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");