentry_t *dentry,
212	const char *component, int lflag)	212	const char *component, int lflag)
213	{	213	{
214	return 0;	214	return 0;
215	}	215	}
216		216
217	static int destroy_component(tmpfs_dentry_t *dentry)	217	static int destroy_component(tmpfs_dentry_t *dentry)
218	{	218	{
219	return EPERM;	219	return EPERM;
220	}	220	}
221		221
222	void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request)	222	void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request)
223	{	223	{
224	unsigned next = IPC_GET_ARG1(*request);	224	unsigned next = IPC_GET_ARG1(*request);
225	unsigned last = IPC_GET_ARG2(*request);	225	unsigned last = IPC_GET_ARG2(*request);
226	int dev_handle = IPC_GET_ARG3(*request);	226	int dev_handle = IPC_GET_ARG3(*request);
227	int lflag = IPC_GET_ARG4(*request);	227	int lflag = IPC_GET_ARG4(*request);
228		228
229	if (last < next)	229	if (last < next)
230	last += PLB_SIZE;	230	last += PLB_SIZE;
231		231
232	/*	232	/*
233	* Initialize TMPFS.	233	* Initialize TMPFS.
234	*/	234	*/
235	if (!root && !tmpfs_init()) {	235	if (!root && !tmpfs_init()) {
236	ipc_answer_0(rid, ENOMEM);	236	ipc_answer_0(rid, ENOMEM);
237	return;	237	return;
238	}	238	}
239		239
240	tmpfs_dentry_t *dtmp = root->child;	240	tmpfs_dentry_t *dtmp = root->child;
241	tmpfs_dentry_t *dcur = root;	241	tmpfs_dentry_t *dcur = root;
242		242
243	if (PLB_GET_CHAR(next) == '/')	243	if (PLB_GET_CHAR(next) == '/')
244	next++; /* eat slash */	244	next++; /* eat slash */
245		245
246	char component[NAME_MAX + 1];	246	char component[NAME_MAX + 1];
247	int len = 0;	247	int len = 0;
248	while (next <= last) {	248	while (dtmp && next <= last) {
249		249
250	/* collect the component */	250	/* collect the component */
251	if (PLB_GET_CHAR(next) != '/') {	251	if (PLB_GET_CHAR(next) != '/') {
252	if (len + 1 == NAME_MAX) {	252	if (len + 1 == NAME_MAX) {
253	/* comopnent length overflow */	253	/* comopnent length overflow */
254	ipc_answer_0(rid, ENAMETOOLONG);	254	ipc_answer_0(rid, ENAMETOOLONG);
255	return;	255	return;
256	}	256	}
257	component[len++] = PLB_GET_CHAR(next);	257	component[len++] = PLB_GET_CHAR(next);
258	next++; /* process next character */	258	next++; /* process next character */
259	if (next <= last)	259	if (next <= last)
260	continue;	260	continue;
261	}	261	}
262		262
263	assert(len);	263	assert(len);
264	component[len] = '\0';	264	component[len] = '\0';
265	next++; /* eat slash */	265	next++; /* eat slash */
266	len = 0;	266	len = 0;
267		267
268	/* match the component */	268	/* match the component */
269	while (dtmp && !match_component(dtmp, component))	269	while (dtmp && !match_component(dtmp, component))
270	dtmp = dtmp->sibling;	270	dtmp = dtmp->sibling;
271		271
272	/* handle miss: match amongst siblings */	272	/* handle miss: match amongst siblings */
273	if (!dtmp) {	273	if (!dtmp) {
274	if ((next > last) && (lflag & L_CREATE)) {	274	if ((next > last) && (lflag & L_CREATE)) {
275	/* no components left and L_CREATE specified */	275	/* no components left and L_CREATE specified */
276	if (dcur->type != TMPFS_DIRECTORY) {	276	if (dcur->type != TMPFS_DIRECTORY) {
277	ipc_answer_0(rid, ENOTDIR);	277	ipc_answer_0(rid, ENOTDIR);
278	return;	278	return;
279	}	279	}
280	unsigned long index = create_node(dcur,	280	unsigned long index = create_node(dcur,
281	component, lflag);	281	component, lflag);
282	if (index) {	282	if (index) {
283	ipc_answer_4(rid, EOK,	283	ipc_answer_4(rid, EOK,
284	tmpfs_reg.fs_handle, dev_handle,	284	tmpfs_reg.fs_handle, dev_handle,
285	index, 0);	285	index, 0);
286	} else {	286	} else {
287	ipc_answer_0(rid, ENOSPC);	287	ipc_answer_0(rid, ENOSPC);
288	}	288	}
289	return;	289	return;
290	}	290	}
291	ipc_answer_0(rid, ENOENT);	291	ipc_answer_0(rid, ENOENT);
292	return;	292	return;
293	}	293	}
294		294
295	/* descent one level */	295	/* descent one level */
296	dcur = dtmp;	296	dcur = dtmp;
297	dtmp = dtmp->child;	297	dtmp = dtmp->child;
-		298	}
298		299
299	/* handle miss: excessive components */	300	/* handle miss: excessive components */
300	if (!dtmp && next <= last) {	301	if (!dtmp && next <= last) {
301	if (lflag & L_CREATE) {	302	if (lflag & L_CREATE) {
302	if (dcur->type != TMPFS_DIRECTORY) {	303	if (dcur->type != TMPFS_DIRECTORY) {
303	ipc_answer_0(rid, ENOTDIR);	304	ipc_answer_0(rid, ENOTDIR);
-		305	return;
-		306	}
-		307
-		308	/* collect next component */
-		309	while (next <= last) {
-		310	if (PLB_GET_CHAR(next) == '/') {
-		311	/* more than one component */
-		312	ipc_answer_0(rid, ENOENT);
304	return;	313	return;
305	}	314	}
306		-
307	/* collect next component */	-
308	while (next <= last) {	-
309	if (PLB_GET_CHAR(next) == '/') {	-
310	/* more than one component */	-
311	ipc_answer_0(rid, ENOENT);	-
312	return;	-
313	}	-
314	if (len + 1 == NAME_MAX) {	315	if (len + 1 == NAME_MAX) {
315	/* component length overflow */	316	/* component length overflow */
316	ipc_answer_0(rid, ENAMETOOLONG);	317	ipc_answer_0(rid, ENAMETOOLONG);
317	return;	318	return;
318	}	-
319	component[len++] = PLB_GET_CHAR(next);	-
320	next++; /* process next character */	-
321	}	319	}
-		320	component[len++] = PLB_GET_CHAR(next);
-		321	next++; /* process next character */
-		322	}
322	assert(len);	323	assert(len);
323	component[len] = '\0';	324	component[len] = '\0';
324	len = 0;	325	len = 0;
325		326
326	unsigned long index;	327	unsigned long index;
327	index = create_node(dcur, component, lflag);	328	index = create_node(dcur, component, lflag);
328	if (index) {	329	if (index) {
329	ipc_answer_4(rid, EOK,	330	ipc_answer_4(rid, EOK, tmpfs_reg.fs_handle,
330	tmpfs_reg.fs_handle, dev_handle,	-
331	index, 0);	331	dev_handle, index, 0);
332	} else {	332	} else {
333	ipc_answer_0(rid, ENOSPC);	333	ipc_answer_0(rid, ENOSPC);
334	}	-
335	return;	-
336	}	334	}
337	ipc_answer_0(rid, ENOENT);	-
338	return;	335	return;
339	}	336	}
-		337	ipc_answer_0(rid, ENOENT);
340		338	return;
341	}	339	}
342		340
343	/* handle hit */	341	/* handle hit */
344	if (lflag & L_DESTROY) {	342	if (lflag & L_DESTROY) {
345	int res = destroy_component(dcur);	343	int res = destroy_component(dcur);
346	ipc_answer_0(rid, res);	344	ipc_answer_0(rid, res);
347	return;	345	return;
348	}	346	}
349	if ((lflag & (L_CREATE \| L_EXCLUSIVE)) == (L_CREATE \| L_EXCLUSIVE)) {	347	if ((lflag & (L_CREATE \| L_EXCLUSIVE)) == (L_CREATE \| L_EXCLUSIVE)) {
350	ipc_answer_0(rid, EEXIST);	348	ipc_answer_0(rid, EEXIST);
351	return;	349	return;
352	}	350	}
353	if ((lflag & L_FILE) && (dcur->type != TMPFS_FILE)) {	351	if ((lflag & L_FILE) && (dcur->type != TMPFS_FILE)) {
354	ipc_answer_0(rid, EISDIR);	352	ipc_answer_0(rid, EISDIR);
355	return;	353	return;
356	}	354	}
357	if ((lflag & L_DIRECTORY) && (dcur->type != TMPFS_DIRECTORY)) {	355	if ((lflag & L_DIRECTORY) && (dcur->type != TMPFS_DIRECTORY)) {
358	ipc_answer_0(rid, ENOTDIR);	356	ipc_answer_0(rid, ENOTDIR);
359	return;	357	return;
360	}	358	}
361		359
362	ipc_answer_4(rid, EOK, tmpfs_reg.fs_handle, dev_handle, dcur->index,	360	ipc_answer_4(rid, EOK, tmpfs_reg.fs_handle, dev_handle, dcur->index,
363	dcur->size);	361	dcur->size);
364	}	362	}
365		363
366	void tmpfs_read(ipc_callid_t rid, ipc_call_t *request)	364	void tmpfs_read(ipc_callid_t rid, ipc_call_t *request)
367	{	365	{
368	int dev_handle = IPC_GET_ARG1(*request);	366	int dev_handle = IPC_GET_ARG1(*request);
369	unsigned long index = IPC_GET_ARG2(*request);	367	unsigned long index = IPC_GET_ARG2(*request);
370	off_t pos = IPC_GET_ARG3(*request);	368	off_t pos = IPC_GET_ARG3(*request);
371		369
372	/*	370	/*
373	* Lookup the respective dentry.	371	* Lookup the respective dentry.
374	*/	372	*/
375	link_t *hlp;	373	link_t *hlp;
376	hlp = hash_table_find(&dentries, &index);	374	hlp = hash_table_find(&dentries, &index);
377	if (!hlp) {	375	if (!hlp) {
378	ipc_answer_0(rid, ENOENT);	376	ipc_answer_0(rid, ENOENT);
379	return;	377	return;
380	}	378	}
381	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,	379	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
382	dh_link);	380	dh_link);
383		381
384	/*	382	/*
385	* Receive the read request.	383	* Receive the read request.
386	*/	384	*/
387	ipc_callid_t callid;	385	ipc_callid_t callid;
388	size_t len;	386	size_t len;
389	if (!ipc_data_read_receive(&callid, &len)) {	387	if (!ipc_data_read_receive(&callid, &len)) {
390	ipc_answer_0(callid, EINVAL);	388	ipc_answer_0(callid, EINVAL);
391	ipc_answer_0(rid, EINVAL);	389	ipc_answer_0(rid, EINVAL);
392	return;	390	return;
393	}	391	}
394		392
395	size_t bytes;	393	size_t bytes;
396	if (dentry->type == TMPFS_FILE) {	394	if (dentry->type == TMPFS_FILE) {
397	bytes = max(0, min(dentry->size - pos, len));	395	bytes = max(0, min(dentry->size - pos, len));
398	(void) ipc_data_read_finalize(callid, dentry->data + pos,	396	(void) ipc_data_read_finalize(callid, dentry->data + pos,
399	bytes);	397	bytes);
400	} else {	398	} else {
401	int i;	399	int i;
402	tmpfs_dentry_t *cur = dentry->child;	400	tmpfs_dentry_t *cur = dentry->child;
403		401
404	assert(dentry->type == TMPFS_DIRECTORY);	402	assert(dentry->type == TMPFS_DIRECTORY);
405		403
406	/*	404	/*
407	* Yes, we really use O(n) algorithm here.	405	* Yes, we really use O(n) algorithm here.
408	* If it bothers someone, it could be fixed by introducing a	406	* If it bothers someone, it could be fixed by introducing a
409	* hash table.	407	* hash table.
410	*/	408	*/
411	for (i = 0, cur = dentry->child; i < pos && cur; i++,	409	for (i = 0, cur = dentry->child; i < pos && cur; i++,
412	cur = cur->sibling)	410	cur = cur->sibling)
413	;	411	;
414		412
415	if (!cur) {	413	if (!cur) {
416	ipc_answer_0(callid, ENOENT);	414	ipc_answer_0(callid, ENOENT);
417	ipc_answer_1(rid, ENOENT, 0);	415	ipc_answer_1(rid, ENOENT, 0);
418	return;	416	return;
419	}	417	}
420		418
421	(void) ipc_data_read_finalize(callid, cur->name,	419	(void) ipc_data_read_finalize(callid, cur->name,
422	strlen(cur->name) + 1);	420	strlen(cur->name) + 1);
423	bytes = 1;	421	bytes = 1;
424	}	422	}
425		423
426	/*	424	/*
427	* Answer the VFS_READ call.	425	* Answer the VFS_READ call.
428	*/	426	*/
429	ipc_answer_1(rid, EOK, bytes);	427	ipc_answer_1(rid, EOK, bytes);
430	}	428	}
431		429
432	void tmpfs_write(ipc_callid_t rid, ipc_call_t *request)	430	void tmpfs_write(ipc_callid_t rid, ipc_call_t *request)
433	{	431	{
434	int dev_handle = IPC_GET_ARG1(*request);	432	int dev_handle = IPC_GET_ARG1(*request);
435	unsigned long index = IPC_GET_ARG2(*request);	433	unsigned long index = IPC_GET_ARG2(*request);
436	off_t pos = IPC_GET_ARG3(*request);	434	off_t pos = IPC_GET_ARG3(*request);
437		435
438	/*	436	/*
439	* Lookup the respective dentry.	437	* Lookup the respective dentry.
440	*/	438	*/
441	link_t *hlp;	439	link_t *hlp;
442	hlp = hash_table_find(&dentries, &index);	440	hlp = hash_table_find(&dentries, &index);
443	if (!hlp) {	441	if (!hlp) {
444	ipc_answer_0(rid, ENOENT);	442	ipc_answer_0(rid, ENOENT);
445	return;	443	return;
446	}	444	}
447	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,	445	tmpfs_dentry_t *dentry = hash_table_get_instance(hlp, tmpfs_dentry_t,
448	dh_link);	446	dh_link);
449		447
450	/*	448	/*
451	* Receive the write request.	449	* Receive the write request.
452	*/	450	*/
453	ipc_callid_t callid;	451	ipc_callid_t callid;
454	size_t len;	452	size_t len;
455	if (!ipc_data_write_receive(&callid, &len)) {	453	if (!ipc_data_write_receive(&callid, &len)) {
456	ipc_answer_0(callid, EINVAL);	454	ipc_answer_0(callid, EINVAL);
457	ipc_answer_0(rid, EINVAL);	455	ipc_answer_0(rid, EINVAL);
458	return;	456	return;
459	}	457	}
460		458
461	/*	459	/*
462	* Check whether the file needs to grow.	460	* Check whether the file needs to grow.
463	*/	461	*/
464	if (pos + len <= dentry->size) {	462	if (pos + len <= dentry->size) {
465	/* The file size is not changing. */	463	/* The file size is not changing. */
466	(void) ipc_data_write_finalize(callid, dentry->data + pos, len);	464	(void) ipc_data_write_finalize(callid, dentry->data + pos, len);
467	ipc_answer_1(rid, EOK, len);	465	ipc_answer_1(rid, EOK, len);
468	return;	466	return;
469	}	467	}
470	size_t delta = (pos + len) - dentry->size;	468	size_t delta = (pos + len) - dentry->size;
471	/*	469	/*
472	* At this point, we are deliberately extremely straightforward and	470	* At this point, we are deliberately extremely straightforward and
473	* simply realloc the contents of the file on every write that grows the	471	* simply realloc the contents of the file on every write that grows the
474	* file. In the end, the situation might not be as bad as it may look:	472	* file. In the end, the situation might not be as bad as it may look:
475	* our heap allocator can save us and just grow the block whenever	473	* our heap allocator can save us and just grow the block whenever
476	* possible.	474	* possible.
477	*/	475	*/
478	void *newdata = realloc(dentry->data, dentry->size + delta);	476	void *newdata = realloc(dentry->data, dentry->size + delta);
479	if (!newdata) {	477	if (!newdata) {
480	ipc_answer_0(callid, ENOMEM);	478	ipc_answer_0(callid, ENOMEM);
481	ipc_answer_1(rid, EOK, 0);	479	ipc_answer_1(rid, EOK, 0);
482	return;	480	return;
483	}	481	}
484	/* Clear any newly allocated memory in order to emulate gaps. */	482	/* Clear any newly allocated memory in order to emulate gaps. */
485	memset(newdata + dentry->size, 0, delta);	483	memset(newdata + dentry->size, 0, delta);
486	dentry->size += delta;	484	dentry->size += delta;
487	dentry->data = newdata;	485	dentry->data = newdata;

Subversion Repositories HelenOS

(root)/trunk/uspace/srv/fs/tmpfs/tmpfs_ops.c @ 3517 – Rev 2705 → 2706