Rev 2731 | Rev 2770 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
---|---|---|---|
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 | * @{ |
||
31 | */ |
||
32 | |||
33 | /** |
||
34 | * @file vfs_register.c |
||
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> |
||
48 | #include <futex.h> |
||
49 | #include <libadt/list.h> |
||
50 | #include <as.h> |
||
51 | #include <assert.h> |
||
52 | #include <atomic.h> |
||
53 | #include "vfs.h" |
||
54 | |||
55 | atomic_t fs_head_futex = FUTEX_INITIALIZER; |
||
56 | link_t fs_head; |
||
57 | |||
58 | atomic_t fs_handle_next = { |
||
59 | .count = 1 |
||
60 | }; |
||
61 | |||
62 | /** Verify the VFS info structure. |
||
63 | * |
||
64 | * @param info Info structure to be verified. |
||
65 | * |
||
66 | * @return Non-zero if the info structure is sane, zero otherwise. |
||
67 | */ |
||
68 | static bool vfs_info_sane(vfs_info_t *info) |
||
69 | { |
||
70 | int i; |
||
71 | |||
72 | /* |
||
73 | * Check if the name is non-empty and is composed solely of ASCII |
||
74 | * characters [a-z]+[a-z0-9_-]*. |
||
75 | */ |
||
76 | if (!islower(info->name[0])) { |
||
77 | dprintf("The name doesn't start with a lowercase character.\n"); |
||
78 | return false; |
||
79 | } |
||
80 | for (i = 1; i < FS_NAME_MAXLEN; i++) { |
||
81 | if (!(islower(info->name[i]) || isdigit(info->name[i])) && |
||
82 | (info->name[i] != '-') && (info->name[i] != '_')) { |
||
83 | if (info->name[i] == '\0') { |
||
84 | break; |
||
85 | } else { |
||
86 | dprintf("The name contains illegal " |
||
87 | "characters.\n"); |
||
88 | return false; |
||
89 | } |
||
90 | } |
||
91 | } |
||
92 | /* |
||
93 | * This check is not redundant. It ensures that the name is |
||
94 | * NULL-terminated, even if FS_NAME_MAXLEN characters are used. |
||
95 | */ |
||
96 | if (info->name[i] != '\0') { |
||
97 | dprintf("The name is not properly NULL-terminated.\n"); |
||
98 | return false; |
||
99 | } |
||
100 | |||
101 | |||
102 | /* |
||
103 | * Check if the FS implements mandatory VFS operations. |
||
104 | */ |
||
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"); |
||
107 | return false; |
||
108 | } |
||
109 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_READ)] != VFS_OP_DEFINED) { |
||
110 | dprintf("Operation VFS_READ not defined by the client.\n"); |
||
111 | return false; |
||
112 | } |
||
113 | |||
114 | /* |
||
115 | * Check if each operation is either not defined, defined or default. |
||
116 | */ |
||
117 | for (i = VFS_FIRST; i < VFS_LAST_CLNT; i++) { |
||
118 | if ((info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_NULL) && |
||
119 | (info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFAULT) && |
||
120 | (info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFINED)) { |
||
121 | dprintf("Operation info not understood.\n"); |
||
122 | return false; |
||
123 | } |
||
124 | } |
||
125 | return true; |
||
126 | } |
||
127 | |||
128 | /** VFS_REGISTER protocol function. |
||
129 | * |
||
130 | * @param rid Hash of the call with the request. |
||
131 | * @param request Call structure with the request. |
||
132 | */ |
||
133 | void vfs_register(ipc_callid_t rid, ipc_call_t *request) |
||
134 | { |
||
135 | ipc_callid_t callid; |
||
136 | ipc_call_t call; |
||
137 | int rc; |
||
138 | size_t size; |
||
139 | |||
140 | dprintf("Processing VFS_REGISTER request received from %p.\n", |
||
141 | request->in_phone_hash); |
||
142 | |||
143 | /* |
||
144 | * The first call has to be IPC_M_DATA_SEND in which we receive the |
||
145 | * VFS info structure from the client FS. |
||
146 | */ |
||
147 | if (!ipc_data_write_receive(&callid, &size)) { |
||
148 | /* |
||
149 | * The client doesn't obey the same protocol as we do. |
||
150 | */ |
||
151 | dprintf("Receiving of VFS info failed.\n"); |
||
152 | ipc_answer_0(callid, EINVAL); |
||
153 | ipc_answer_0(rid, EINVAL); |
||
154 | return; |
||
155 | } |
||
156 | |||
157 | dprintf("VFS info received, size = %d\n", size); |
||
158 | |||
159 | /* |
||
160 | * We know the size of the VFS info structure. See if the client |
||
161 | * understands this easy concept too. |
||
162 | */ |
||
163 | if (size != sizeof(vfs_info_t)) { |
||
164 | /* |
||
165 | * The client is sending us something, which cannot be |
||
166 | * the info structure. |
||
167 | */ |
||
168 | dprintf("Received VFS info has bad size.\n"); |
||
169 | ipc_answer_0(callid, EINVAL); |
||
170 | ipc_answer_0(rid, EINVAL); |
||
171 | return; |
||
172 | } |
||
173 | |||
174 | /* |
||
175 | * Allocate and initialize a buffer for the fs_info structure. |
||
176 | */ |
||
177 | fs_info_t *fs_info; |
||
178 | fs_info = (fs_info_t *) malloc(sizeof(fs_info_t)); |
||
179 | if (!fs_info) { |
||
180 | dprintf("Could not allocate memory for FS info.\n"); |
||
181 | ipc_answer_0(callid, ENOMEM); |
||
182 | ipc_answer_0(rid, ENOMEM); |
||
183 | return; |
||
184 | } |
||
185 | link_initialize(&fs_info->fs_link); |
||
186 | futex_initialize(&fs_info->phone_futex, 1); |
||
187 | |||
188 | rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size); |
||
189 | if (rc != EOK) { |
||
190 | dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n", |
||
191 | rc); |
||
192 | free(fs_info); |
||
193 | ipc_answer_0(callid, rc); |
||
194 | ipc_answer_0(rid, rc); |
||
195 | return; |
||
196 | } |
||
197 | |||
198 | dprintf("VFS info delivered.\n"); |
||
199 | |||
200 | if (!vfs_info_sane(&fs_info->vfs_info)) { |
||
201 | free(fs_info); |
||
202 | ipc_answer_0(callid, EINVAL); |
||
203 | ipc_answer_0(rid, EINVAL); |
||
204 | return; |
||
205 | } |
||
206 | |||
207 | futex_down(&fs_head_futex); |
||
2768 | jermar | 208 | fibril_inc_sercount(); |
2698 | jermar | 209 | |
210 | /* |
||
211 | * Check for duplicit registrations. |
||
212 | */ |
||
213 | if (fs_name_to_handle(fs_info->vfs_info.name, false)) { |
||
214 | /* |
||
215 | * We already register a fs like this. |
||
216 | */ |
||
217 | dprintf("FS is already registered.\n"); |
||
2768 | jermar | 218 | fibril_dec_sercount(); |
2698 | jermar | 219 | futex_up(&fs_head_futex); |
220 | free(fs_info); |
||
221 | ipc_answer_0(callid, EEXISTS); |
||
222 | ipc_answer_0(rid, EEXISTS); |
||
223 | return; |
||
224 | } |
||
225 | |||
226 | /* |
||
227 | * Add fs_info to the list of registered FS's. |
||
228 | */ |
||
229 | dprintf("Inserting FS into the list of registered file systems.\n"); |
||
230 | list_append(&fs_info->fs_link, &fs_head); |
||
2768 | jermar | 231 | |
2698 | jermar | 232 | /* |
233 | * Now we want the client to send us the IPC_M_CONNECT_TO_ME call so |
||
234 | * that a callback connection is created and we have a phone through |
||
235 | * which to forward VFS requests to it. |
||
236 | */ |
||
237 | callid = async_get_call(&call); |
||
238 | if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) { |
||
239 | dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call)); |
||
240 | list_remove(&fs_info->fs_link); |
||
2768 | jermar | 241 | fibril_dec_sercount(); |
2698 | jermar | 242 | futex_up(&fs_head_futex); |
243 | free(fs_info); |
||
244 | ipc_answer_0(callid, EINVAL); |
||
245 | ipc_answer_0(rid, EINVAL); |
||
246 | return; |
||
247 | } |
||
248 | fs_info->phone = IPC_GET_ARG5(call); |
||
249 | ipc_answer_0(callid, EOK); |
||
250 | |||
251 | dprintf("Callback connection to FS created.\n"); |
||
252 | |||
253 | /* |
||
254 | * The client will want us to send him the address space area with PLB. |
||
255 | */ |
||
256 | |||
257 | if (!ipc_share_in_receive(&callid, &size)) { |
||
258 | dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call)); |
||
259 | list_remove(&fs_info->fs_link); |
||
2768 | jermar | 260 | fibril_dec_sercount(); |
2698 | jermar | 261 | futex_up(&fs_head_futex); |
262 | ipc_hangup(fs_info->phone); |
||
263 | free(fs_info); |
||
264 | ipc_answer_0(callid, EINVAL); |
||
265 | ipc_answer_0(rid, EINVAL); |
||
266 | return; |
||
267 | } |
||
268 | |||
269 | /* |
||
270 | * We can only send the client address space area PLB_SIZE bytes long. |
||
271 | */ |
||
272 | if (size != PLB_SIZE) { |
||
273 | dprintf("Client suggests wrong size of PFB, size = %d\n", size); |
||
274 | list_remove(&fs_info->fs_link); |
||
2768 | jermar | 275 | fibril_dec_sercount(); |
2698 | jermar | 276 | futex_up(&fs_head_futex); |
277 | ipc_hangup(fs_info->phone); |
||
278 | free(fs_info); |
||
279 | ipc_answer_0(callid, EINVAL); |
||
280 | ipc_answer_0(rid, EINVAL); |
||
281 | return; |
||
282 | } |
||
283 | |||
284 | /* |
||
285 | * Commit to read-only sharing the PLB with the client. |
||
286 | */ |
||
287 | (void) ipc_share_in_finalize(callid, plb, |
||
288 | AS_AREA_READ | AS_AREA_CACHEABLE); |
||
289 | |||
290 | dprintf("Sharing PLB.\n"); |
||
291 | |||
292 | /* |
||
293 | * That was it. The FS has been registered. |
||
294 | * In reply to the VFS_REGISTER request, we assign the client file |
||
295 | * system a global file system handle. |
||
296 | */ |
||
297 | fs_info->fs_handle = (int) atomic_postinc(&fs_handle_next); |
||
298 | ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle); |
||
299 | |||
2768 | jermar | 300 | fibril_dec_sercount(); |
2698 | jermar | 301 | futex_up(&fs_head_futex); |
302 | |||
303 | dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n", |
||
304 | FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle); |
||
305 | } |
||
306 | |||
307 | /** For a given file system handle, implement policy for allocating a phone. |
||
308 | * |
||
309 | * @param handle File system handle. |
||
310 | * |
||
311 | * @return Phone over which a multi-call request can be safely |
||
312 | * sent. Return 0 if no phone was found. |
||
313 | */ |
||
314 | int vfs_grab_phone(int handle) |
||
315 | { |
||
316 | /* |
||
317 | * For now, we don't try to be very clever and very fast. |
||
318 | * We simply lookup the phone in the fs_head list. We currently don't |
||
319 | * open any additional phones (even though that itself would be pretty |
||
320 | * straightforward; housekeeping multiple open phones to a FS task would |
||
321 | * be more demanding). Instead, we simply take the respective |
||
322 | * phone_futex and keep it until vfs_release_phone(). |
||
323 | */ |
||
324 | futex_down(&fs_head_futex); |
||
325 | link_t *cur; |
||
326 | fs_info_t *fs; |
||
327 | for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
||
328 | fs = list_get_instance(cur, fs_info_t, fs_link); |
||
329 | if (fs->fs_handle == handle) { |
||
330 | futex_up(&fs_head_futex); |
||
331 | /* |
||
332 | * For now, take the futex unconditionally. |
||
333 | * Oh yeah, serialization rocks. |
||
334 | * It will be up'ed in vfs_release_phone(). |
||
335 | */ |
||
336 | futex_down(&fs->phone_futex); |
||
337 | /* |
||
338 | * Avoid deadlock with other fibrils in the same thread |
||
339 | * by disabling fibril preemption. |
||
340 | */ |
||
341 | fibril_inc_sercount(); |
||
342 | return fs->phone; |
||
343 | } |
||
344 | } |
||
345 | futex_up(&fs_head_futex); |
||
346 | return 0; |
||
347 | } |
||
348 | |||
349 | /** Tell VFS that the phone is in use for any request. |
||
350 | * |
||
351 | * @param phone Phone to FS task. |
||
352 | */ |
||
353 | void vfs_release_phone(int phone) |
||
354 | { |
||
355 | bool found = false; |
||
356 | |||
357 | /* |
||
358 | * Undo the fibril_inc_sercount() done in vfs_grab_phone(). |
||
359 | */ |
||
360 | fibril_dec_sercount(); |
||
361 | |||
362 | futex_down(&fs_head_futex); |
||
363 | link_t *cur; |
||
364 | for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
||
365 | fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link); |
||
366 | if (fs->phone == phone) { |
||
367 | found = true; |
||
368 | futex_up(&fs_head_futex); |
||
369 | futex_up(&fs->phone_futex); |
||
370 | return; |
||
371 | } |
||
372 | } |
||
373 | futex_up(&fs_head_futex); |
||
374 | |||
375 | /* |
||
376 | * Not good to get here. |
||
377 | */ |
||
378 | assert(found == true); |
||
379 | } |
||
380 | |||
381 | /** Convert file system name to its handle. |
||
382 | * |
||
383 | * @param name File system name. |
||
384 | * @param lock If true, the function will down and up the |
||
385 | * fs_head_futex. |
||
386 | * |
||
387 | * @return File system handle or zero if file system not found. |
||
388 | */ |
||
389 | int fs_name_to_handle(char *name, bool lock) |
||
390 | { |
||
391 | int handle = 0; |
||
392 | |||
393 | if (lock) |
||
394 | futex_down(&fs_head_futex); |
||
395 | link_t *cur; |
||
396 | for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
||
397 | fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link); |
||
398 | if (strncmp(fs->vfs_info.name, name, |
||
399 | sizeof(fs->vfs_info.name)) == 0) { |
||
400 | handle = fs->fs_handle; |
||
401 | break; |
||
402 | } |
||
403 | } |
||
404 | if (lock) |
||
405 | futex_up(&fs_head_futex); |
||
406 | return handle; |
||
407 | } |
||
408 | |||
409 | /** |
||
410 | * @} |
||
411 | */ |