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2698 jermar 1
/*
2
 * Copyright (c) 2008 Jakub Jermar
3
 * All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
11
 * - Redistributions in binary form must reproduce the above copyright
12
 *   notice, this list of conditions and the following disclaimer in the
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
15
 *   derived from this software without specific prior written permission.
16
 *
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
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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
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
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 */
28
 
29
/** @addtogroup fs
30
 * @{
4345 svoboda 31
 */
2698 jermar 32
 
33
/**
4345 svoboda 34
 * @file vfs_register.c
2698 jermar 35
 * @brief
36
 */
37
 
38
#include <ipc/ipc.h>
39
#include <ipc/services.h>
40
#include <async.h>
41
#include <fibril.h>
42
#include <errno.h>
43
#include <stdio.h>
44
#include <stdlib.h>
45
#include <string.h>
46
#include <ctype.h>
47
#include <bool.h>
4691 svoboda 48
#include <fibril_sync.h>
49
#include <adt/list.h>
2698 jermar 50
#include <as.h>
51
#include <assert.h>
52
#include <atomic.h>
53
#include "vfs.h"
54
 
4691 svoboda 55
FIBRIL_CONDVAR_INITIALIZE(fs_head_cv);
56
FIBRIL_MUTEX_INITIALIZE(fs_head_lock);
57
LIST_INITIALIZE(fs_head);
2698 jermar 58
 
59
atomic_t fs_handle_next = {
60
    .count = 1
61
};
62
 
63
/** Verify the VFS info structure.
64
 *
65
 * @param info      Info structure to be verified.
66
 *
67
 * @return      Non-zero if the info structure is sane, zero otherwise.
68
 */
69
static bool vfs_info_sane(vfs_info_t *info)
70
{
71
    int i;
72
 
73
    /*
74
     * Check if the name is non-empty and is composed solely of ASCII
75
     * characters [a-z]+[a-z0-9_-]*.
76
     */
77
    if (!islower(info->name[0])) {
78
        dprintf("The name doesn't start with a lowercase character.\n");
79
        return false;
80
    }
81
    for (i = 1; i < FS_NAME_MAXLEN; i++) {
82
        if (!(islower(info->name[i]) || isdigit(info->name[i])) &&
83
            (info->name[i] != '-') && (info->name[i] != '_')) {
84
            if (info->name[i] == '\0') {
85
                break;
86
            } else {
87
                dprintf("The name contains illegal "
88
                    "characters.\n");
89
                return false;
90
            }
91
        }
92
    }
93
    /*
94
     * This check is not redundant. It ensures that the name is
95
     * NULL-terminated, even if FS_NAME_MAXLEN characters are used.
96
     */
97
    if (info->name[i] != '\0') {
98
        dprintf("The name is not properly NULL-terminated.\n");
99
        return false;
100
    }
101
 
102
    return true;
103
}
104
 
105
/** VFS_REGISTER protocol function.
106
 *
107
 * @param rid       Hash of the call with the request.
108
 * @param request   Call structure with the request.
109
 */
110
void vfs_register(ipc_callid_t rid, ipc_call_t *request)
111
{
112
    ipc_callid_t callid;
113
    ipc_call_t call;
114
    int rc;
115
    size_t size;
116
 
117
    dprintf("Processing VFS_REGISTER request received from %p.\n",
118
        request->in_phone_hash);
119
 
120
    /*
121
     * The first call has to be IPC_M_DATA_SEND in which we receive the
122
     * VFS info structure from the client FS.
123
     */
124
    if (!ipc_data_write_receive(&callid, &size)) {
125
        /*
126
         * The client doesn't obey the same protocol as we do.
127
         */
128
        dprintf("Receiving of VFS info failed.\n");
129
        ipc_answer_0(callid, EINVAL);
130
        ipc_answer_0(rid, EINVAL);
131
        return;
132
    }
133
 
134
    dprintf("VFS info received, size = %d\n", size);
135
 
136
    /*
137
     * We know the size of the VFS info structure. See if the client
138
     * understands this easy concept too.
139
     */
140
    if (size != sizeof(vfs_info_t)) {
141
        /*
142
         * The client is sending us something, which cannot be
143
         * the info structure.
144
         */
145
        dprintf("Received VFS info has bad size.\n");
146
        ipc_answer_0(callid, EINVAL);
147
        ipc_answer_0(rid, EINVAL);
148
        return;
149
    }
150
 
151
    /*
152
     * Allocate and initialize a buffer for the fs_info structure.
153
     */
154
    fs_info_t *fs_info;
155
    fs_info = (fs_info_t *) malloc(sizeof(fs_info_t));
156
    if (!fs_info) {
157
        dprintf("Could not allocate memory for FS info.\n");
158
        ipc_answer_0(callid, ENOMEM);
159
        ipc_answer_0(rid, ENOMEM);
160
        return;
161
    }
162
    link_initialize(&fs_info->fs_link);
4691 svoboda 163
    fibril_mutex_initialize(&fs_info->phone_lock);
2698 jermar 164
 
165
    rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size);
166
    if (rc != EOK) {
167
        dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n",
168
            rc);
169
        free(fs_info);
170
        ipc_answer_0(callid, rc);
171
        ipc_answer_0(rid, rc);
172
        return;
173
    }
174
 
175
    dprintf("VFS info delivered.\n");
176
 
177
    if (!vfs_info_sane(&fs_info->vfs_info)) {
178
        free(fs_info);
179
        ipc_answer_0(callid, EINVAL);
180
        ipc_answer_0(rid, EINVAL);
181
        return;
182
    }
183
 
4691 svoboda 184
    fibril_mutex_lock(&fs_head_lock);
2698 jermar 185
 
186
    /*
187
     * Check for duplicit registrations.
188
     */
189
    if (fs_name_to_handle(fs_info->vfs_info.name, false)) {
190
        /*
191
         * We already register a fs like this.
192
         */
193
        dprintf("FS is already registered.\n");
4691 svoboda 194
        fibril_mutex_unlock(&fs_head_lock);
2698 jermar 195
        free(fs_info);
196
        ipc_answer_0(callid, EEXISTS);
197
        ipc_answer_0(rid, EEXISTS);
198
        return;
199
    }
200
 
201
    /*
202
     * Add fs_info to the list of registered FS's.
203
     */
204
    dprintf("Inserting FS into the list of registered file systems.\n");
205
    list_append(&fs_info->fs_link, &fs_head);
2768 jermar 206
 
2698 jermar 207
    /*
208
     * Now we want the client to send us the IPC_M_CONNECT_TO_ME call so
209
     * that a callback connection is created and we have a phone through
210
     * which to forward VFS requests to it.
211
     */
212
    callid = async_get_call(&call);
213
    if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) {
214
        dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
215
        list_remove(&fs_info->fs_link);
4691 svoboda 216
        fibril_mutex_unlock(&fs_head_lock);
2698 jermar 217
        free(fs_info);
218
        ipc_answer_0(callid, EINVAL);
219
        ipc_answer_0(rid, EINVAL);
220
        return;
221
    }
222
    fs_info->phone = IPC_GET_ARG5(call);
223
    ipc_answer_0(callid, EOK);
224
 
225
    dprintf("Callback connection to FS created.\n");
226
 
227
    /*
228
     * The client will want us to send him the address space area with PLB.
229
     */
230
 
231
    if (!ipc_share_in_receive(&callid, &size)) {
232
        dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
233
        list_remove(&fs_info->fs_link);
4691 svoboda 234
        fibril_mutex_unlock(&fs_head_lock);
2698 jermar 235
        ipc_hangup(fs_info->phone);
236
        free(fs_info);
237
        ipc_answer_0(callid, EINVAL);
238
        ipc_answer_0(rid, EINVAL);
239
        return;
240
    }
241
 
242
    /*
243
     * We can only send the client address space area PLB_SIZE bytes long.
244
     */
245
    if (size != PLB_SIZE) {
246
        dprintf("Client suggests wrong size of PFB, size = %d\n", size);
247
        list_remove(&fs_info->fs_link);
4691 svoboda 248
        fibril_mutex_unlock(&fs_head_lock);
2698 jermar 249
        ipc_hangup(fs_info->phone);
250
        free(fs_info);
251
        ipc_answer_0(callid, EINVAL);
252
        ipc_answer_0(rid, EINVAL);
253
        return;
254
    }
255
 
256
    /*
257
     * Commit to read-only sharing the PLB with the client.
258
     */
259
    (void) ipc_share_in_finalize(callid, plb,
260
        AS_AREA_READ | AS_AREA_CACHEABLE);
261
 
262
    dprintf("Sharing PLB.\n");
263
 
264
    /*
265
     * That was it. The FS has been registered.
266
     * In reply to the VFS_REGISTER request, we assign the client file
267
     * system a global file system handle.
268
     */
2770 jermar 269
    fs_info->fs_handle = (fs_handle_t) atomic_postinc(&fs_handle_next);
2698 jermar 270
    ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle);
271
 
4691 svoboda 272
    fibril_condvar_broadcast(&fs_head_cv);
273
    fibril_mutex_unlock(&fs_head_lock);
2698 jermar 274
 
275
    dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n",
276
        FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle);
277
}
278
 
279
/** For a given file system handle, implement policy for allocating a phone.
280
 *
281
 * @param handle    File system handle.
282
 *
283
 * @return      Phone over which a multi-call request can be safely
284
 *          sent. Return 0 if no phone was found.
285
 */
2770 jermar 286
int vfs_grab_phone(fs_handle_t handle)
2698 jermar 287
{
4691 svoboda 288
    int phone;
289
 
2698 jermar 290
    /*
4691 svoboda 291
     * For now, we don't try to be very clever and very fast.  We simply
292
     * lookup the phone in the fs_head list and duplicate it.  The duplicate
293
     * phone will be returned to the client and the client will use it for
294
     * communication.  In the future, we should cache the connections so
295
     * that they do not have to be reestablished over and over again.
2698 jermar 296
     */
4691 svoboda 297
    fibril_mutex_lock(&fs_head_lock);
2698 jermar 298
    link_t *cur;
299
    fs_info_t *fs;
300
    for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
301
        fs = list_get_instance(cur, fs_info_t, fs_link);
302
        if (fs->fs_handle == handle) {
4691 svoboda 303
            fibril_mutex_unlock(&fs_head_lock);
304
            fibril_mutex_lock(&fs->phone_lock);
305
            phone = ipc_connect_me_to(fs->phone, 0, 0, 0);
306
            fibril_mutex_unlock(&fs->phone_lock);
307
 
308
            assert(phone > 0);
309
            return phone;
2698 jermar 310
        }
311
    }
4691 svoboda 312
    fibril_mutex_unlock(&fs_head_lock);
2698 jermar 313
    return 0;
314
}
315
 
4691 svoboda 316
/** Tell VFS that the phone is not needed anymore.
2698 jermar 317
 *
318
 * @param phone     Phone to FS task.
319
 */
320
void vfs_release_phone(int phone)
321
{
4691 svoboda 322
    /* TODO: implement connection caching */
323
    ipc_hangup(phone);
2698 jermar 324
}
325
 
326
/** Convert file system name to its handle.
327
 *
328
 * @param name      File system name.
4691 svoboda 329
 * @param lock      If true, the function will lock and unlock the
330
 *          fs_head_lock.
2698 jermar 331
 *
332
 * @return      File system handle or zero if file system not found.
333
 */
2770 jermar 334
fs_handle_t fs_name_to_handle(char *name, bool lock)
2698 jermar 335
{
336
    int handle = 0;
337
 
338
    if (lock)
4691 svoboda 339
        fibril_mutex_lock(&fs_head_lock);
2698 jermar 340
    link_t *cur;
341
    for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
342
        fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
4348 svoboda 343
        if (str_cmp(fs->vfs_info.name, name) == 0) {
2698 jermar 344
            handle = fs->fs_handle;
345
            break;
346
        }
347
    }
348
    if (lock)
4691 svoboda 349
        fibril_mutex_unlock(&fs_head_lock);
2698 jermar 350
    return handle;
351
}
352
 
353
/**
354
 * @}
355
 */