WebSVN – HelenOS – Diff – /trunk/uspace/srv/vfs/vfs_rdwr.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_rdwr.c
 * @brief
 */
 
#include "vfs.h"
#include <ipc/ipc.h>
#include <async.h>
#include <errno.h>
#include <rwlock.h>
#include <unistd.h>
 
static void vfs_rdwr(ipc_callid_t rid, ipc_call_t *request, bool read)
{
 
    /*
     * The following code strongly depends on the fact that the files data
     * structure can be only accessed by a single fibril and all file
     * operations are serialized (i.e. the reads and writes cannot
     * interleave and a file cannot be closed while it is being read).
     *
     * Additional synchronization needs to be added once the table of
     * open files supports parallel access!
     */
 
    int fd = IPC_GET_ARG1(*request);
 
    /*
     * Lookup the file structure corresponding to the file descriptor.
     */
    vfs_file_t *file = vfs_file_get(fd);
    if (!file) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
 
    /*
     * Now we need to receive a call with client's
     * IPC_M_DATA_READ/IPC_M_DATA_WRITE request.
     */
    ipc_callid_t callid;
    int res;
    if (read)
        res = ipc_data_read_receive(&callid, NULL);
    else
        res = ipc_data_write_receive(&callid, NULL);
    if (!res) {
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
 
    /*
     * Lock the open file structure so that no other thread can manipulate
     * the same open file at a time.
     */
    futex_down(&file->lock);
 
    /*
     * Lock the file's node so that no other client can read/write to it at
     * the same time.
     */
    if (read)
        rwlock_reader_lock(&file->node->contents_rwlock);
    else
        rwlock_writer_lock(&file->node->contents_rwlock);
 
    int fs_phone = vfs_grab_phone(file->node->fs_handle);  
   
    /*
     * Make a VFS_READ/VFS_WRITE request at the destination FS server.
     */
    aid_t msg;
    ipc_call_t answer;
    msg = async_send_3(fs_phone, IPC_GET_METHOD(*request),
        file->node->dev_handle, file->node->index, file->pos, &answer);
   
    /*
     * Forward the IPC_M_DATA_READ/IPC_M_DATA_WRITE request to the
     * destination FS server. The call will be routed as if sent by
     * ourselves. Note that call arguments are immutable in this case so we
     * don't have to bother.
     */
    ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
 
    vfs_release_phone(fs_phone);
 
    /*
     * Wait for reply from the FS server.
     */
    ipcarg_t rc;
    async_wait_for(msg, &rc);
    size_t bytes = IPC_GET_ARG1(answer);
 
    /*
     * Unlock the VFS node.
     */
    if (read)
        rwlock_reader_unlock(&file->node->contents_rwlock);
    else {
        /* Update the cached version of node's size. */
        file->node->size = IPC_GET_ARG2(answer);
        rwlock_writer_unlock(&file->node->contents_rwlock);
    }
 
    /*
     * Update the position pointer and unlock the open file.
     */
    file->pos += bytes;
    futex_up(&file->lock);
 
    /*
     * FS server's reply is the final result of the whole operation we
     * return to the client.
     */
    ipc_answer_1(rid, rc, bytes);
}
 
 
void vfs_read(ipc_callid_t rid, ipc_call_t *request)
{
    vfs_rdwr(rid, request, true);
}
 
void vfs_write(ipc_callid_t rid, ipc_call_t *request)
{
    vfs_rdwr(rid, request, false);
}
 
void vfs_seek(ipc_callid_t rid, ipc_call_t *request)
{
    int fd = (int) IPC_GET_ARG1(*request);
    off_t off = (off_t) IPC_GET_ARG2(*request);
    int whence = (int) IPC_GET_ARG3(*request);
 
 
    /*
     * Lookup the file structure corresponding to the file descriptor.
     */
    vfs_file_t *file = vfs_file_get(fd);
    if (!file) {
        ipc_answer_0(rid, ENOENT);
        return;
    }
 
    off_t newpos;
    futex_down(&file->lock);
    if (whence == SEEK_SET) {
        file->pos = off;
        futex_up(&file->lock);
        ipc_answer_1(rid, EOK, off);
        return;
    }
    if (whence == SEEK_CUR) {
        if (file->pos + off < file->pos) {
            futex_up(&file->lock);
            ipc_answer_0(rid, EOVERFLOW);
            return;
        }
        file->pos += off;
        newpos = file->pos;
        futex_up(&file->lock);
        ipc_answer_1(rid, EOK, newpos);
        return;
    }
    if (whence == SEEK_END) {
        rwlock_reader_lock(&file->node->contents_rwlock);
        size_t size = file->node->size;
        rwlock_reader_unlock(&file->node->contents_rwlock);
        if (size + off < size) {
            futex_up(&file->lock);
            ipc_answer_0(rid, EOVERFLOW);
            return;
        }
        newpos = size + off;
        futex_up(&file->lock);
        ipc_answer_1(rid, EOK, newpos);
        return;
    }
    futex_up(&file->lock);
    ipc_answer_0(rid, EINVAL);
}
 
/**
 * @}
 */
 

Rev 2684	Rev 2687
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_rdwr.c	34	* @file vfs_rdwr.c
35	* @brief	35	* @brief
36	*/	36	*/
37		37
38	#include "vfs.h"	38	#include "vfs.h"
39	#include <ipc/ipc.h>	39	#include <ipc/ipc.h>
40	#include <async.h>	40	#include <async.h>
41	#include <errno.h>	41	#include <errno.h>
42	#include <rwlock.h>	42	#include <rwlock.h>
43	#include <unistd.h>	43	#include <unistd.h>
44		44
45	static void vfs_rdwr(ipc_callid_t rid, ipc_call_t *request, bool read)	45	static void vfs_rdwr(ipc_callid_t rid, ipc_call_t *request, bool read)
46	{	46	{
47		47
48	/*	48	/*
49	* The following code strongly depends on the fact that the files data	49	* The following code strongly depends on the fact that the files data
50	* structure can be only accessed by a single fibril and all file	50	* structure can be only accessed by a single fibril and all file
51	* operations are serialized (i.e. the reads and writes cannot	51	* operations are serialized (i.e. the reads and writes cannot
52	* interleave and a file cannot be closed while it is being read).	52	* interleave and a file cannot be closed while it is being read).
53	*	53	*
54	* Additional synchronization needs to be added once the table of	54	* Additional synchronization needs to be added once the table of
55	* open files supports parallel access!	55	* open files supports parallel access!
56	*/	56	*/
57		57
58	int fd = IPC_GET_ARG1(*request);	58	int fd = IPC_GET_ARG1(*request);
59		59
60	/*	60	/*
61	* Lookup the file structure corresponding to the file descriptor.	61	* Lookup the file structure corresponding to the file descriptor.
62	*/	62	*/
63	vfs_file_t *file = vfs_file_get(fd);	63	vfs_file_t *file = vfs_file_get(fd);
64	if (!file) {	64	if (!file) {
65	ipc_answer_0(rid, ENOENT);	65	ipc_answer_0(rid, ENOENT);
66	return;	66	return;
67	}	67	}
68		68
69	/*	69	/*
70	* Now we need to receive a call with client's	70	* Now we need to receive a call with client's
71	* IPC_M_DATA_READ/IPC_M_DATA_WRITE request.	71	* IPC_M_DATA_READ/IPC_M_DATA_WRITE request.
72	*/	72	*/
73	ipc_callid_t callid;	73	ipc_callid_t callid;
74	int res;	74	int res;
75	if (read)	75	if (read)
76	res = ipc_data_read_receive(&callid, NULL);	76	res = ipc_data_read_receive(&callid, NULL);
77	else	77	else
78	res = ipc_data_write_receive(&callid, NULL);	78	res = ipc_data_write_receive(&callid, NULL);
79	if (!res) {	79	if (!res) {
80	ipc_answer_0(callid, EINVAL);	80	ipc_answer_0(callid, EINVAL);
81	ipc_answer_0(rid, EINVAL);	81	ipc_answer_0(rid, EINVAL);
82	return;	82	return;
83	}	83	}
84		84
85	/*	85	/*
86	* Lock the open file structure so that no other thread can manipulate	86	* Lock the open file structure so that no other thread can manipulate
87	* the same open file at a time.	87	* the same open file at a time.
88	*/	88	*/
89	futex_down(&file->lock);	89	futex_down(&file->lock);
90		90
91	/*	91	/*
92	* Lock the file's node so that no other client can read/write to it at	92	* Lock the file's node so that no other client can read/write to it at
93	* the same time.	93	* the same time.
94	*/	94	*/
95	if (read)	95	if (read)
96	rwlock_reader_lock(&file->node->contents_rwlock);	96	rwlock_reader_lock(&file->node->contents_rwlock);
97	else	97	else
98	rwlock_writer_lock(&file->node->contents_rwlock);	98	rwlock_writer_lock(&file->node->contents_rwlock);
99		99
100	int fs_phone = vfs_grab_phone(file->node->fs_handle);	100	int fs_phone = vfs_grab_phone(file->node->fs_handle);
101		101
102	/*	102	/*
103	* Make a VFS_READ/VFS_WRITE request at the destination FS server.	103	* Make a VFS_READ/VFS_WRITE request at the destination FS server.
104	*/	104	*/
105	aid_t msg;	105	aid_t msg;
106	ipc_call_t answer;	106	ipc_call_t answer;
107	msg = async_send_3(fs_phone, IPC_GET_METHOD(*request),	107	msg = async_send_3(fs_phone, IPC_GET_METHOD(*request),
108	file->node->dev_handle, file->node->index, file->pos, &answer);	108	file->node->dev_handle, file->node->index, file->pos, &answer);
109		109
110	/*	110	/*
111	* Forward the IPC_M_DATA_READ/IPC_M_DATA_WRITE request to the	111	* Forward the IPC_M_DATA_READ/IPC_M_DATA_WRITE request to the
112	* destination FS server. The call will be routed as if sent by	112	* destination FS server. The call will be routed as if sent by
113	* ourselves. Note that call arguments are immutable in this case so we	113	* ourselves. Note that call arguments are immutable in this case so we
114	* don't have to bother.	114	* don't have to bother.
115	*/	115	*/
116	ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);	116	ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
117		117
118	vfs_release_phone(fs_phone);	118	vfs_release_phone(fs_phone);
119		119
120	/*	120	/*
121	* Wait for reply from the FS server.	121	* Wait for reply from the FS server.
122	*/	122	*/
123	ipcarg_t rc;	123	ipcarg_t rc;
124	async_wait_for(msg, &rc);	124	async_wait_for(msg, &rc);
125	size_t bytes = IPC_GET_ARG1(answer);	125	size_t bytes = IPC_GET_ARG1(answer);
126		126
127	/*	127	/*
128	* Unlock the VFS node.	128	* Unlock the VFS node.
129	*/	129	*/
130	if (read)	130	if (read)
131	rwlock_reader_unlock(&file->node->contents_rwlock);	131	rwlock_reader_unlock(&file->node->contents_rwlock);
132	else	132	else {
-		133	/* Update the cached version of node's size. */
-		134	file->node->size = IPC_GET_ARG2(answer);
133	rwlock_writer_unlock(&file->node->contents_rwlock);	135	rwlock_writer_unlock(&file->node->contents_rwlock);
-		136	}
134		137
135	/*	138	/*
136	* Update the position pointer and unlock the open file.	139	* Update the position pointer and unlock the open file.
137	*/	140	*/
138	file->pos += bytes;	141	file->pos += bytes;
139	futex_up(&file->lock);	142	futex_up(&file->lock);
140		143
141	/*	144	/*
142	* FS server's reply is the final result of the whole operation we	145	* FS server's reply is the final result of the whole operation we
143	* return to the client.	146	* return to the client.
144	*/	147	*/
145	ipc_answer_1(rid, rc, bytes);	148	ipc_answer_1(rid, rc, bytes);
146	}	149	}
147		150
148		151
149	void vfs_read(ipc_callid_t rid, ipc_call_t *request)	152	void vfs_read(ipc_callid_t rid, ipc_call_t *request)
150	{	153	{
151	vfs_rdwr(rid, request, true);	154	vfs_rdwr(rid, request, true);
152	}	155	}
153		156
154	void vfs_write(ipc_callid_t rid, ipc_call_t *request)	157	void vfs_write(ipc_callid_t rid, ipc_call_t *request)
155	{	158	{
156	vfs_rdwr(rid, request, false);	159	vfs_rdwr(rid, request, false);
157	}	160	}
158		161
159	void vfs_seek(ipc_callid_t rid, ipc_call_t *request)	162	void vfs_seek(ipc_callid_t rid, ipc_call_t *request)
160	{	163	{
161	int fd = (int) IPC_GET_ARG1(*request);	164	int fd = (int) IPC_GET_ARG1(*request);
162	off_t off = (off_t) IPC_GET_ARG2(*request);	165	off_t off = (off_t) IPC_GET_ARG2(*request);
163	int whence = (int) IPC_GET_ARG3(*request);	166	int whence = (int) IPC_GET_ARG3(*request);
164		167
165		168
166	/*	169	/*
167	* Lookup the file structure corresponding to the file descriptor.	170	* Lookup the file structure corresponding to the file descriptor.
168	*/	171	*/
169	vfs_file_t *file = vfs_file_get(fd);	172	vfs_file_t *file = vfs_file_get(fd);
170	if (!file) {	173	if (!file) {
171	ipc_answer_0(rid, ENOENT);	174	ipc_answer_0(rid, ENOENT);
172	return;	175	return;
173	}	176	}
174		177
175	off_t newpos;	178	off_t newpos;
176	futex_down(&file->lock);	179	futex_down(&file->lock);
177	if (whence == SEEK_SET) {	180	if (whence == SEEK_SET) {
178	file->pos = off;	181	file->pos = off;
179	futex_up(&file->lock);	182	futex_up(&file->lock);
180	ipc_answer_1(rid, EOK, off);	183	ipc_answer_1(rid, EOK, off);
181	return;	184	return;
182	}	185	}
183	if (whence == SEEK_CUR) {	186	if (whence == SEEK_CUR) {
184	if (file->pos + off < file->pos) {	187	if (file->pos + off < file->pos) {
185	futex_up(&file->lock);	188	futex_up(&file->lock);
186	ipc_answer_0(rid, EOVERFLOW);	189	ipc_answer_0(rid, EOVERFLOW);
187	return;	190	return;
188	}	191	}
189	file->pos += off;	192	file->pos += off;
190	newpos = file->pos;	193	newpos = file->pos;
191	futex_up(&file->lock);	194	futex_up(&file->lock);
192	ipc_answer_1(rid, EOK, newpos);	195	ipc_answer_1(rid, EOK, newpos);
193	return;	196	return;
194	}	197	}
195	if (whence == SEEK_END) {	198	if (whence == SEEK_END) {
196	rwlock_reader_lock(&file->node->contents_rwlock);	199	rwlock_reader_lock(&file->node->contents_rwlock);
197	size_t size = file->node->size;	200	size_t size = file->node->size;
198	rwlock_reader_unlock(&file->node->contents_rwlock);	201	rwlock_reader_unlock(&file->node->contents_rwlock);
199	if (size + off < size) {	202	if (size + off < size) {
200	futex_up(&file->lock);	203	futex_up(&file->lock);
201	ipc_answer_0(rid, EOVERFLOW);	204	ipc_answer_0(rid, EOVERFLOW);
202	return;	205	return;
203	}	206	}
204	newpos = size + off;	207	newpos = size + off;
205	futex_up(&file->lock);	208	futex_up(&file->lock);
206	ipc_answer_1(rid, EOK, newpos);	209	ipc_answer_1(rid, EOK, newpos);
207	return;	210	return;
208	}	211	}
209	futex_up(&file->lock);	212	futex_up(&file->lock);
210	ipc_answer_0(rid, EINVAL);	213	ipc_answer_0(rid, EINVAL);
211	}	214	}
212		215
213	/**	216	/**
214	* @}	217	* @}
215	*/	218	*/
216		219

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(root)/trunk/uspace/srv/vfs/vfs_rdwr.c – Rev 2684 → 2687