WebSVN – HelenOS – Diff – /branches/g5/uspace/srv/vfs/vfs_register.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    vfs_register.c
 * @brief
 */
 
#include <ipc/ipc.h>
#include <ipc/services.h>
#include <async.h>
#include <fibril.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <bool.h>
#include <futex.h>
#include <libadt/list.h>
#include <as.h>
#include <assert.h>
#include <atomic.h>
#include "vfs.h"
 
atomic_t fs_head_futex = FUTEX_INITIALIZER;
link_t fs_head;
 
atomic_t fs_handle_next = {
    .count = 1
};
 
/** Verify the VFS info structure.
 *
 * @param info      Info structure to be verified.
 *
 * @return      Non-zero if the info structure is sane, zero otherwise.
 */
static bool vfs_info_sane(vfs_info_t *info)
{
    int i;
 
    /*
     * Check if the name is non-empty and is composed solely of ASCII
     * characters [a-z]+[a-z0-9_-]*.
     */
    if (!islower(info->name[0])) {
        dprintf("The name doesn't start with a lowercase character.\n");
        return false;
    }
    for (i = 1; i < FS_NAME_MAXLEN; i++) {
        if (!(islower(info->name[i]) || isdigit(info->name[i])) &&
            (info->name[i] != '-') && (info->name[i] != '_')) {
            if (info->name[i] == '\0') {
                break;
            } else {
                dprintf("The name contains illegal "
                    "characters.\n");
                return false;
            }
        }
    }
    /*
     * This check is not redundant. It ensures that the name is
     * NULL-terminated, even if FS_NAME_MAXLEN characters are used.
     */
    if (info->name[i] != '\0') {
        dprintf("The name is not properly NULL-terminated.\n");
        return false;
    }
   
 
    /*
     * Check if the FS implements mandatory VFS operations.
     */
    if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] != VFS_OP_DEFINED) {
        dprintf("Operation VFS_LOOKUP not defined by the client.\n");
        return false;
    }
 
 
 
 
 
 
 
 
    if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_READ)] != VFS_OP_DEFINED) {
        dprintf("Operation VFS_READ not defined by the client.\n");
        return false;
    }
   
    /*
     * Check if each operation is either not defined, defined or default.
     */
    for (i = VFS_FIRST; i < VFS_LAST_CLNT; i++) {
        if ((info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_NULL) &&
            (info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFAULT) &&
            (info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFINED)) {
            dprintf("Operation info not understood.\n");
            return false;
        }
    }
    return true;
}
 
/** VFS_REGISTER protocol function.
 *
 * @param rid       Hash of the call with the request.
 * @param request   Call structure with the request.
 */
void vfs_register(ipc_callid_t rid, ipc_call_t *request)
{
    ipc_callid_t callid;
    ipc_call_t call;
    int rc;
    size_t size;
 
    dprintf("Processing VFS_REGISTER request received from %p.\n",
        request->in_phone_hash);
 
    /*
     * The first call has to be IPC_M_DATA_SEND in which we receive the
     * VFS info structure from the client FS.
     */
    if (!ipc_data_write_receive(&callid, &size)) {
        /*
         * The client doesn't obey the same protocol as we do.
         */
        dprintf("Receiving of VFS info failed.\n");
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
   
    dprintf("VFS info received, size = %d\n", size);
   
    /*
     * We know the size of the VFS info structure. See if the client
     * understands this easy concept too.
     */
    if (size != sizeof(vfs_info_t)) {
        /*
         * The client is sending us something, which cannot be
         * the info structure.
         */
        dprintf("Received VFS info has bad size.\n");
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
 
    /*
     * Allocate and initialize a buffer for the fs_info structure.
     */
    fs_info_t *fs_info;
    fs_info = (fs_info_t *) malloc(sizeof(fs_info_t));
    if (!fs_info) {
        dprintf("Could not allocate memory for FS info.\n");
        ipc_answer_0(callid, ENOMEM);
        ipc_answer_0(rid, ENOMEM);
        return;
    }
    link_initialize(&fs_info->fs_link);
    futex_initialize(&fs_info->phone_futex, 1);
       
    rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size);
    if (rc != EOK) {
        dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n",
            rc);
        free(fs_info);
        ipc_answer_0(callid, rc);
        ipc_answer_0(rid, rc);
        return;
    }
 
    dprintf("VFS info delivered.\n");
       
    if (!vfs_info_sane(&fs_info->vfs_info)) {
        free(fs_info);
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
       
    futex_down(&fs_head_futex);
 
    /*
     * Check for duplicit registrations.
     */
    if (fs_name_to_handle(fs_info->vfs_info.name, false)) {
        /*
         * We already register a fs like this.
         */
        dprintf("FS is already registered.\n");
        futex_up(&fs_head_futex);
        free(fs_info);
        ipc_answer_0(callid, EEXISTS);
        ipc_answer_0(rid, EEXISTS);
        return;
    }
 
    /*
     * Add fs_info to the list of registered FS's.
     */
    dprintf("Inserting FS into the list of registered file systems.\n");
    list_append(&fs_info->fs_link, &fs_head);
 
    /*
     * Now we want the client to send us the IPC_M_CONNECT_TO_ME call so
     * that a callback connection is created and we have a phone through
     * which to forward VFS requests to it.
     */
    callid = async_get_call(&call);
    if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) {
        dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
        list_remove(&fs_info->fs_link);
        futex_up(&fs_head_futex);
        free(fs_info);
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
    fs_info->phone = IPC_GET_ARG5(call);
    ipc_answer_0(callid, EOK);
 
    dprintf("Callback connection to FS created.\n");
 
    /*
     * The client will want us to send him the address space area with PLB.
     */
 
    if (!ipc_share_in_receive(&callid, &size)) {
        dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
        list_remove(&fs_info->fs_link);
        futex_up(&fs_head_futex);
        ipc_hangup(fs_info->phone);
        free(fs_info);
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
   
    /*
     * We can only send the client address space area PLB_SIZE bytes long.
     */
    if (size != PLB_SIZE) {
        dprintf("Client suggests wrong size of PFB, size = %d\n", size);
        list_remove(&fs_info->fs_link);
        futex_up(&fs_head_futex);
        ipc_hangup(fs_info->phone);
        free(fs_info);
        ipc_answer_0(callid, EINVAL);
        ipc_answer_0(rid, EINVAL);
        return;
    }
 
    /*
     * Commit to read-only sharing the PLB with the client.
     */
    (void) ipc_share_in_finalize(callid, plb,
        AS_AREA_READ | AS_AREA_CACHEABLE);
 
    dprintf("Sharing PLB.\n");
 
    /*
     * That was it. The FS has been registered.
     * In reply to the VFS_REGISTER request, we assign the client file
     * system a global file system handle.
     */
    fs_info->fs_handle = (int) atomic_postinc(&fs_handle_next);
    ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle);
   
    futex_up(&fs_head_futex);
   
    dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n",
        FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle);
}
 
/** For a given file system handle, implement policy for allocating a phone.
 *
 * @param handle    File system handle.
 *
 * @return      Phone over which a multi-call request can be safely
 *          sent. Return 0 if no phone was found.
 */
int vfs_grab_phone(int handle)
{
    /*
     * For now, we don't try to be very clever and very fast.
     * We simply lookup the phone in the fs_head list. We currently don't
     * open any additional phones (even though that itself would be pretty
     * straightforward; housekeeping multiple open phones to a FS task would
     * be more demanding). Instead, we simply take the respective
     * phone_futex and keep it until vfs_release_phone().
     */
    futex_down(&fs_head_futex);
    link_t *cur;
    fs_info_t *fs;
    for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
        fs = list_get_instance(cur, fs_info_t, fs_link);
        if (fs->fs_handle == handle) {
            futex_up(&fs_head_futex);
            /*
             * For now, take the futex unconditionally.
             * Oh yeah, serialization rocks.
             * It will be up'ed in vfs_release_phone().
             */
            futex_down(&fs->phone_futex);
            /*
             * Avoid deadlock with other fibrils in the same thread
             * by disabling fibril preemption.
             */
            fibril_inc_sercount();
            return fs->phone;
        }
    }
    futex_up(&fs_head_futex);
    return 0;
}
 
/** Tell VFS that the phone is in use for any request.
 *
 * @param phone     Phone to FS task.
 */
void vfs_release_phone(int phone)
{
    bool found = false;
 
    /*
     * Undo the fibril_inc_sercount() done in vfs_grab_phone().
     */
    fibril_dec_sercount();
   
    futex_down(&fs_head_futex);
    link_t *cur;
    for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
        fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
        if (fs->phone == phone) {
            found = true;
            futex_up(&fs_head_futex);
            futex_up(&fs->phone_futex);
            return;
        }
    }
    futex_up(&fs_head_futex);
 
    /*
     * Not good to get here.
     */
    assert(found == true);
}
 
/** Convert file system name to its handle.
 *
 * @param name      File system name.
 * @param lock      If true, the function will down and up the
 *          fs_head_futex.
 *
 * @return      File system handle or zero if file system not found.
 */
int fs_name_to_handle(char *name, bool lock)
{
    int handle = 0;
   
    if (lock)
        futex_down(&fs_head_futex);
    link_t *cur;
    for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
        fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
        if (strncmp(fs->vfs_info.name, name,
            sizeof(fs->vfs_info.name)) == 0) {
            handle = fs->fs_handle;
            break;
        }
    }
    if (lock)
        futex_up(&fs_head_futex);
    return handle;
}
 
/**
 * @}
 */
 

Rev 2698	Rev 2731
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 vfs_register.c	34	* @file vfs_register.c
35	* @brief	35	* @brief
36	*/	36	*/
37		37
38	#include <ipc/ipc.h>	38	#include <ipc/ipc.h>
39	#include <ipc/services.h>	39	#include <ipc/services.h>
40	#include <async.h>	40	#include <async.h>
41	#include <fibril.h>	41	#include <fibril.h>
42	#include <errno.h>	42	#include <errno.h>
43	#include <stdio.h>	43	#include <stdio.h>
44	#include <stdlib.h>	44	#include <stdlib.h>
45	#include <string.h>	45	#include <string.h>
46	#include <ctype.h>	46	#include <ctype.h>
47	#include <bool.h>	47	#include <bool.h>
48	#include <futex.h>	48	#include <futex.h>
49	#include <libadt/list.h>	49	#include <libadt/list.h>
50	#include <as.h>	50	#include <as.h>
51	#include <assert.h>	51	#include <assert.h>
52	#include <atomic.h>	52	#include <atomic.h>
53	#include "vfs.h"	53	#include "vfs.h"
54		54
55	atomic_t fs_head_futex = FUTEX_INITIALIZER;	55	atomic_t fs_head_futex = FUTEX_INITIALIZER;
56	link_t fs_head;	56	link_t fs_head;
57		57
58	atomic_t fs_handle_next = {	58	atomic_t fs_handle_next = {
59	.count = 1	59	.count = 1
60	};	60	};
61		61
62	/** Verify the VFS info structure.	62	/** Verify the VFS info structure.
63	*	63	*
64	* @param info Info structure to be verified.	64	* @param info Info structure to be verified.
65	*	65	*
66	* @return Non-zero if the info structure is sane, zero otherwise.	66	* @return Non-zero if the info structure is sane, zero otherwise.
67	*/	67	*/
68	static bool vfs_info_sane(vfs_info_t *info)	68	static bool vfs_info_sane(vfs_info_t *info)
69	{	69	{
70	int i;	70	int i;
71		71
72	/*	72	/*
73	* Check if the name is non-empty and is composed solely of ASCII	73	* Check if the name is non-empty and is composed solely of ASCII
74	* characters [a-z]+[a-z0-9_-]*.	74	* characters [a-z]+[a-z0-9_-]*.
75	*/	75	*/
76	if (!islower(info->name[0])) {	76	if (!islower(info->name[0])) {
77	dprintf("The name doesn't start with a lowercase character.\n");	77	dprintf("The name doesn't start with a lowercase character.\n");
78	return false;	78	return false;
79	}	79	}
80	for (i = 1; i < FS_NAME_MAXLEN; i++) {	80	for (i = 1; i < FS_NAME_MAXLEN; i++) {
81	if (!(islower(info->name[i]) \|\| isdigit(info->name[i])) &&	81	if (!(islower(info->name[i]) \|\| isdigit(info->name[i])) &&
82	(info->name[i] != '-') && (info->name[i] != '_')) {	82	(info->name[i] != '-') && (info->name[i] != '_')) {
83	if (info->name[i] == '\0') {	83	if (info->name[i] == '\0') {
84	break;	84	break;
85	} else {	85	} else {
86	dprintf("The name contains illegal "	86	dprintf("The name contains illegal "
87	"characters.\n");	87	"characters.\n");
88	return false;	88	return false;
89	}	89	}
90	}	90	}
91	}	91	}
92	/*	92	/*
93	* This check is not redundant. It ensures that the name is	93	* This check is not redundant. It ensures that the name is
94	* NULL-terminated, even if FS_NAME_MAXLEN characters are used.	94	* NULL-terminated, even if FS_NAME_MAXLEN characters are used.
95	*/	95	*/
96	if (info->name[i] != '\0') {	96	if (info->name[i] != '\0') {
97	dprintf("The name is not properly NULL-terminated.\n");	97	dprintf("The name is not properly NULL-terminated.\n");
98	return false;	98	return false;
99	}	99	}
100		100
101		101
102	/*	102	/*
103	* Check if the FS implements mandatory VFS operations.	103	* Check if the FS implements mandatory VFS operations.
104	*/	104	*/
105	if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] != VFS_OP_DEFINED) {	105	if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] != VFS_OP_DEFINED) {
106	dprintf("Operation VFS_LOOKUP not defined by the client.\n");	106	dprintf("Operation VFS_LOOKUP not defined by the client.\n");
107	return false;	107	return false;
108	}	108	}
109	if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_OPEN)] != VFS_OP_DEFINED) {	-
110	dprintf("Operation VFS_OPEN not defined by the client.\n");	-
111	return false;	-
112	}	-
113	if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_CLOSE)] != VFS_OP_DEFINED) {	-
114	dprintf("Operation VFS_CLOSE not defined by the client.\n");	-
115	return false;	-
116	}	-
117	if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_READ)] != VFS_OP_DEFINED) {	109	if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_READ)] != VFS_OP_DEFINED) {
118	dprintf("Operation VFS_READ not defined by the client.\n");	110	dprintf("Operation VFS_READ not defined by the client.\n");
119	return false;	111	return false;
120	}	112	}
121		113
122	/*	114	/*
123	* Check if each operation is either not defined, defined or default.	115	* Check if each operation is either not defined, defined or default.
124	*/	116	*/
125	for (i = VFS_FIRST; i < VFS_LAST_CLNT; i++) {	117	for (i = VFS_FIRST; i < VFS_LAST_CLNT; i++) {
126	if ((info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_NULL) &&	118	if ((info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_NULL) &&
127	(info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFAULT) &&	119	(info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFAULT) &&
128	(info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFINED)) {	120	(info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFINED)) {
129	dprintf("Operation info not understood.\n");	121	dprintf("Operation info not understood.\n");
130	return false;	122	return false;
131	}	123	}
132	}	124	}
133	return true;	125	return true;
134	}	126	}
135		127
136	/** VFS_REGISTER protocol function.	128	/** VFS_REGISTER protocol function.
137	*	129	*
138	* @param rid Hash of the call with the request.	130	* @param rid Hash of the call with the request.
139	* @param request Call structure with the request.	131	* @param request Call structure with the request.
140	*/	132	*/
141	void vfs_register(ipc_callid_t rid, ipc_call_t *request)	133	void vfs_register(ipc_callid_t rid, ipc_call_t *request)
142	{	134	{
143	ipc_callid_t callid;	135	ipc_callid_t callid;
144	ipc_call_t call;	136	ipc_call_t call;
145	int rc;	137	int rc;
146	size_t size;	138	size_t size;
147		139
148	dprintf("Processing VFS_REGISTER request received from %p.\n",	140	dprintf("Processing VFS_REGISTER request received from %p.\n",
149	request->in_phone_hash);	141	request->in_phone_hash);
150		142
151	/*	143	/*
152	* The first call has to be IPC_M_DATA_SEND in which we receive the	144	* The first call has to be IPC_M_DATA_SEND in which we receive the
153	* VFS info structure from the client FS.	145	* VFS info structure from the client FS.
154	*/	146	*/
155	if (!ipc_data_write_receive(&callid, &size)) {	147	if (!ipc_data_write_receive(&callid, &size)) {
156	/*	148	/*
157	* The client doesn't obey the same protocol as we do.	149	* The client doesn't obey the same protocol as we do.
158	*/	150	*/
159	dprintf("Receiving of VFS info failed.\n");	151	dprintf("Receiving of VFS info failed.\n");
160	ipc_answer_0(callid, EINVAL);	152	ipc_answer_0(callid, EINVAL);
161	ipc_answer_0(rid, EINVAL);	153	ipc_answer_0(rid, EINVAL);
162	return;	154	return;
163	}	155	}
164		156
165	dprintf("VFS info received, size = %d\n", size);	157	dprintf("VFS info received, size = %d\n", size);
166		158
167	/*	159	/*
168	* We know the size of the VFS info structure. See if the client	160	* We know the size of the VFS info structure. See if the client
169	* understands this easy concept too.	161	* understands this easy concept too.
170	*/	162	*/
171	if (size != sizeof(vfs_info_t)) {	163	if (size != sizeof(vfs_info_t)) {
172	/*	164	/*
173	* The client is sending us something, which cannot be	165	* The client is sending us something, which cannot be
174	* the info structure.	166	* the info structure.
175	*/	167	*/
176	dprintf("Received VFS info has bad size.\n");	168	dprintf("Received VFS info has bad size.\n");
177	ipc_answer_0(callid, EINVAL);	169	ipc_answer_0(callid, EINVAL);
178	ipc_answer_0(rid, EINVAL);	170	ipc_answer_0(rid, EINVAL);
179	return;	171	return;
180	}	172	}
181		173
182	/*	174	/*
183	* Allocate and initialize a buffer for the fs_info structure.	175	* Allocate and initialize a buffer for the fs_info structure.
184	*/	176	*/
185	fs_info_t *fs_info;	177	fs_info_t *fs_info;
186	fs_info = (fs_info_t *) malloc(sizeof(fs_info_t));	178	fs_info = (fs_info_t *) malloc(sizeof(fs_info_t));
187	if (!fs_info) {	179	if (!fs_info) {
188	dprintf("Could not allocate memory for FS info.\n");	180	dprintf("Could not allocate memory for FS info.\n");
189	ipc_answer_0(callid, ENOMEM);	181	ipc_answer_0(callid, ENOMEM);
190	ipc_answer_0(rid, ENOMEM);	182	ipc_answer_0(rid, ENOMEM);
191	return;	183	return;
192	}	184	}
193	link_initialize(&fs_info->fs_link);	185	link_initialize(&fs_info->fs_link);
194	futex_initialize(&fs_info->phone_futex, 1);	186	futex_initialize(&fs_info->phone_futex, 1);
195		187
196	rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size);	188	rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size);
197	if (rc != EOK) {	189	if (rc != EOK) {
198	dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n",	190	dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n",
199	rc);	191	rc);
200	free(fs_info);	192	free(fs_info);
201	ipc_answer_0(callid, rc);	193	ipc_answer_0(callid, rc);
202	ipc_answer_0(rid, rc);	194	ipc_answer_0(rid, rc);
203	return;	195	return;
204	}	196	}
205		197
206	dprintf("VFS info delivered.\n");	198	dprintf("VFS info delivered.\n");
207		199
208	if (!vfs_info_sane(&fs_info->vfs_info)) {	200	if (!vfs_info_sane(&fs_info->vfs_info)) {
209	free(fs_info);	201	free(fs_info);
210	ipc_answer_0(callid, EINVAL);	202	ipc_answer_0(callid, EINVAL);
211	ipc_answer_0(rid, EINVAL);	203	ipc_answer_0(rid, EINVAL);
212	return;	204	return;
213	}	205	}
214		206
215	futex_down(&fs_head_futex);	207	futex_down(&fs_head_futex);
216		208
217	/*	209	/*
218	* Check for duplicit registrations.	210	* Check for duplicit registrations.
219	*/	211	*/
220	if (fs_name_to_handle(fs_info->vfs_info.name, false)) {	212	if (fs_name_to_handle(fs_info->vfs_info.name, false)) {
221	/*	213	/*
222	* We already register a fs like this.	214	* We already register a fs like this.
223	*/	215	*/
224	dprintf("FS is already registered.\n");	216	dprintf("FS is already registered.\n");
225	futex_up(&fs_head_futex);	217	futex_up(&fs_head_futex);
226	free(fs_info);	218	free(fs_info);
227	ipc_answer_0(callid, EEXISTS);	219	ipc_answer_0(callid, EEXISTS);
228	ipc_answer_0(rid, EEXISTS);	220	ipc_answer_0(rid, EEXISTS);
229	return;	221	return;
230	}	222	}
231		223
232	/*	224	/*
233	* Add fs_info to the list of registered FS's.	225	* Add fs_info to the list of registered FS's.
234	*/	226	*/
235	dprintf("Inserting FS into the list of registered file systems.\n");	227	dprintf("Inserting FS into the list of registered file systems.\n");
236	list_append(&fs_info->fs_link, &fs_head);	228	list_append(&fs_info->fs_link, &fs_head);
237		229
238	/*	230	/*
239	* Now we want the client to send us the IPC_M_CONNECT_TO_ME call so	231	* Now we want the client to send us the IPC_M_CONNECT_TO_ME call so
240	* that a callback connection is created and we have a phone through	232	* that a callback connection is created and we have a phone through
241	* which to forward VFS requests to it.	233	* which to forward VFS requests to it.
242	*/	234	*/
243	callid = async_get_call(&call);	235	callid = async_get_call(&call);
244	if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) {	236	if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) {
245	dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));	237	dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
246	list_remove(&fs_info->fs_link);	238	list_remove(&fs_info->fs_link);
247	futex_up(&fs_head_futex);	239	futex_up(&fs_head_futex);
248	free(fs_info);	240	free(fs_info);
249	ipc_answer_0(callid, EINVAL);	241	ipc_answer_0(callid, EINVAL);
250	ipc_answer_0(rid, EINVAL);	242	ipc_answer_0(rid, EINVAL);
251	return;	243	return;
252	}	244	}
253	fs_info->phone = IPC_GET_ARG5(call);	245	fs_info->phone = IPC_GET_ARG5(call);
254	ipc_answer_0(callid, EOK);	246	ipc_answer_0(callid, EOK);
255		247
256	dprintf("Callback connection to FS created.\n");	248	dprintf("Callback connection to FS created.\n");
257		249
258	/*	250	/*
259	* The client will want us to send him the address space area with PLB.	251	* The client will want us to send him the address space area with PLB.
260	*/	252	*/
261		253
262	if (!ipc_share_in_receive(&callid, &size)) {	254	if (!ipc_share_in_receive(&callid, &size)) {
263	dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));	255	dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
264	list_remove(&fs_info->fs_link);	256	list_remove(&fs_info->fs_link);
265	futex_up(&fs_head_futex);	257	futex_up(&fs_head_futex);
266	ipc_hangup(fs_info->phone);	258	ipc_hangup(fs_info->phone);
267	free(fs_info);	259	free(fs_info);
268	ipc_answer_0(callid, EINVAL);	260	ipc_answer_0(callid, EINVAL);
269	ipc_answer_0(rid, EINVAL);	261	ipc_answer_0(rid, EINVAL);
270	return;	262	return;
271	}	263	}
272		264
273	/*	265	/*
274	* We can only send the client address space area PLB_SIZE bytes long.	266	* We can only send the client address space area PLB_SIZE bytes long.
275	*/	267	*/
276	if (size != PLB_SIZE) {	268	if (size != PLB_SIZE) {
277	dprintf("Client suggests wrong size of PFB, size = %d\n", size);	269	dprintf("Client suggests wrong size of PFB, size = %d\n", size);
278	list_remove(&fs_info->fs_link);	270	list_remove(&fs_info->fs_link);
279	futex_up(&fs_head_futex);	271	futex_up(&fs_head_futex);
280	ipc_hangup(fs_info->phone);	272	ipc_hangup(fs_info->phone);
281	free(fs_info);	273	free(fs_info);
282	ipc_answer_0(callid, EINVAL);	274	ipc_answer_0(callid, EINVAL);
283	ipc_answer_0(rid, EINVAL);	275	ipc_answer_0(rid, EINVAL);
284	return;	276	return;
285	}	277	}
286		278
287	/*	279	/*
288	* Commit to read-only sharing the PLB with the client.	280	* Commit to read-only sharing the PLB with the client.
289	*/	281	*/
290	(void) ipc_share_in_finalize(callid, plb,	282	(void) ipc_share_in_finalize(callid, plb,
291	AS_AREA_READ \| AS_AREA_CACHEABLE);	283	AS_AREA_READ \| AS_AREA_CACHEABLE);
292		284
293	dprintf("Sharing PLB.\n");	285	dprintf("Sharing PLB.\n");
294		286
295	/*	287	/*
296	* That was it. The FS has been registered.	288	* That was it. The FS has been registered.
297	* In reply to the VFS_REGISTER request, we assign the client file	289	* In reply to the VFS_REGISTER request, we assign the client file
298	* system a global file system handle.	290	* system a global file system handle.
299	*/	291	*/
300	fs_info->fs_handle = (int) atomic_postinc(&fs_handle_next);	292	fs_info->fs_handle = (int) atomic_postinc(&fs_handle_next);
301	ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle);	293	ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle);
302		294
303	futex_up(&fs_head_futex);	295	futex_up(&fs_head_futex);
304		296
305	dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n",	297	dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n",
306	FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle);	298	FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle);
307	}	299	}
308		300
309	/** For a given file system handle, implement policy for allocating a phone.	301	/** For a given file system handle, implement policy for allocating a phone.
310	*	302	*
311	* @param handle File system handle.	303	* @param handle File system handle.
312	*	304	*
313	* @return Phone over which a multi-call request can be safely	305	* @return Phone over which a multi-call request can be safely
314	* sent. Return 0 if no phone was found.	306	* sent. Return 0 if no phone was found.
315	*/	307	*/
316	int vfs_grab_phone(int handle)	308	int vfs_grab_phone(int handle)
317	{	309	{
318	/*	310	/*
319	* For now, we don't try to be very clever and very fast.	311	* For now, we don't try to be very clever and very fast.
320	* We simply lookup the phone in the fs_head list. We currently don't	312	* We simply lookup the phone in the fs_head list. We currently don't
321	* open any additional phones (even though that itself would be pretty	313	* open any additional phones (even though that itself would be pretty
322	* straightforward; housekeeping multiple open phones to a FS task would	314	* straightforward; housekeeping multiple open phones to a FS task would
323	* be more demanding). Instead, we simply take the respective	315	* be more demanding). Instead, we simply take the respective
324	* phone_futex and keep it until vfs_release_phone().	316	* phone_futex and keep it until vfs_release_phone().
325	*/	317	*/
326	futex_down(&fs_head_futex);	318	futex_down(&fs_head_futex);
327	link_t *cur;	319	link_t *cur;
328	fs_info_t *fs;	320	fs_info_t *fs;
329	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {	321	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
330	fs = list_get_instance(cur, fs_info_t, fs_link);	322	fs = list_get_instance(cur, fs_info_t, fs_link);
331	if (fs->fs_handle == handle) {	323	if (fs->fs_handle == handle) {
332	futex_up(&fs_head_futex);	324	futex_up(&fs_head_futex);
333	/*	325	/*
334	* For now, take the futex unconditionally.	326	* For now, take the futex unconditionally.
335	* Oh yeah, serialization rocks.	327	* Oh yeah, serialization rocks.
336	* It will be up'ed in vfs_release_phone().	328	* It will be up'ed in vfs_release_phone().
337	*/	329	*/
338	futex_down(&fs->phone_futex);	330	futex_down(&fs->phone_futex);
339	/*	331	/*
340	* Avoid deadlock with other fibrils in the same thread	332	* Avoid deadlock with other fibrils in the same thread
341	* by disabling fibril preemption.	333	* by disabling fibril preemption.
342	*/	334	*/
343	fibril_inc_sercount();	335	fibril_inc_sercount();
344	return fs->phone;	336	return fs->phone;
345	}	337	}
346	}	338	}
347	futex_up(&fs_head_futex);	339	futex_up(&fs_head_futex);
348	return 0;	340	return 0;
349	}	341	}
350		342
351	/** Tell VFS that the phone is in use for any request.	343	/** Tell VFS that the phone is in use for any request.
352	*	344	*
353	* @param phone Phone to FS task.	345	* @param phone Phone to FS task.
354	*/	346	*/
355	void vfs_release_phone(int phone)	347	void vfs_release_phone(int phone)
356	{	348	{
357	bool found = false;	349	bool found = false;
358		350
359	/*	351	/*
360	* Undo the fibril_inc_sercount() done in vfs_grab_phone().	352	* Undo the fibril_inc_sercount() done in vfs_grab_phone().
361	*/	353	*/
362	fibril_dec_sercount();	354	fibril_dec_sercount();
363		355
364	futex_down(&fs_head_futex);	356	futex_down(&fs_head_futex);
365	link_t *cur;	357	link_t *cur;
366	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {	358	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
367	fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);	359	fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
368	if (fs->phone == phone) {	360	if (fs->phone == phone) {
369	found = true;	361	found = true;
370	futex_up(&fs_head_futex);	362	futex_up(&fs_head_futex);
371	futex_up(&fs->phone_futex);	363	futex_up(&fs->phone_futex);
372	return;	364	return;
373	}	365	}
374	}	366	}
375	futex_up(&fs_head_futex);	367	futex_up(&fs_head_futex);
376		368
377	/*	369	/*
378	* Not good to get here.	370	* Not good to get here.
379	*/	371	*/
380	assert(found == true);	372	assert(found == true);
381	}	373	}
382		374
383	/** Convert file system name to its handle.	375	/** Convert file system name to its handle.
384	*	376	*
385	* @param name File system name.	377	* @param name File system name.
386	* @param lock If true, the function will down and up the	378	* @param lock If true, the function will down and up the
387	* fs_head_futex.	379	* fs_head_futex.
388	*	380	*
389	* @return File system handle or zero if file system not found.	381	* @return File system handle or zero if file system not found.
390	*/	382	*/
391	int fs_name_to_handle(char *name, bool lock)	383	int fs_name_to_handle(char *name, bool lock)
392	{	384	{
393	int handle = 0;	385	int handle = 0;
394		386
395	if (lock)	387	if (lock)
396	futex_down(&fs_head_futex);	388	futex_down(&fs_head_futex);
397	link_t *cur;	389	link_t *cur;
398	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {	390	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
399	fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);	391	fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
400	if (strncmp(fs->vfs_info.name, name,	392	if (strncmp(fs->vfs_info.name, name,
401	sizeof(fs->vfs_info.name)) == 0) {	393	sizeof(fs->vfs_info.name)) == 0) {
402	handle = fs->fs_handle;	394	handle = fs->fs_handle;
403	break;	395	break;
404	}	396	}
405	}	397	}
406	if (lock)	398	if (lock)
407	futex_up(&fs_head_futex);	399	futex_up(&fs_head_futex);
408	return handle;	400	return handle;
409	}	401	}
410		402
411	/**	403	/**
412	* @}	404	* @}
413	*/	405	*/
414		406

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(root)/branches/g5/uspace/srv/vfs/vfs_register.c @ 3800 – Rev 2698 → 2731