source: mainline/uspace/lib/libfs/libfs.c@ 1e50f81

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 1e50f81 was 1e50f81, checked in by Jakub Jermar <jakub@…>, 18 years ago

Add a comment to libfs_lookup.
  • Property mode set to 100644
File size: 7.5 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 * @param ops libfs operations structure with function pointers to
128 * file system implementation
129 * @param fs_handle File system handle of the file system where to perform
130 * the lookup.
131 * @param rid Request ID of the VFS_LOOKUP request.
132 * @param request VFS_LOOKUP request data itself.
133 */
134void libfs_lookup(libfs_ops_t *ops, int fs_handle, ipc_callid_t rid,
135 ipc_call_t *request)
136{
137 unsigned next = IPC_GET_ARG1(*request);
138 unsigned last = IPC_GET_ARG2(*request);
139 int dev_handle = IPC_GET_ARG3(*request);
140 int lflag = IPC_GET_ARG4(*request);
141
142 if (last < next)
143 last += PLB_SIZE;
144
145 void *cur = ops->root_get();
146 void *tmp = ops->child_get(cur);
147
148 if (ops->plb_get_char(next) == '/')
149 next++; /* eat slash */
150
151 char component[NAME_MAX + 1];
152 int len = 0;
153 while (tmp && next <= last) {
154
155 /* collect the component */
156 if (ops->plb_get_char(next) != '/') {
157 if (len + 1 == NAME_MAX) {
158 /* comopnent length overflow */
159 ipc_answer_0(rid, ENAMETOOLONG);
160 return;
161 }
162 component[len++] = ops->plb_get_char(next);
163 next++; /* process next character */
164 if (next <= last)
165 continue;
166 }
167
168 assert(len);
169 component[len] = '\0';
170 next++; /* eat slash */
171 len = 0;
172
173 /* match the component */
174 while (tmp && !ops->match(tmp, component))
175 tmp = ops->sibling_get(tmp);
176
177 /* handle miss: match amongst siblings */
178 if (!tmp) {
179 if ((next > last) && (lflag & L_CREATE)) {
180 /* no components left and L_CREATE specified */
181 if (!ops->is_directory(cur)) {
182 ipc_answer_0(rid, ENOTDIR);
183 return;
184 }
185 void *nodep = ops->create(lflag);
186 if (nodep) {
187 if (!ops->link(cur, nodep, component)) {
188 ops->destroy(nodep);
189 ipc_answer_0(rid, ENOSPC);
190 } else {
191 ipc_answer_5(rid, EOK,
192 fs_handle, dev_handle,
193 ops->index_get(nodep), 0,
194 ops->lnkcnt_get(nodep));
195 }
196 } else {
197 ipc_answer_0(rid, ENOSPC);
198 }
199 return;
200 }
201 ipc_answer_0(rid, ENOENT);
202 return;
203 }
204
205 /* descend one level */
206 cur = tmp;
207 tmp = ops->child_get(tmp);
208 }
209
210 /* handle miss: excessive components */
211 if (!tmp && next <= last) {
212 if (lflag & L_CREATE) {
213 if (!ops->is_directory(cur)) {
214 ipc_answer_0(rid, ENOTDIR);
215 return;
216 }
217
218 /* collect next component */
219 while (next <= last) {
220 if (ops->plb_get_char(next) == '/') {
221 /* more than one component */
222 ipc_answer_0(rid, ENOENT);
223 return;
224 }
225 if (len + 1 == NAME_MAX) {
226 /* component length overflow */
227 ipc_answer_0(rid, ENAMETOOLONG);
228 return;
229 }
230 component[len++] = ops->plb_get_char(next);
231 next++; /* process next character */
232 }
233 assert(len);
234 component[len] = '\0';
235 len = 0;
236
237 void *nodep = ops->create(lflag);
238 if (nodep) {
239 if (!ops->link(cur, nodep, component)) {
240 ops->destroy(nodep);
241 ipc_answer_0(rid, ENOSPC);
242 } else {
243 ipc_answer_5(rid, EOK,
244 fs_handle, dev_handle,
245 ops->index_get(nodep), 0,
246 ops->lnkcnt_get(nodep));
247 }
248 } else {
249 ipc_answer_0(rid, ENOSPC);
250 }
251 return;
252 }
253 ipc_answer_0(rid, ENOENT);
254 return;
255 }
256
257 /* handle hit */
258 if (lflag & L_DESTROY) {
259 unsigned old_lnkcnt = ops->lnkcnt_get(cur);
260 int res = ops->unlink(cur);
261 ipc_answer_5(rid, (ipcarg_t)res, fs_handle, dev_handle,
262 ops->index_get(cur), ops->size_get(cur), old_lnkcnt);
263 return;
264 }
265 if ((lflag & (L_CREATE | L_EXCLUSIVE)) == (L_CREATE | L_EXCLUSIVE)) {
266 ipc_answer_0(rid, EEXIST);
267 return;
268 }
269 if ((lflag & L_FILE) && (ops->is_directory(cur))) {
270 ipc_answer_0(rid, EISDIR);
271 return;
272 }
273 if ((lflag & L_DIRECTORY) && (ops->is_file(cur))) {
274 ipc_answer_0(rid, ENOTDIR);
275 return;
276 }
277
278 ipc_answer_5(rid, EOK, fs_handle, dev_handle, ops->index_get(cur),
279 ops->size_get(cur), ops->lnkcnt_get(cur));
280}
281
282/** @}
283 */
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