WebSVN – HelenOS – Diff – /branches/tracing/uspace/srv/vfs/vfs_file.c


/*
 * Copyright (c) 2007 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    vfs_file.c
 * @brief   Various operations on files have their home in this file.
 */
 
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <bool.h>
#include <fibril.h>
#include <fibril_sync.h>
#include "vfs.h"
 
/**
 * This is a per-connection table of open files.
 * Our assumption is that each client opens only one connection and therefore
 * there is one table of open files per task. However, this may not be the case
 * and the client can open more connections to VFS. In that case, there will be
 * several tables and several file handle name spaces per task. Besides of this,
 * the functionality will stay unchanged. So unless the client knows what it is
 * doing, it should open one connection to VFS only.
 *
 * Allocation of the open files table is deferred until the client makes the
 * first VFS_OPEN operation.
 *
 * This resource being per-connection and, in the first place, per-fibril, we
 * don't need to protect it by a mutex.
 */
fibril_local vfs_file_t **files = NULL;
 
/** Initialize the table of open files. */
bool vfs_files_init(void)
{
    if (!files) {
        files = malloc(MAX_OPEN_FILES * sizeof(vfs_file_t *));
        if (!files)
            return false;
        memset(files, 0, MAX_OPEN_FILES * sizeof(vfs_file_t *));
    }
    return true;
}
 
/** Allocate a file descriptor.
 *
 * @return      First available file descriptor or a negative error
 *          code.
 */
int vfs_fd_alloc(void)
{
    if (!vfs_files_init())
        return ENOMEM;
   
    unsigned int i;
    for (i = 0; i < MAX_OPEN_FILES; i++) {
        if (!files[i]) {
            files[i] = (vfs_file_t *) malloc(sizeof(vfs_file_t));
            if (!files[i])
                return ENOMEM;
           
            memset(files[i], 0, sizeof(vfs_file_t));
            fibril_mutex_initialize(&files[i]->lock);
            vfs_file_addref(files[i]);
            return (int) i;
        }
    }
   
    return EMFILE;
}
 
/** Release file descriptor.
 *
 * @param fd        File descriptor being released.
 *
 * @return      EOK on success or EBADF if fd is an invalid file
 *          descriptor.
 */
int vfs_fd_free(int fd)
{
    if (!vfs_files_init())
        return ENOMEM;
   
    if ((fd < 0) || (fd >= MAX_OPEN_FILES) || (files[fd] == NULL))
        return EBADF;
   
    vfs_file_delref(files[fd]);
    files[fd] = NULL;
   
    return EOK;
}
 
/** Increment reference count of VFS file structure.
 *
 * @param file      File structure that will have reference count
 *          incremented.
 */
void vfs_file_addref(vfs_file_t *file)
{
    /*
     * File structures are per-connection, so no-one, except the current
     * fibril, should have a reference to them. This is the reason we don't
     * do any synchronization here.
     */
    file->refcnt++;
}
 
/** Decrement reference count of VFS file structure.
 *
 * @param file      File structure that will have reference count
 *          decremented.
 */
void vfs_file_delref(vfs_file_t *file)
{
    if (file->refcnt-- == 1) {
        /*
         * Lost the last reference to a file, need to drop our reference
         * to the underlying VFS node.
         */
        vfs_node_delref(file->node);
        free(file);
    }
}
 
/** Find VFS file structure for a given file descriptor.
 *
 * @param fd        File descriptor.
 *
 * @return      VFS file structure corresponding to fd.
 */
vfs_file_t *vfs_file_get(int fd)
{
    if (!vfs_files_init())
        return NULL;
   
    if ((fd >= 0) && (fd < MAX_OPEN_FILES))
        return files[fd];
   
    return NULL;
}
 
/**
 * @}
 */
 

Rev 4377	Rev 4692
1	/*	1	/*
2	* Copyright (c) 2007 Jakub Jermar	2	* Copyright (c) 2007 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 vfs_file.c	34	* @file vfs_file.c
35	* @brief Various operations on files have their home in this file.	35	* @brief Various operations on files have their home in this file.
36	*/	36	*/
37		37
38	#include <errno.h>	38	#include <errno.h>
39	#include <stdlib.h>	39	#include <stdlib.h>
40	#include <string.h>	40	#include <string.h>
41	#include <assert.h>	41	#include <assert.h>
42	#include <bool.h>	42	#include <bool.h>
-		43	#include <fibril.h>
-		44	#include <fibril_sync.h>
43	#include "vfs.h"	45	#include "vfs.h"
44		46
45	/**	47	/**
46	* This is a per-connection table of open files.	48	* This is a per-connection table of open files.
47	* Our assumption is that each client opens only one connection and therefore	49	* Our assumption is that each client opens only one connection and therefore
48	* there is one table of open files per task. However, this may not be the case	50	* there is one table of open files per task. However, this may not be the case
49	* and the client can open more connections to VFS. In that case, there will be	51	* and the client can open more connections to VFS. In that case, there will be
50	* several tables and several file handle name spaces per task. Besides of this,	52	* several tables and several file handle name spaces per task. Besides of this,
51	* the functionality will stay unchanged. So unless the client knows what it is	53	* the functionality will stay unchanged. So unless the client knows what it is
52	* doing, it should open one connection to VFS only.	54	* doing, it should open one connection to VFS only.
53	*	55	*
54	* Allocation of the open files table is deferred until the client makes the	56	* Allocation of the open files table is deferred until the client makes the
55	* first VFS_OPEN operation.	57	* first VFS_OPEN operation.
56	*	58	*
57	* This resource being per-connection and, in the first place, per-fibril, we	59	* This resource being per-connection and, in the first place, per-fibril, we
58	* don't need to protect it by a futex.	60	* don't need to protect it by a mutex.
59	*/	61	*/
60	__thread vfs_file_t **files = NULL;	62	fibril_local vfs_file_t **files = NULL;
61		63
62	/** Initialize the table of open files. */	64	/** Initialize the table of open files. */
63	bool vfs_files_init(void)	65	bool vfs_files_init(void)
64	{	66	{
65	if (!files) {	67	if (!files) {
66	files = malloc(MAX_OPEN_FILES * sizeof(vfs_file_t *));	68	files = malloc(MAX_OPEN_FILES * sizeof(vfs_file_t *));
67	if (!files)	69	if (!files)
68	return false;	70	return false;
69	memset(files, 0, MAX_OPEN_FILES * sizeof(vfs_file_t *));	71	memset(files, 0, MAX_OPEN_FILES * sizeof(vfs_file_t *));
70	}	72	}
71	return true;	73	return true;
72	}	74	}
73		75
74	/** Allocate a file descriptor.	76	/** Allocate a file descriptor.
75	*	77	*
76	* @return First available file descriptor or a negative error	78	* @return First available file descriptor or a negative error
77	* code.	79	* code.
78	*/	80	*/
79	int vfs_fd_alloc(void)	81	int vfs_fd_alloc(void)
80	{	82	{
-		83	if (!vfs_files_init())
81	int i;	84	return ENOMEM;
82		85
-		86	unsigned int i;
83	for (i = 0; i < MAX_OPEN_FILES; i++) {	87	for (i = 0; i < MAX_OPEN_FILES; i++) {
84	if (!files[i]) {	88	if (!files[i]) {
85	files[i] = (vfs_file_t *) malloc(sizeof(vfs_file_t));	89	files[i] = (vfs_file_t *) malloc(sizeof(vfs_file_t));
86	if (!files[i])	90	if (!files[i])
87	return ENOMEM;	91	return ENOMEM;
-		92
88	memset(files[i], 0, sizeof(vfs_file_t));	93	memset(files[i], 0, sizeof(vfs_file_t));
89	futex_initialize(&files[i]->lock, 1);	94	fibril_mutex_initialize(&files[i]->lock);
90	vfs_file_addref(files[i]);	95	vfs_file_addref(files[i]);
91	return i;	96	return (int) i;
92	}	97	}
93	}	98	}
-		99
94	return EMFILE;	100	return EMFILE;
95	}	101	}
96		102
97	/** Release file descriptor.	103	/** Release file descriptor.
98	*	104	*
99	* @param fd File descriptor being released.	105	* @param fd File descriptor being released.
100	*	106	*
101	* @return EOK on success or EBADF if fd is an invalid file	107	* @return EOK on success or EBADF if fd is an invalid file
102	* descriptor.	108	* descriptor.
103	*/	109	*/
104	int vfs_fd_free(int fd)	110	int vfs_fd_free(int fd)
105	{	111	{
-		112	if (!vfs_files_init())
-		113	return ENOMEM;
-		114
106	if ((fd < 0) \|\| (fd >= MAX_OPEN_FILES) \|\| (files[fd] == NULL))	115	if ((fd < 0) \|\| (fd >= MAX_OPEN_FILES) \|\| (files[fd] == NULL))
107	return EBADF;	116	return EBADF;
-		117
108	vfs_file_delref(files[fd]);	118	vfs_file_delref(files[fd]);
109	files[fd] = NULL;	119	files[fd] = NULL;
-		120
110	return EOK;	121	return EOK;
111	}	122	}
112		123
113	/** Increment reference count of VFS file structure.	124	/** Increment reference count of VFS file structure.
114	*	125	*
115	* @param file File structure that will have reference count	126	* @param file File structure that will have reference count
116	* incremented.	127	* incremented.
117	*/	128	*/
118	void vfs_file_addref(vfs_file_t *file)	129	void vfs_file_addref(vfs_file_t *file)
119	{	130	{
120	/*	131	/*
121	* File structures are per-connection, so no-one, except the current	132	* File structures are per-connection, so no-one, except the current
122	* fibril, should have a reference to them. This is the reason we don't	133	* fibril, should have a reference to them. This is the reason we don't
123	* do any synchronization here.	134	* do any synchronization here.
124	*/	135	*/
125	file->refcnt++;	136	file->refcnt++;
126	}	137	}
127		138
128	/** Decrement reference count of VFS file structure.	139	/** Decrement reference count of VFS file structure.
129	*	140	*
130	* @param file File structure that will have reference count	141	* @param file File structure that will have reference count
131	* decremented.	142	* decremented.
132	*/	143	*/
133	void vfs_file_delref(vfs_file_t *file)	144	void vfs_file_delref(vfs_file_t *file)
134	{	145	{
135	if (file->refcnt-- == 1) {	146	if (file->refcnt-- == 1) {
136	/*	147	/*
137	* Lost the last reference to a file, need to drop our reference	148	* Lost the last reference to a file, need to drop our reference
138	* to the underlying VFS node.	149	* to the underlying VFS node.
139	*/	150	*/
140	vfs_node_delref(file->node);	151	vfs_node_delref(file->node);
141	free(file);	152	free(file);
142	}	153	}
143	}	154	}
144		155
145	/** Find VFS file structure for a given file descriptor.	156	/** Find VFS file structure for a given file descriptor.
146	*	157	*
147	* @param fd File descriptor.	158	* @param fd File descriptor.
148	*	159	*
149	* @return VFS file structure corresponding to fd.	160	* @return VFS file structure corresponding to fd.
150	*/	161	*/
151	vfs_file_t *vfs_file_get(int fd)	162	vfs_file_t *vfs_file_get(int fd)
152	{	163	{
-		164	if (!vfs_files_init())
-		165	return NULL;
-		166
153	if ((fd >= 0) && (fd < MAX_OPEN_FILES))	167	if ((fd >= 0) && (fd < MAX_OPEN_FILES))
154	return files[fd];	168	return files[fd];
-		169
155	return NULL;	170	return NULL;
156	}	171	}
157		172
158	/**	173	/**
159	* @}	174	* @}
160	*/	175	*/
161		176

Subversion Repositories HelenOS

(root)/branches/tracing/uspace/srv/vfs/vfs_file.c – Rev 4377 → 4692