source: mainline/uspace/lib/libfs/libfs.c@ 854c564

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 854c564 was 83937ccd, checked in by Jakub Jermar <jakub@…>, 16 years ago

Rudimentary support for non-root mounts.
  • Property mode set to 100644
File size: 11.0 KB
Line 
1/*
2 * Copyright (c) 2009 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 libfs
30 * @{
31 */
32/**
33 * @file
34 * Glue code which is commonod to all FS implementations.
35 */
36
37#include "libfs.h"
38#include "../../srv/vfs/vfs.h"
39#include <errno.h>
40#include <async.h>
41#include <ipc/ipc.h>
42#include <as.h>
43#include <assert.h>
44#include <dirent.h>
45
46/** Register file system server.
47 *
48 * This function abstracts away the tedious registration protocol from
49 * file system implementations and lets them to reuse this registration glue
50 * code.
51 *
52 * @param vfs_phone Open phone for communication with VFS.
53 * @param reg File system registration structure. It will be
54 * initialized by this function.
55 * @param info VFS info structure supplied by the file system
56 * implementation.
57 * @param conn Connection fibril for handling all calls originating in
58 * VFS.
59 *
60 * @return EOK on success or a non-zero error code on errror.
61 */
62int fs_register(int vfs_phone, fs_reg_t *reg, vfs_info_t *info,
63 async_client_conn_t conn)
64{
65 /*
66 * Tell VFS that we are here and want to get registered.
67 * We use the async framework because VFS will answer the request
68 * out-of-order, when it knows that the operation succeeded or failed.
69 */
70 ipc_call_t answer;
71 aid_t req = async_send_0(vfs_phone, VFS_REGISTER, &answer);
72
73 /*
74 * Send our VFS info structure to VFS.
75 */
76 int rc = ipc_data_write_start(vfs_phone, info, sizeof(*info));
77 if (rc != EOK) {
78 async_wait_for(req, NULL);
79 return rc;
80 }
81
82 /*
83 * Ask VFS for callback connection.
84 */
85 ipc_connect_to_me(vfs_phone, 0, 0, 0, &reg->vfs_phonehash);
86
87 /*
88 * Allocate piece of address space for PLB.
89 */
90 reg->plb_ro = as_get_mappable_page(PLB_SIZE);
91 if (!reg->plb_ro) {
92 async_wait_for(req, NULL);
93 return ENOMEM;
94 }
95
96 /*
97 * Request sharing the Path Lookup Buffer with VFS.
98 */
99 rc = ipc_share_in_start_0_0(vfs_phone, reg->plb_ro, PLB_SIZE);
100 if (rc) {
101 async_wait_for(req, NULL);
102 return rc;
103 }
104
105 /*
106 * Pick up the answer for the request to the VFS_REQUEST call.
107 */
108 async_wait_for(req, NULL);
109 reg->fs_handle = (int) IPC_GET_ARG1(answer);
110
111 /*
112 * Create a connection fibril to handle the callback connection.
113 */
114 async_new_connection(reg->vfs_phonehash, 0, NULL, conn);
115
116 /*
117 * Tell the async framework that other connections are to be handled by
118 * the same connection fibril as well.
119 */
120 async_set_client_connection(conn);
121
122 return IPC_GET_RETVAL(answer);
123}
124
125void fs_node_initialize(fs_node_t *fn)
126{
127 memset(fn, 0, sizeof(fs_node_t));
128}
129
130void libfs_mount(libfs_ops_t *ops, ipc_callid_t rid, ipc_call_t *request)
131{
132 dev_handle_t mp_dev_handle = (dev_handle_t)IPC_GET_ARG1(*request);
133 fs_index_t mp_fs_index = (fs_index_t)IPC_GET_ARG2(*request);
134 fs_handle_t mr_fs_handle = (fs_handle_t)IPC_GET_ARG3(*request);
135 dev_handle_t mr_dev_handle = (dev_handle_t)IPC_GET_ARG4(*request);
136 int res;
137 ipcarg_t rc;
138
139 ipc_call_t call;
140 ipc_callid_t callid;
141
142 /* accept the phone */
143 callid = async_get_call(&call);
144 int mountee_phone = (int)IPC_GET_ARG1(call);
145 if ((IPC_GET_METHOD(call) != IPC_M_CONNECTION_CLONE) ||
146 mountee_phone < 0) {
147 ipc_answer_0(callid, EINVAL);
148 ipc_answer_0(rid, EINVAL);
149 return;
150 }
151 ipc_answer_0(callid, EOK); /* acknowledge the mountee_phone */
152
153 res = ipc_data_write_receive(&callid, NULL);
154 if (!res) {
155 ipc_hangup(mountee_phone);
156 ipc_answer_0(callid, EINVAL);
157 ipc_answer_0(rid, EINVAL);
158 return;
159 }
160
161 fs_node_t *fn = ops->node_get(mp_dev_handle, mp_fs_index);
162 if (!fn) {
163 ipc_hangup(mountee_phone);
164 ipc_answer_0(callid, ENOENT);
165 ipc_answer_0(rid, ENOENT);
166 return;
167 }
168
169 if (fn->mp_data.mp_active) {
170 ipc_hangup(mountee_phone);
171 ops->node_put(fn);
172 ipc_answer_0(callid, EBUSY);
173 ipc_answer_0(rid, EBUSY);
174 return;
175 }
176
177 rc = async_req_0_0(mountee_phone, IPC_M_CONNECT_ME);
178 if (rc != 0) {
179 ipc_hangup(mountee_phone);
180 ops->node_put(fn);
181 ipc_answer_0(callid, rc);
182 ipc_answer_0(rid, rc);
183 return;
184 }
185
186 ipc_call_t answer;
187 aid_t msg = async_send_1(mountee_phone, VFS_MOUNTED, mr_dev_handle,
188 &answer);
189 ipc_forward_fast(callid, mountee_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME);
190 async_wait_for(msg, &rc);
191
192 if (rc == EOK) {
193 fn->mp_data.mp_active = true;
194 fn->mp_data.fs_handle = mr_fs_handle;
195 fn->mp_data.dev_handle = mr_dev_handle;
196 fn->mp_data.phone = mountee_phone;
197 }
198 /*
199 * Do not release the FS node so that it stays in memory.
200 */
201 ipc_answer_0(rid, rc);
202}
203
204/** Lookup VFS triplet by name in the file system name space.
205 *
206 * The path passed in the PLB must be in the canonical file system path format
207 * as returned by the canonify() function.
208 *
209 * @param ops libfs operations structure with function pointers to
210 * file system implementation
211 * @param fs_handle File system handle of the file system where to perform
212 * the lookup.
213 * @param rid Request ID of the VFS_LOOKUP request.
214 * @param request VFS_LOOKUP request data itself.
215 */
216void libfs_lookup(libfs_ops_t *ops, fs_handle_t fs_handle, ipc_callid_t rid,
217 ipc_call_t *request)
218{
219 unsigned first = IPC_GET_ARG1(*request);
220 unsigned last = IPC_GET_ARG2(*request);
221 unsigned next = first;
222 dev_handle_t dev_handle = IPC_GET_ARG3(*request);
223 int lflag = IPC_GET_ARG4(*request);
224 fs_index_t index = IPC_GET_ARG5(*request); /* when L_LINK specified */
225 char component[NAME_MAX + 1];
226 int len;
227
228 if (last < next)
229 last += PLB_SIZE;
230
231 fs_node_t *par = NULL;
232 fs_node_t *cur = ops->root_get(dev_handle);
233 fs_node_t *tmp = NULL;
234
235 if (cur->mp_data.mp_active) {
236 ipc_forward_slow(rid, cur->mp_data.phone, VFS_LOOKUP,
237 next, last, cur->mp_data.dev_handle, lflag, index,
238 IPC_FF_ROUTE_FROM_ME);
239 ops->node_put(cur);
240 return;
241 }
242
243 if (ops->plb_get_char(next) == '/')
244 next++; /* eat slash */
245
246 while (next <= last && ops->has_children(cur)) {
247 /* collect the component */
248 len = 0;
249 while ((next <= last) && (ops->plb_get_char(next) != '/')) {
250 if (len + 1 == NAME_MAX) {
251 /* component length overflow */
252 ipc_answer_0(rid, ENAMETOOLONG);
253 goto out;
254 }
255 component[len++] = ops->plb_get_char(next);
256 next++; /* process next character */
257 }
258
259 assert(len);
260 component[len] = '\0';
261 next++; /* eat slash */
262
263 /* match the component */
264 tmp = ops->match(cur, component);
265 if (tmp && tmp->mp_data.mp_active) {
266 if (next > last)
267 next = last = first;
268 else
269 next--;
270
271 ipc_forward_slow(rid, tmp->mp_data.phone, VFS_LOOKUP,
272 next, last, tmp->mp_data.dev_handle, lflag, index,
273 IPC_FF_ROUTE_FROM_ME);
274 ops->node_put(cur);
275 ops->node_put(tmp);
276 if (par)
277 ops->node_put(par);
278 return;
279 }
280
281 /* handle miss: match amongst siblings */
282 if (!tmp) {
283 if (next <= last) {
284 /* there are unprocessed components */
285 ipc_answer_0(rid, ENOENT);
286 goto out;
287 }
288 /* miss in the last component */
289 if (lflag & (L_CREATE | L_LINK)) {
290 /* request to create a new link */
291 if (!ops->is_directory(cur)) {
292 ipc_answer_0(rid, ENOTDIR);
293 goto out;
294 }
295 fs_node_t *fn;
296 if (lflag & L_CREATE)
297 fn = ops->create(dev_handle, lflag);
298 else
299 fn = ops->node_get(dev_handle,
300 index);
301 if (fn) {
302 int rc;
303
304 rc = ops->link(cur, fn, component);
305 if (rc != EOK) {
306 if (lflag & L_CREATE) {
307 (void)ops->destroy(fn);
308 }
309 ipc_answer_0(rid, rc);
310 } else {
311 ipc_answer_5(rid, EOK,
312 fs_handle, dev_handle,
313 ops->index_get(fn),
314 ops->size_get(fn),
315 ops->lnkcnt_get(fn));
316 ops->node_put(fn);
317 }
318 } else {
319 ipc_answer_0(rid, ENOSPC);
320 }
321 goto out;
322 }
323 ipc_answer_0(rid, ENOENT);
324 goto out;
325 }
326
327 if (par)
328 ops->node_put(par);
329
330 /* descend one level */
331 par = cur;
332 cur = tmp;
333 tmp = NULL;
334 }
335
336 /* handle miss: excessive components */
337 if (next <= last && !ops->has_children(cur)) {
338 if (lflag & (L_CREATE | L_LINK)) {
339 if (!ops->is_directory(cur)) {
340 ipc_answer_0(rid, ENOTDIR);
341 goto out;
342 }
343
344 /* collect next component */
345 len = 0;
346 while (next <= last) {
347 if (ops->plb_get_char(next) == '/') {
348 /* more than one component */
349 ipc_answer_0(rid, ENOENT);
350 goto out;
351 }
352 if (len + 1 == NAME_MAX) {
353 /* component length overflow */
354 ipc_answer_0(rid, ENAMETOOLONG);
355 goto out;
356 }
357 component[len++] = ops->plb_get_char(next);
358 next++; /* process next character */
359 }
360 assert(len);
361 component[len] = '\0';
362
363 fs_node_t *fn;
364 if (lflag & L_CREATE)
365 fn = ops->create(dev_handle, lflag);
366 else
367 fn = ops->node_get(dev_handle, index);
368 if (fn) {
369 int rc;
370
371 rc = ops->link(cur, fn, component);
372 if (rc != EOK) {
373 if (lflag & L_CREATE)
374 (void)ops->destroy(fn);
375 ipc_answer_0(rid, rc);
376 } else {
377 ipc_answer_5(rid, EOK,
378 fs_handle, dev_handle,
379 ops->index_get(fn),
380 ops->size_get(fn),
381 ops->lnkcnt_get(fn));
382 ops->node_put(fn);
383 }
384 } else {
385 ipc_answer_0(rid, ENOSPC);
386 }
387 goto out;
388 }
389 ipc_answer_0(rid, ENOENT);
390 goto out;
391 }
392
393 /* handle hit */
394 if (lflag & L_UNLINK) {
395 unsigned old_lnkcnt = ops->lnkcnt_get(cur);
396 int res = ops->unlink(par, cur, component);
397 ipc_answer_5(rid, (ipcarg_t)res, fs_handle, dev_handle,
398 ops->index_get(cur), ops->size_get(cur), old_lnkcnt);
399 goto out;
400 }
401 if (((lflag & (L_CREATE | L_EXCLUSIVE)) == (L_CREATE | L_EXCLUSIVE)) ||
402 (lflag & L_LINK)) {
403 ipc_answer_0(rid, EEXIST);
404 goto out;
405 }
406 if ((lflag & L_FILE) && (ops->is_directory(cur))) {
407 ipc_answer_0(rid, EISDIR);
408 goto out;
409 }
410 if ((lflag & L_DIRECTORY) && (ops->is_file(cur))) {
411 ipc_answer_0(rid, ENOTDIR);
412 goto out;
413 }
414
415 ipc_answer_5(rid, EOK, fs_handle, dev_handle, ops->index_get(cur),
416 ops->size_get(cur), ops->lnkcnt_get(cur));
417
418out:
419 if (par)
420 ops->node_put(par);
421 if (cur)
422 ops->node_put(cur);
423 if (tmp)
424 ops->node_put(tmp);
425}
426
427/** @}
428 */
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