xref: /openbmc/linux/fs/9p/v9fs.c (revision 22246614)
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/transport.h>
34 #include <net/9p/client.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 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  * @options: options string passed from mount
75  * @v9ses: existing v9fs session information
76  *
77  */
78 
79 static void 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;
87 
88 	/* setup defaults */
89 	v9ses->afid = ~0;
90 	v9ses->debug = 0;
91 	v9ses->cache = 0;
92 
93 	if (!v9ses->options)
94 		return;
95 
96 	options = kstrdup(v9ses->options, GFP_KERNEL);
97 	while ((p = strsep(&options, ",")) != NULL) {
98 		int token;
99 		if (!*p)
100 			continue;
101 		token = match_token(p, tokens, args);
102 		if (token < Opt_uname) {
103 			ret = match_int(&args[0], &option);
104 			if (ret < 0) {
105 				P9_DPRINTK(P9_DEBUG_ERROR,
106 					"integer field, but no integer?\n");
107 				continue;
108 			}
109 		}
110 		switch (token) {
111 		case Opt_debug:
112 			v9ses->debug = option;
113 #ifdef CONFIG_NET_9P_DEBUG
114 			p9_debug_level = option;
115 #endif
116 			break;
117 
118 		case Opt_dfltuid:
119 			v9ses->dfltuid = option;
120 			break;
121 		case Opt_dfltgid:
122 			v9ses->dfltgid = option;
123 			break;
124 		case Opt_afid:
125 			v9ses->afid = option;
126 			break;
127 		case Opt_uname:
128 			match_strcpy(v9ses->uname, &args[0]);
129 			break;
130 		case Opt_remotename:
131 			match_strcpy(v9ses->aname, &args[0]);
132 			break;
133 		case Opt_nodevmap:
134 			v9ses->nodev = 1;
135 			break;
136 		case Opt_cache_loose:
137 			v9ses->cache = CACHE_LOOSE;
138 			break;
139 
140 		case Opt_access:
141 			s = match_strdup(&args[0]);
142 			v9ses->flags &= ~V9FS_ACCESS_MASK;
143 			if (strcmp(s, "user") == 0)
144 				v9ses->flags |= V9FS_ACCESS_USER;
145 			else if (strcmp(s, "any") == 0)
146 				v9ses->flags |= V9FS_ACCESS_ANY;
147 			else {
148 				v9ses->flags |= V9FS_ACCESS_SINGLE;
149 				v9ses->uid = simple_strtol(s, &e, 10);
150 				if (*e != '\0')
151 					v9ses->uid = ~0;
152 			}
153 			kfree(s);
154 			break;
155 
156 		default:
157 			continue;
158 		}
159 	}
160 	kfree(options);
161 }
162 
163 /**
164  * v9fs_session_init - initialize session
165  * @v9ses: session information structure
166  * @dev_name: device being mounted
167  * @data: options
168  *
169  */
170 
171 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
172 		  const char *dev_name, char *data)
173 {
174 	int retval = -EINVAL;
175 	struct p9_fid *fid;
176 
177 	v9ses->uname = __getname();
178 	if (!v9ses->uname)
179 		return ERR_PTR(-ENOMEM);
180 
181 	v9ses->aname = __getname();
182 	if (!v9ses->aname) {
183 		__putname(v9ses->uname);
184 		return ERR_PTR(-ENOMEM);
185 	}
186 
187 	v9ses->flags = V9FS_EXTENDED | V9FS_ACCESS_USER;
188 	strcpy(v9ses->uname, V9FS_DEFUSER);
189 	strcpy(v9ses->aname, V9FS_DEFANAME);
190 	v9ses->uid = ~0;
191 	v9ses->dfltuid = V9FS_DEFUID;
192 	v9ses->dfltgid = V9FS_DEFGID;
193 	v9ses->options = kstrdup(data, GFP_KERNEL);
194 	v9fs_parse_options(v9ses);
195 
196 	v9ses->clnt = p9_client_create(dev_name, v9ses->options);
197 
198 	if (IS_ERR(v9ses->clnt)) {
199 		retval = PTR_ERR(v9ses->clnt);
200 		v9ses->clnt = NULL;
201 		P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
202 		goto error;
203 	}
204 
205 	if (!v9ses->clnt->dotu)
206 		v9ses->flags &= ~V9FS_EXTENDED;
207 
208 	v9ses->maxdata = v9ses->clnt->msize;
209 
210 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
211 	if (!v9fs_extended(v9ses) &&
212 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
213 
214 		v9ses->flags &= ~V9FS_ACCESS_MASK;
215 		v9ses->flags |= V9FS_ACCESS_ANY;
216 		v9ses->uid = ~0;
217 	}
218 
219 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
220 							v9ses->aname);
221 	if (IS_ERR(fid)) {
222 		retval = PTR_ERR(fid);
223 		fid = NULL;
224 		P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
225 		goto error;
226 	}
227 
228 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
229 		fid->uid = v9ses->uid;
230 	else
231 		fid->uid = ~0;
232 
233 	return fid;
234 
235 error:
236 	v9fs_session_close(v9ses);
237 	return ERR_PTR(retval);
238 }
239 
240 /**
241  * v9fs_session_close - shutdown a session
242  * @v9ses: session information structure
243  *
244  */
245 
246 void v9fs_session_close(struct v9fs_session_info *v9ses)
247 {
248 	if (v9ses->clnt) {
249 		p9_client_destroy(v9ses->clnt);
250 		v9ses->clnt = NULL;
251 	}
252 
253 	__putname(v9ses->uname);
254 	__putname(v9ses->aname);
255 	kfree(v9ses->options);
256 }
257 
258 /**
259  * v9fs_session_cancel - mark transport as disconnected
260  * 	and cancel all pending requests.
261  */
262 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
263 	P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
264 	p9_client_disconnect(v9ses->clnt);
265 }
266 
267 extern int v9fs_error_init(void);
268 
269 /**
270  * v9fs_init - Initialize module
271  *
272  */
273 
274 static int __init init_v9fs(void)
275 {
276 	printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
277 	/* TODO: Setup list of registered trasnport modules */
278 	return register_filesystem(&v9fs_fs_type);
279 }
280 
281 /**
282  * v9fs_init - shutdown module
283  *
284  */
285 
286 static void __exit exit_v9fs(void)
287 {
288 	unregister_filesystem(&v9fs_fs_type);
289 }
290 
291 module_init(init_v9fs)
292 module_exit(exit_v9fs)
293 
294 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
295 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
296 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
297 MODULE_LICENSE("GPL");
298