9p: move readn meta-function from client to fs layer
[linux-2.6.git] / fs / 9p / v9fs.c
1 /*
2  *  linux/fs/9p/v9fs.c
3  *
4  *  This file contains functions assisting in mapping VFS to 9P2000
5  *
6  *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
7  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License version 2
11  *  as published by the Free Software Foundation.
12  *
13  *  This program is distributed in the hope that it will be useful,
14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *  GNU General Public License for more details.
17  *
18  *  You should have received a copy of the GNU General Public License
19  *  along with this program; if not, write to:
20  *  Free Software Foundation
21  *  51 Franklin Street, Fifth Floor
22  *  Boston, MA  02111-1301  USA
23  *
24  */
25
26 #include <linux/module.h>
27 #include <linux/errno.h>
28 #include <linux/fs.h>
29 #include <linux/sched.h>
30 #include <linux/parser.h>
31 #include <linux/idr.h>
32 #include <net/9p/9p.h>
33 #include <net/9p/client.h>
34 #include <net/9p/transport.h>
35 #include "v9fs.h"
36 #include "v9fs_vfs.h"
37
38 /*
39   * Option Parsing (code inspired by NFS code)
40   *  NOTE: each transport will parse its own options
41   */
42
43 enum {
44         /* Options that take integer arguments */
45         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
46         /* String options */
47         Opt_uname, Opt_remotename, Opt_trans,
48         /* Options that take no arguments */
49         Opt_nodevmap,
50         /* Cache options */
51         Opt_cache_loose,
52         /* Access options */
53         Opt_access,
54         /* Error token */
55         Opt_err
56 };
57
58 static const match_table_t tokens = {
59         {Opt_debug, "debug=%x"},
60         {Opt_dfltuid, "dfltuid=%u"},
61         {Opt_dfltgid, "dfltgid=%u"},
62         {Opt_afid, "afid=%u"},
63         {Opt_uname, "uname=%s"},
64         {Opt_remotename, "aname=%s"},
65         {Opt_nodevmap, "nodevmap"},
66         {Opt_cache_loose, "cache=loose"},
67         {Opt_cache_loose, "loose"},
68         {Opt_access, "access=%s"},
69         {Opt_err, NULL}
70 };
71
72 /**
73  * v9fs_parse_options - parse mount options into session structure
74  * @v9ses: existing v9fs session information
75  *
76  * Return 0 upon success, -ERRNO upon failure.
77  */
78
79 static int v9fs_parse_options(struct v9fs_session_info *v9ses)
80 {
81         char *options;
82         substring_t args[MAX_OPT_ARGS];
83         char *p;
84         int option = 0;
85         char *s, *e;
86         int ret = 0;
87
88         /* setup defaults */
89         v9ses->afid = ~0;
90         v9ses->debug = 0;
91         v9ses->cache = 0;
92
93         if (!v9ses->options)
94                 return 0;
95
96         options = kstrdup(v9ses->options, GFP_KERNEL);
97         if (!options) {
98                 P9_DPRINTK(P9_DEBUG_ERROR,
99                            "failed to allocate copy of option string\n");
100                 return -ENOMEM;
101         }
102
103         while ((p = strsep(&options, ",")) != NULL) {
104                 int token;
105                 if (!*p)
106                         continue;
107                 token = match_token(p, tokens, args);
108                 if (token < Opt_uname) {
109                         int r = match_int(&args[0], &option);
110                         if (r < 0) {
111                                 P9_DPRINTK(P9_DEBUG_ERROR,
112                                         "integer field, but no integer?\n");
113                                 ret = r;
114                                 continue;
115                         }
116                 }
117                 switch (token) {
118                 case Opt_debug:
119                         v9ses->debug = option;
120 #ifdef CONFIG_NET_9P_DEBUG
121                         p9_debug_level = option;
122 #endif
123                         break;
124
125                 case Opt_dfltuid:
126                         v9ses->dfltuid = option;
127                         break;
128                 case Opt_dfltgid:
129                         v9ses->dfltgid = option;
130                         break;
131                 case Opt_afid:
132                         v9ses->afid = option;
133                         break;
134                 case Opt_uname:
135                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
136                         break;
137                 case Opt_remotename:
138                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
139                         break;
140                 case Opt_nodevmap:
141                         v9ses->nodev = 1;
142                         break;
143                 case Opt_cache_loose:
144                         v9ses->cache = CACHE_LOOSE;
145                         break;
146
147                 case Opt_access:
148                         s = match_strdup(&args[0]);
149                         if (!s) {
150                                 P9_DPRINTK(P9_DEBUG_ERROR,
151                                            "failed to allocate copy"
152                                            " of option argument\n");
153                                 ret = -ENOMEM;
154                                 break;
155                         }
156                         v9ses->flags &= ~V9FS_ACCESS_MASK;
157                         if (strcmp(s, "user") == 0)
158                                 v9ses->flags |= V9FS_ACCESS_USER;
159                         else if (strcmp(s, "any") == 0)
160                                 v9ses->flags |= V9FS_ACCESS_ANY;
161                         else {
162                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
163                                 v9ses->uid = simple_strtol(s, &e, 10);
164                                 if (*e != '\0')
165                                         v9ses->uid = ~0;
166                         }
167                         kfree(s);
168                         break;
169
170                 default:
171                         continue;
172                 }
173         }
174         kfree(options);
175         return ret;
176 }
177
178 /**
179  * v9fs_session_init - initialize session
180  * @v9ses: session information structure
181  * @dev_name: device being mounted
182  * @data: options
183  *
184  */
185
186 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
187                   const char *dev_name, char *data)
188 {
189         int retval = -EINVAL;
190         struct p9_fid *fid;
191         int rc;
192
193         v9ses->uname = __getname();
194         if (!v9ses->uname)
195                 return ERR_PTR(-ENOMEM);
196
197         v9ses->aname = __getname();
198         if (!v9ses->aname) {
199                 __putname(v9ses->uname);
200                 return ERR_PTR(-ENOMEM);
201         }
202
203         v9ses->flags = V9FS_EXTENDED | V9FS_ACCESS_USER;
204         strcpy(v9ses->uname, V9FS_DEFUSER);
205         strcpy(v9ses->aname, V9FS_DEFANAME);
206         v9ses->uid = ~0;
207         v9ses->dfltuid = V9FS_DEFUID;
208         v9ses->dfltgid = V9FS_DEFGID;
209         if (data) {
210                 v9ses->options = kstrdup(data, GFP_KERNEL);
211                 if (!v9ses->options) {
212                         P9_DPRINTK(P9_DEBUG_ERROR,
213                            "failed to allocate copy of option string\n");
214                         retval = -ENOMEM;
215                         goto error;
216                 }
217         }
218
219         rc = v9fs_parse_options(v9ses);
220         if (rc < 0) {
221                 retval = rc;
222                 goto error;
223         }
224
225         v9ses->clnt = p9_client_create(dev_name, v9ses->options);
226
227         if (IS_ERR(v9ses->clnt)) {
228                 retval = PTR_ERR(v9ses->clnt);
229                 v9ses->clnt = NULL;
230                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
231                 goto error;
232         }
233
234         if (!v9ses->clnt->dotu)
235                 v9ses->flags &= ~V9FS_EXTENDED;
236
237         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
238
239         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
240         if (!v9fs_extended(v9ses) &&
241                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
242
243                 v9ses->flags &= ~V9FS_ACCESS_MASK;
244                 v9ses->flags |= V9FS_ACCESS_ANY;
245                 v9ses->uid = ~0;
246         }
247
248         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
249                                                         v9ses->aname);
250         if (IS_ERR(fid)) {
251                 retval = PTR_ERR(fid);
252                 fid = NULL;
253                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
254                 goto error;
255         }
256
257         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
258                 fid->uid = v9ses->uid;
259         else
260                 fid->uid = ~0;
261
262         return fid;
263
264 error:
265         return ERR_PTR(retval);
266 }
267
268 /**
269  * v9fs_session_close - shutdown a session
270  * @v9ses: session information structure
271  *
272  */
273
274 void v9fs_session_close(struct v9fs_session_info *v9ses)
275 {
276         if (v9ses->clnt) {
277                 p9_client_destroy(v9ses->clnt);
278                 v9ses->clnt = NULL;
279         }
280
281         __putname(v9ses->uname);
282         __putname(v9ses->aname);
283         kfree(v9ses->options);
284 }
285
286 /**
287  * v9fs_session_cancel - terminate a session
288  * @v9ses: session to terminate
289  *
290  * mark transport as disconnected and cancel all pending requests.
291  */
292
293 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
294         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
295         p9_client_disconnect(v9ses->clnt);
296 }
297
298 extern int v9fs_error_init(void);
299
300 /**
301  * v9fs_init - Initialize module
302  *
303  */
304
305 static int __init init_v9fs(void)
306 {
307         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
308         /* TODO: Setup list of registered trasnport modules */
309         return register_filesystem(&v9fs_fs_type);
310 }
311
312 /**
313  * v9fs_init - shutdown module
314  *
315  */
316
317 static void __exit exit_v9fs(void)
318 {
319         unregister_filesystem(&v9fs_fs_type);
320 }
321
322 module_init(init_v9fs)
323 module_exit(exit_v9fs)
324
325 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
326 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
327 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
328 MODULE_LICENSE("GPL");