WebSVN – HelenOS – Diff – /branches/dynload/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;
    }
   
    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);
    fibril_inc_sercount();
 
    /*
     * 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");
        fibril_dec_sercount();
        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);
        fibril_dec_sercount();
        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);
        fibril_dec_sercount();
        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);
        fibril_dec_sercount();
        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 = (fs_handle_t) atomic_postinc(&fs_handle_next);
    ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle);
   
    fibril_dec_sercount();
    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);
   
    /* Process pending mount requests possibly waiting
     * for this filesystem implementation.
     */
    vfs_process_pending_mount();
}
 
/** 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(fs_handle_t 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.
 */
fs_handle_t 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 4341	Rev 4345
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	return true;	101	return true;
102	}	102	}
103		103
104	/** VFS_REGISTER protocol function.	104	/** VFS_REGISTER protocol function.
105	*	105	*
106	* @param rid Hash of the call with the request.	106	* @param rid Hash of the call with the request.
107	* @param request Call structure with the request.	107	* @param request Call structure with the request.
108	*/	108	*/
109	void vfs_register(ipc_callid_t rid, ipc_call_t *request)	109	void vfs_register(ipc_callid_t rid, ipc_call_t *request)
110	{	110	{
111	ipc_callid_t callid;	111	ipc_callid_t callid;
112	ipc_call_t call;	112	ipc_call_t call;
113	int rc;	113	int rc;
114	size_t size;	114	size_t size;
115		115
116	dprintf("Processing VFS_REGISTER request received from %p.\n",	116	dprintf("Processing VFS_REGISTER request received from %p.\n",
117	request->in_phone_hash);	117	request->in_phone_hash);
118		118
119	/*	119	/*
120	* The first call has to be IPC_M_DATA_SEND in which we receive the	120	* The first call has to be IPC_M_DATA_SEND in which we receive the
121	* VFS info structure from the client FS.	121	* VFS info structure from the client FS.
122	*/	122	*/
123	if (!ipc_data_write_receive(&callid, &size)) {	123	if (!ipc_data_write_receive(&callid, &size)) {
124	/*	124	/*
125	* The client doesn't obey the same protocol as we do.	125	* The client doesn't obey the same protocol as we do.
126	*/	126	*/
127	dprintf("Receiving of VFS info failed.\n");	127	dprintf("Receiving of VFS info failed.\n");
128	ipc_answer_0(callid, EINVAL);	128	ipc_answer_0(callid, EINVAL);
129	ipc_answer_0(rid, EINVAL);	129	ipc_answer_0(rid, EINVAL);
130	return;	130	return;
131	}	131	}
132		132
133	dprintf("VFS info received, size = %d\n", size);	133	dprintf("VFS info received, size = %d\n", size);
134		134
135	/*	135	/*
136	* We know the size of the VFS info structure. See if the client	136	* We know the size of the VFS info structure. See if the client
137	* understands this easy concept too.	137	* understands this easy concept too.
138	*/	138	*/
139	if (size != sizeof(vfs_info_t)) {	139	if (size != sizeof(vfs_info_t)) {
140	/*	140	/*
141	* The client is sending us something, which cannot be	141	* The client is sending us something, which cannot be
142	* the info structure.	142	* the info structure.
143	*/	143	*/
144	dprintf("Received VFS info has bad size.\n");	144	dprintf("Received VFS info has bad size.\n");
145	ipc_answer_0(callid, EINVAL);	145	ipc_answer_0(callid, EINVAL);
146	ipc_answer_0(rid, EINVAL);	146	ipc_answer_0(rid, EINVAL);
147	return;	147	return;
148	}	148	}
149		149
150	/*	150	/*
151	* Allocate and initialize a buffer for the fs_info structure.	151	* Allocate and initialize a buffer for the fs_info structure.
152	*/	152	*/
153	fs_info_t *fs_info;	153	fs_info_t *fs_info;
154	fs_info = (fs_info_t *) malloc(sizeof(fs_info_t));	154	fs_info = (fs_info_t *) malloc(sizeof(fs_info_t));
155	if (!fs_info) {	155	if (!fs_info) {
156	dprintf("Could not allocate memory for FS info.\n");	156	dprintf("Could not allocate memory for FS info.\n");
157	ipc_answer_0(callid, ENOMEM);	157	ipc_answer_0(callid, ENOMEM);
158	ipc_answer_0(rid, ENOMEM);	158	ipc_answer_0(rid, ENOMEM);
159	return;	159	return;
160	}	160	}
161	link_initialize(&fs_info->fs_link);	161	link_initialize(&fs_info->fs_link);
162	futex_initialize(&fs_info->phone_futex, 1);	162	futex_initialize(&fs_info->phone_futex, 1);
163		163
164	rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size);	164	rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size);
165	if (rc != EOK) {	165	if (rc != EOK) {
166	dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n",	166	dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n",
167	rc);	167	rc);
168	free(fs_info);	168	free(fs_info);
169	ipc_answer_0(callid, rc);	169	ipc_answer_0(callid, rc);
170	ipc_answer_0(rid, rc);	170	ipc_answer_0(rid, rc);
171	return;	171	return;
172	}	172	}
173		173
174	dprintf("VFS info delivered.\n");	174	dprintf("VFS info delivered.\n");
175		175
176	if (!vfs_info_sane(&fs_info->vfs_info)) {	176	if (!vfs_info_sane(&fs_info->vfs_info)) {
177	free(fs_info);	177	free(fs_info);
178	ipc_answer_0(callid, EINVAL);	178	ipc_answer_0(callid, EINVAL);
179	ipc_answer_0(rid, EINVAL);	179	ipc_answer_0(rid, EINVAL);
180	return;	180	return;
181	}	181	}
182		182
183	futex_down(&fs_head_futex);	183	futex_down(&fs_head_futex);
184	fibril_inc_sercount();	184	fibril_inc_sercount();
185		185
186	/*	186	/*
187	* Check for duplicit registrations.	187	* Check for duplicit registrations.
188	*/	188	*/
189	if (fs_name_to_handle(fs_info->vfs_info.name, false)) {	189	if (fs_name_to_handle(fs_info->vfs_info.name, false)) {
190	/*	190	/*
191	* We already register a fs like this.	191	* We already register a fs like this.
192	*/	192	*/
193	dprintf("FS is already registered.\n");	193	dprintf("FS is already registered.\n");
194	fibril_dec_sercount();	194	fibril_dec_sercount();
195	futex_up(&fs_head_futex);	195	futex_up(&fs_head_futex);
196	free(fs_info);	196	free(fs_info);
197	ipc_answer_0(callid, EEXISTS);	197	ipc_answer_0(callid, EEXISTS);
198	ipc_answer_0(rid, EEXISTS);	198	ipc_answer_0(rid, EEXISTS);
199	return;	199	return;
200	}	200	}
201		201
202	/*	202	/*
203	* Add fs_info to the list of registered FS's.	203	* Add fs_info to the list of registered FS's.
204	*/	204	*/
205	dprintf("Inserting FS into the list of registered file systems.\n");	205	dprintf("Inserting FS into the list of registered file systems.\n");
206	list_append(&fs_info->fs_link, &fs_head);	206	list_append(&fs_info->fs_link, &fs_head);
207		207
208	/*	208	/*
209	* Now we want the client to send us the IPC_M_CONNECT_TO_ME call so	209	* Now we want the client to send us the IPC_M_CONNECT_TO_ME call so
210	* that a callback connection is created and we have a phone through	210	* that a callback connection is created and we have a phone through
211	* which to forward VFS requests to it.	211	* which to forward VFS requests to it.
212	*/	212	*/
213	callid = async_get_call(&call);	213	callid = async_get_call(&call);
214	if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) {	214	if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) {
215	dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));	215	dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
216	list_remove(&fs_info->fs_link);	216	list_remove(&fs_info->fs_link);
217	fibril_dec_sercount();	217	fibril_dec_sercount();
218	futex_up(&fs_head_futex);	218	futex_up(&fs_head_futex);
219	free(fs_info);	219	free(fs_info);
220	ipc_answer_0(callid, EINVAL);	220	ipc_answer_0(callid, EINVAL);
221	ipc_answer_0(rid, EINVAL);	221	ipc_answer_0(rid, EINVAL);
222	return;	222	return;
223	}	223	}
224	fs_info->phone = IPC_GET_ARG5(call);	224	fs_info->phone = IPC_GET_ARG5(call);
225	ipc_answer_0(callid, EOK);	225	ipc_answer_0(callid, EOK);
226		226
227	dprintf("Callback connection to FS created.\n");	227	dprintf("Callback connection to FS created.\n");
228		228
229	/*	229	/*
230	* The client will want us to send him the address space area with PLB.	230	* The client will want us to send him the address space area with PLB.
231	*/	231	*/
232		232
233	if (!ipc_share_in_receive(&callid, &size)) {	233	if (!ipc_share_in_receive(&callid, &size)) {
234	dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));	234	dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
235	list_remove(&fs_info->fs_link);	235	list_remove(&fs_info->fs_link);
236	fibril_dec_sercount();	236	fibril_dec_sercount();
237	futex_up(&fs_head_futex);	237	futex_up(&fs_head_futex);
238	ipc_hangup(fs_info->phone);	238	ipc_hangup(fs_info->phone);
239	free(fs_info);	239	free(fs_info);
240	ipc_answer_0(callid, EINVAL);	240	ipc_answer_0(callid, EINVAL);
241	ipc_answer_0(rid, EINVAL);	241	ipc_answer_0(rid, EINVAL);
242	return;	242	return;
243	}	243	}
244		244
245	/*	245	/*
246	* We can only send the client address space area PLB_SIZE bytes long.	246	* We can only send the client address space area PLB_SIZE bytes long.
247	*/	247	*/
248	if (size != PLB_SIZE) {	248	if (size != PLB_SIZE) {
249	dprintf("Client suggests wrong size of PFB, size = %d\n", size);	249	dprintf("Client suggests wrong size of PFB, size = %d\n", size);
250	list_remove(&fs_info->fs_link);	250	list_remove(&fs_info->fs_link);
251	fibril_dec_sercount();	251	fibril_dec_sercount();
252	futex_up(&fs_head_futex);	252	futex_up(&fs_head_futex);
253	ipc_hangup(fs_info->phone);	253	ipc_hangup(fs_info->phone);
254	free(fs_info);	254	free(fs_info);
255	ipc_answer_0(callid, EINVAL);	255	ipc_answer_0(callid, EINVAL);
256	ipc_answer_0(rid, EINVAL);	256	ipc_answer_0(rid, EINVAL);
257	return;	257	return;
258	}	258	}
259		259
260	/*	260	/*
261	* Commit to read-only sharing the PLB with the client.	261	* Commit to read-only sharing the PLB with the client.
262	*/	262	*/
263	(void) ipc_share_in_finalize(callid, plb,	263	(void) ipc_share_in_finalize(callid, plb,
264	AS_AREA_READ \| AS_AREA_CACHEABLE);	264	AS_AREA_READ \| AS_AREA_CACHEABLE);
265		265
266	dprintf("Sharing PLB.\n");	266	dprintf("Sharing PLB.\n");
267		267
268	/*	268	/*
269	* That was it. The FS has been registered.	269	* That was it. The FS has been registered.
270	* In reply to the VFS_REGISTER request, we assign the client file	270	* In reply to the VFS_REGISTER request, we assign the client file
271	* system a global file system handle.	271	* system a global file system handle.
272	*/	272	*/
273	fs_info->fs_handle = (fs_handle_t) atomic_postinc(&fs_handle_next);	273	fs_info->fs_handle = (fs_handle_t) atomic_postinc(&fs_handle_next);
274	ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle);	274	ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle);
275		275
276	fibril_dec_sercount();	276	fibril_dec_sercount();
277	futex_up(&fs_head_futex);	277	futex_up(&fs_head_futex);
278		278
279	dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n",	279	dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n",
280	FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle);	280	FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle);
-		281
-		282	/* Process pending mount requests possibly waiting
-		283	* for this filesystem implementation.
-		284	*/
-		285	vfs_process_pending_mount();
281	}	286	}
282		287
283	/** For a given file system handle, implement policy for allocating a phone.	288	/** For a given file system handle, implement policy for allocating a phone.
284	*	289	*
285	* @param handle File system handle.	290	* @param handle File system handle.
286	*	291	*
287	* @return Phone over which a multi-call request can be safely	292	* @return Phone over which a multi-call request can be safely
288	* sent. Return 0 if no phone was found.	293	* sent. Return 0 if no phone was found.
289	*/	294	*/
290	int vfs_grab_phone(fs_handle_t handle)	295	int vfs_grab_phone(fs_handle_t handle)
291	{	296	{
292	/*	297	/*
293	* For now, we don't try to be very clever and very fast.	298	* For now, we don't try to be very clever and very fast.
294	* We simply lookup the phone in the fs_head list. We currently don't	299	* We simply lookup the phone in the fs_head list. We currently don't
295	* open any additional phones (even though that itself would be pretty	300	* open any additional phones (even though that itself would be pretty
296	* straightforward; housekeeping multiple open phones to a FS task would	301	* straightforward; housekeeping multiple open phones to a FS task would
297	* be more demanding). Instead, we simply take the respective	302	* be more demanding). Instead, we simply take the respective
298	* phone_futex and keep it until vfs_release_phone().	303	* phone_futex and keep it until vfs_release_phone().
299	*/	304	*/
300	futex_down(&fs_head_futex);	305	futex_down(&fs_head_futex);
301	link_t *cur;	306	link_t *cur;
302	fs_info_t *fs;	307	fs_info_t *fs;
303	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {	308	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
304	fs = list_get_instance(cur, fs_info_t, fs_link);	309	fs = list_get_instance(cur, fs_info_t, fs_link);
305	if (fs->fs_handle == handle) {	310	if (fs->fs_handle == handle) {
306	futex_up(&fs_head_futex);	311	futex_up(&fs_head_futex);
307	/*	312	/*
308	* For now, take the futex unconditionally.	313	* For now, take the futex unconditionally.
309	* Oh yeah, serialization rocks.	314	* Oh yeah, serialization rocks.
310	* It will be up'ed in vfs_release_phone().	315	* It will be up'ed in vfs_release_phone().
311	*/	316	*/
312	futex_down(&fs->phone_futex);	317	futex_down(&fs->phone_futex);
313	/*	318	/*
314	* Avoid deadlock with other fibrils in the same thread	319	* Avoid deadlock with other fibrils in the same thread
315	* by disabling fibril preemption.	320	* by disabling fibril preemption.
316	*/	321	*/
317	fibril_inc_sercount();	322	fibril_inc_sercount();
318	return fs->phone;	323	return fs->phone;
319	}	324	}
320	}	325	}
321	futex_up(&fs_head_futex);	326	futex_up(&fs_head_futex);
322	return 0;	327	return 0;
323	}	328	}
324		329
325	/** Tell VFS that the phone is in use for any request.	330	/** Tell VFS that the phone is in use for any request.
326	*	331	*
327	* @param phone Phone to FS task.	332	* @param phone Phone to FS task.
328	*/	333	*/
329	void vfs_release_phone(int phone)	334	void vfs_release_phone(int phone)
330	{	335	{
331	bool found = false;	336	bool found = false;
332		337
333	/*	338	/*
334	* Undo the fibril_inc_sercount() done in vfs_grab_phone().	339	* Undo the fibril_inc_sercount() done in vfs_grab_phone().
335	*/	340	*/
336	fibril_dec_sercount();	341	fibril_dec_sercount();
337		342
338	futex_down(&fs_head_futex);	343	futex_down(&fs_head_futex);
339	link_t *cur;	344	link_t *cur;
340	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {	345	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
341	fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);	346	fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
342	if (fs->phone == phone) {	347	if (fs->phone == phone) {
343	found = true;	348	found = true;
344	futex_up(&fs_head_futex);	349	futex_up(&fs_head_futex);
345	futex_up(&fs->phone_futex);	350	futex_up(&fs->phone_futex);
346	return;	351	return;
347	}	352	}
348	}	353	}
349	futex_up(&fs_head_futex);	354	futex_up(&fs_head_futex);
350		355
351	/*	356	/*
352	* Not good to get here.	357	* Not good to get here.
353	*/	358	*/
354	assert(found == true);	359	assert(found == true);
355	}	360	}
356		361
357	/** Convert file system name to its handle.	362	/** Convert file system name to its handle.
358	*	363	*
359	* @param name File system name.	364	* @param name File system name.
360	* @param lock If true, the function will down and up the	365	* @param lock If true, the function will down and up the
361	* fs_head_futex.	366	* fs_head_futex.
362	*	367	*
363	* @return File system handle or zero if file system not found.	368	* @return File system handle or zero if file system not found.
364	*/	369	*/
365	fs_handle_t fs_name_to_handle(char *name, bool lock)	370	fs_handle_t fs_name_to_handle(char *name, bool lock)
366	{	371	{
367	int handle = 0;	372	int handle = 0;
368		373
369	if (lock)	374	if (lock)
370	futex_down(&fs_head_futex);	375	futex_down(&fs_head_futex);
371	link_t *cur;	376	link_t *cur;
372	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {	377	for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
373	fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);	378	fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
374	if (strncmp(fs->vfs_info.name, name,	379	if (strncmp(fs->vfs_info.name, name,
375	sizeof(fs->vfs_info.name)) == 0) {	380	sizeof(fs->vfs_info.name)) == 0) {
376	handle = fs->fs_handle;	381	handle = fs->fs_handle;
377	break;	382	break;
378	}	383	}
379	}	384	}
380	if (lock)	385	if (lock)
381	futex_up(&fs_head_futex);	386	futex_up(&fs_head_futex);
382	return handle;	387	return handle;
383	}	388	}
384		389
385	/**	390	/**
386	* @}	391	* @}
387	*/	392	*/
388		393

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(root)/branches/dynload/uspace/srv/vfs/vfs_register.c – Rev 4341 → 4345