source: mainline/uspace/lib/libfs/libfs.c@ 1a60feeb

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 1a60feeb was 34f62f8, checked in by Jakub Jermar <jakub@…>, 17 years ago

Revert libfs node_get() API to a model without the parent node pointer
argument.
  • Property mode set to 100644
File size: 8.7 KB
Line 
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 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
125/** Lookup VFS triplet by name in the file system name space.
126 *
127 * The path passed in the PLB must be in the canonical file system path format
128 * as returned by the canonify() function.
129 *
130 * @param ops libfs operations structure with function pointers to
131 * file system implementation
132 * @param fs_handle File system handle of the file system where to perform
133 * the lookup.
134 * @param rid Request ID of the VFS_LOOKUP request.
135 * @param request VFS_LOOKUP request data itself.
136 */
137void libfs_lookup(libfs_ops_t *ops, fs_handle_t fs_handle, ipc_callid_t rid,
138 ipc_call_t *request)
139{
140 unsigned next = IPC_GET_ARG1(*request);
141 unsigned last = IPC_GET_ARG2(*request);
142 dev_handle_t dev_handle = IPC_GET_ARG3(*request);
143 int lflag = IPC_GET_ARG4(*request);
144 fs_index_t index = IPC_GET_ARG5(*request); /* when L_LINK specified */
145 char component[NAME_MAX + 1];
146 int len;
147
148 if (last < next)
149 last += PLB_SIZE;
150
151 void *par = NULL;
152 void *cur = ops->root_get(dev_handle);
153 void *tmp = NULL;
154
155 if (ops->plb_get_char(next) == '/')
156 next++; /* eat slash */
157
158 while (ops->has_children(cur) && next <= last) {
159 /* collect the component */
160 len = 0;
161 while ((ops->plb_get_char(next) != '/') && (next <= last)) {
162 if (len + 1 == NAME_MAX) {
163 /* comopnent length overflow */
164 ipc_answer_0(rid, ENAMETOOLONG);
165 goto out;
166 }
167 component[len++] = ops->plb_get_char(next);
168 next++; /* process next character */
169 }
170
171 assert(len);
172 component[len] = '\0';
173 next++; /* eat slash */
174
175 /* match the component */
176 tmp = ops->match(cur, component);
177
178 /* handle miss: match amongst siblings */
179 if (!tmp) {
180 if (next <= last) {
181 /* there are unprocessed components */
182 ipc_answer_0(rid, ENOENT);
183 goto out;
184 }
185 /* miss in the last component */
186 if (lflag & (L_CREATE | L_LINK)) {
187 /* request to create a new link */
188 if (!ops->is_directory(cur)) {
189 ipc_answer_0(rid, ENOTDIR);
190 goto out;
191 }
192 void *nodep;
193 if (lflag & L_CREATE)
194 nodep = ops->create(lflag);
195 else
196 nodep = ops->node_get(dev_handle,
197 index);
198 if (nodep) {
199 if (!ops->link(cur, nodep, component)) {
200 if (lflag & L_CREATE)
201 (void)ops->destroy(nodep);
202 ipc_answer_0(rid, ENOSPC);
203 } else {
204 ipc_answer_5(rid, EOK,
205 fs_handle, dev_handle,
206 ops->index_get(nodep),
207 ops->size_get(nodep),
208 ops->lnkcnt_get(nodep));
209 ops->node_put(nodep);
210 }
211 } else {
212 ipc_answer_0(rid, ENOSPC);
213 }
214 goto out;
215 } else if (lflag & L_PARENT) {
216 /* return parent */
217 ipc_answer_5(rid, EOK, fs_handle, dev_handle,
218 ops->index_get(cur), ops->size_get(cur),
219 ops->lnkcnt_get(cur));
220 }
221 ipc_answer_0(rid, ENOENT);
222 goto out;
223 }
224
225 if (par)
226 ops->node_put(par);
227
228 /* descend one level */
229 par = cur;
230 cur = tmp;
231 tmp = NULL;
232 }
233
234 /* handle miss: excessive components */
235 if (!ops->has_children(cur) && next <= last) {
236 if (lflag & (L_CREATE | L_LINK)) {
237 if (!ops->is_directory(cur)) {
238 ipc_answer_0(rid, ENOTDIR);
239 goto out;
240 }
241
242 /* collect next component */
243 len = 0;
244 while (next <= last) {
245 if (ops->plb_get_char(next) == '/') {
246 /* more than one component */
247 ipc_answer_0(rid, ENOENT);
248 goto out;
249 }
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 assert(len);
259 component[len] = '\0';
260
261 void *nodep;
262 if (lflag & L_CREATE)
263 nodep = ops->create(lflag);
264 else
265 nodep = ops->node_get(dev_handle, index);
266 if (nodep) {
267 if (!ops->link(cur, nodep, component)) {
268 if (lflag & L_CREATE)
269 (void)ops->destroy(nodep);
270 ipc_answer_0(rid, ENOSPC);
271 } else {
272 ipc_answer_5(rid, EOK,
273 fs_handle, dev_handle,
274 ops->index_get(nodep),
275 ops->size_get(nodep),
276 ops->lnkcnt_get(nodep));
277 ops->node_put(nodep);
278 }
279 } else {
280 ipc_answer_0(rid, ENOSPC);
281 }
282 goto out;
283 }
284 ipc_answer_0(rid, ENOENT);
285 goto out;
286 }
287
288 /* handle hit */
289 if (lflag & L_PARENT) {
290 ops->node_put(cur);
291 cur = par;
292 par = NULL;
293 if (!cur) {
294 ipc_answer_0(rid, ENOENT);
295 goto out;
296 }
297 }
298 if (lflag & L_UNLINK) {
299 unsigned old_lnkcnt = ops->lnkcnt_get(cur);
300 int res = ops->unlink(par, cur);
301 ipc_answer_5(rid, (ipcarg_t)res, fs_handle, dev_handle,
302 ops->index_get(cur), ops->size_get(cur), old_lnkcnt);
303 goto out;
304 }
305 if (((lflag & (L_CREATE | L_EXCLUSIVE)) == (L_CREATE | L_EXCLUSIVE)) ||
306 (lflag & L_LINK)) {
307 ipc_answer_0(rid, EEXIST);
308 goto out;
309 }
310 if ((lflag & L_FILE) && (ops->is_directory(cur))) {
311 ipc_answer_0(rid, EISDIR);
312 goto out;
313 }
314 if ((lflag & L_DIRECTORY) && (ops->is_file(cur))) {
315 ipc_answer_0(rid, ENOTDIR);
316 goto out;
317 }
318
319 ipc_answer_5(rid, EOK, fs_handle, dev_handle, ops->index_get(cur),
320 ops->size_get(cur), ops->lnkcnt_get(cur));
321
322out:
323 if (par)
324 ops->node_put(par);
325 if (cur)
326 ops->node_put(cur);
327 if (tmp)
328 ops->node_put(tmp);
329}
330
331/** @}
332 */
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