fs/nfs/nfsroot.c

   1 /*
   2  *  $Id: nfsroot.c,v 1.45 1998/03/07 10:44:46 mj Exp $
   3  *
   4  *  Copyright (C) 1995, 1996  Gero Kuhlmann <gero@gkminix.han.de>
   5  *
   6  *  Allow an NFS filesystem to be mounted as root. The way this works is:
   7  *     (1) Use the IP autoconfig mechanism to set local IP addresses and routes.
   8  *     (2) Handle RPC negotiation with the system which replied to RARP or
   9  *         was reported as a boot server by BOOTP or manually.
  10  *     (3) The actual mounting is done later, when init() is running.
  11  *
  12  *
  13  *      Changes:
  14  *
  15  *      Alan Cox        :       Removed get_address name clash with FPU.
  16  *      Alan Cox        :       Reformatted a bit.
  17  *      Gero Kuhlmann   :       Code cleanup
  18  *      Michael Rausch  :       Fixed recognition of an incoming RARP answer.
  19  *      Martin Mares    : (2.0) Auto-configuration via BOOTP supported.
  20  *      Martin Mares    :       Manual selection of interface & BOOTP/RARP.
  21  *      Martin Mares    :       Using network routes instead of host routes,
  22  *                              allowing the default configuration to be used
  23  *                              for normal operation of the host.
  24  *      Martin Mares    :       Randomized timer with exponential backoff
  25  *                              installed to minimize network congestion.
  26  *      Martin Mares    :       Code cleanup.
  27  *      Martin Mares    : (2.1) BOOTP and RARP made configuration options.
  28  *      Martin Mares    :       Server hostname generation fixed.
  29  *      Gerd Knorr      :       Fixed wired inode handling
  30  *      Martin Mares    : (2.2) "0.0.0.0" addresses from command line ignored.
  31  *      Martin Mares    :       RARP replies not tested for server address.
  32  *      Gero Kuhlmann   : (2.3) Some bug fixes and code cleanup again (please
  33  *                              send me your new patches _before_ bothering
  34  *                              Linus so that I don' always have to cleanup
  35  *                              _afterwards_ - thanks)
  36  *      Gero Kuhlmann   :       Last changes of Martin Mares undone.
  37  *      Gero Kuhlmann   :       RARP replies are tested for specified server
  38  *                              again. However, it's now possible to have
  39  *                              different RARP and NFS servers.
  40  *      Gero Kuhlmann   :       "0.0.0.0" addresses from command line are
  41  *                              now mapped to INADDR_NONE.
  42  *      Gero Kuhlmann   :       Fixed a bug which prevented BOOTP path name
  43  *                              from being used (thanks to Leo Spiekman)
  44  *      Andy Walker     :       Allow to specify the NFS server in nfs_root
  45  *                              without giving a path name
  46  *      Swen Thümmler   :       Allow to specify the NFS options in nfs_root
  47  *                              without giving a path name. Fix BOOTP request
  48  *                              for domainname (domainname is NIS domain, not
  49  *                              DNS domain!). Skip dummy devices for BOOTP.
  50  *      Jacek Zapala    :       Fixed a bug which prevented server-ip address
  51  *                              from nfsroot parameter from being used.
  52  *      Olaf Kirch      :       Adapted to new NFS code.
  53  *      Jakub Jelinek   :       Free used code segment.
  54  *      Marko Kohtala   :       Fixed some bugs.
  55  *      Martin Mares    :       Debug message cleanup
  56  *      Martin Mares    :       Changed to use the new generic IP layer autoconfig
  57  *                              code. BOOTP and RARP moved there.
  58  *      Martin Mares    :       Default path now contains host name instead of
  59  *                              host IP address (but host name defaults to IP
  60  *                              address anyway).
  61  *      Martin Mares    :       Use root_server_addr appropriately during setup.
  62  *      Martin Mares    :       Rewrote parameter parsing, now hopefully giving
  63  *                              correct overriding.
  64  *      Trond Myklebust :       Add in preliminary support for NFSv3 and TCP.
  65  *                              Fix bug in root_nfs_addr(). nfs_data.namlen
  66  *                              is NOT for the length of the hostname.
  67  *      Hua Qin         :       Support for mounting root file system via
  68  *                              NFS over TCP.
  69  *      Fabian Frederick:       Option parser rebuilt (using parser lib)
  70 */
  71
  72 #include <linux/types.h>
  73 #include <linux/string.h>
  74 #include <linux/kernel.h>
  75 #include <linux/time.h>
  76 #include <linux/fs.h>
  77 #include <linux/init.h>
  78 #include <linux/sunrpc/clnt.h>
  79 #include <linux/nfs.h>
  80 #include <linux/nfs_fs.h>
  81 #include <linux/nfs_mount.h>
  82 #include <linux/in.h>
  83 #include <linux/major.h>
  84 #include <linux/utsname.h>
  85 #include <linux/inet.h>
  86 #include <linux/root_dev.h>
  87 #include <net/ipconfig.h>
  88 #include <linux/parser.h>
  89
  90 /* Define this to allow debugging output */
  91 #undef NFSROOT_DEBUG
  92 #define NFSDBG_FACILITY NFSDBG_ROOT
  93
  94 /* Default path we try to mount. "%s" gets replaced by our IP address */
  95 #define NFS_ROOT                "/tftpboot/%s"
  96
  97 /* Parameters passed from the kernel command line */
  98 static char nfs_root_name[256] __initdata = "";
  99
 100 /* Address of NFS server */
 101 static __be32 servaddr __initdata = 0;
 102
 103 /* Name of directory to mount */
 104 static char nfs_path[NFS_MAXPATHLEN] __initdata = { 0, };
 105
 106 /* NFS-related data */
 107 static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
 108 static int nfs_port __initdata = 0;             /* Port to connect to for NFS */
 109 static int mount_port __initdata = 0;           /* Mount daemon port number */
 110
 111
 112 /***************************************************************************
 113
 114                              Parsing of options
 115
 116  ***************************************************************************/
 117
 118 enum {
 119         /* Options that take integer arguments */
 120         Opt_port, Opt_rsize, Opt_wsize, Opt_timeo, Opt_retrans, Opt_acregmin,
 121         Opt_acregmax, Opt_acdirmin, Opt_acdirmax,
 122         /* Options that take no arguments */
 123         Opt_soft, Opt_hard, Opt_intr,
 124         Opt_nointr, Opt_posix, Opt_noposix, Opt_cto, Opt_nocto, Opt_ac,
 125         Opt_noac, Opt_lock, Opt_nolock, Opt_v2, Opt_v3, Opt_udp, Opt_tcp,
 126         Opt_acl, Opt_noacl,
 127         /* Error token */
 128         Opt_err
 129 };
 130
 131 static match_table_t __initdata tokens = {
 132         {Opt_port, "port=%u"},
 133         {Opt_rsize, "rsize=%u"},
 134         {Opt_wsize, "wsize=%u"},
 135         {Opt_timeo, "timeo=%u"},
 136         {Opt_retrans, "retrans=%u"},
 137         {Opt_acregmin, "acregmin=%u"},
 138         {Opt_acregmax, "acregmax=%u"},
 139         {Opt_acdirmin, "acdirmin=%u"},
 140         {Opt_acdirmax, "acdirmax=%u"},
 141         {Opt_soft, "soft"},
 142         {Opt_hard, "hard"},
 143         {Opt_intr, "intr"},
 144         {Opt_nointr, "nointr"},
 145         {Opt_posix, "posix"},
 146         {Opt_noposix, "noposix"},
 147         {Opt_cto, "cto"},
 148         {Opt_nocto, "nocto"},
 149         {Opt_ac, "ac"},
 150         {Opt_noac, "noac"},
 151         {Opt_lock, "lock"},
 152         {Opt_nolock, "nolock"},
 153         {Opt_v2, "nfsvers=2"},
 154         {Opt_v2, "v2"},
 155         {Opt_v3, "nfsvers=3"},
 156         {Opt_v3, "v3"},
 157         {Opt_udp, "proto=udp"},
 158         {Opt_udp, "udp"},
 159         {Opt_tcp, "proto=tcp"},
 160         {Opt_tcp, "tcp"},
 161         {Opt_acl, "acl"},
 162         {Opt_noacl, "noacl"},
 163         {Opt_err, NULL}
 164
 165 };
 166
 167 /*
 168  *  Parse option string.
 169  */
 170
 171 static int __init root_nfs_parse(char *name, char *buf)
 172 {
 173
 174         char *p;
 175         substring_t args[MAX_OPT_ARGS];
 176         int option;
 177
 178         if (!name)
 179                 return 1;
 180
 181         /* Set the NFS remote path */
 182         p = strsep(&name, ",");
 183         if (p[0] != '\0' && strcmp(p, "default") != 0)
 184                 strlcpy(buf, p, NFS_MAXPATHLEN);
 185
 186         while ((p = strsep (&name, ",")) != NULL) {
 187                 int token;
 188                 if (!*p)
 189                         continue;
 190                 token = match_token(p, tokens, args);
 191
 192                 /* %u tokens only. Beware if you add new tokens! */
 193                 if (token < Opt_soft && match_int(&args[0], &option))
 194                         return 0;
 195                 switch (token) {
 196                         case Opt_port:
 197                                 nfs_port = option;
 198                                 break;
 199                         case Opt_rsize:
 200                                 nfs_data.rsize = option;
 201                                 break;
 202                         case Opt_wsize:
 203                                 nfs_data.wsize = option;
 204                                 break;
 205                         case Opt_timeo:
 206                                 nfs_data.timeo = option;
 207                                 break;
 208                         case Opt_retrans:
 209                                 nfs_data.retrans = option;
 210                                 break;
 211                         case Opt_acregmin:
 212                                 nfs_data.acregmin = option;
 213                                 break;
 214                         case Opt_acregmax:
 215                                 nfs_data.acregmax = option;
 216                                 break;
 217                         case Opt_acdirmin:
 218                                 nfs_data.acdirmin = option;
 219                                 break;
 220                         case Opt_acdirmax:
 221                                 nfs_data.acdirmax = option;
 222                                 break;
 223                         case Opt_soft:
 224                                 nfs_data.flags |= NFS_MOUNT_SOFT;
 225                                 break;
 226                         case Opt_hard:
 227                                 nfs_data.flags &= ~NFS_MOUNT_SOFT;
 228                                 break;
 229                         case Opt_intr:
 230                                 nfs_data.flags |= NFS_MOUNT_INTR;
 231                                 break;
 232                         case Opt_nointr:
 233                                 nfs_data.flags &= ~NFS_MOUNT_INTR;
 234                                 break;
 235                         case Opt_posix:
 236                                 nfs_data.flags |= NFS_MOUNT_POSIX;
 237                                 break;
 238                         case Opt_noposix:
 239                                 nfs_data.flags &= ~NFS_MOUNT_POSIX;
 240                                 break;
 241                         case Opt_cto:
 242                                 nfs_data.flags &= ~NFS_MOUNT_NOCTO;
 243                                 break;
 244                         case Opt_nocto:
 245                                 nfs_data.flags |= NFS_MOUNT_NOCTO;
 246                                 break;
 247                         case Opt_ac:
 248                                 nfs_data.flags &= ~NFS_MOUNT_NOAC;
 249                                 break;
 250                         case Opt_noac:
 251                                 nfs_data.flags |= NFS_MOUNT_NOAC;
 252                                 break;
 253                         case Opt_lock:
 254                                 nfs_data.flags &= ~NFS_MOUNT_NONLM;
 255                                 break;
 256                         case Opt_nolock:
 257                                 nfs_data.flags |= NFS_MOUNT_NONLM;
 258                                 break;
 259                         case Opt_v2:
 260                                 nfs_data.flags &= ~NFS_MOUNT_VER3;
 261                                 break;
 262                         case Opt_v3:
 263                                 nfs_data.flags |= NFS_MOUNT_VER3;
 264                                 break;
 265                         case Opt_udp:
 266                                 nfs_data.flags &= ~NFS_MOUNT_TCP;
 267                                 break;
 268                         case Opt_tcp:
 269                                 nfs_data.flags |= NFS_MOUNT_TCP;
 270                                 break;
 271                         case Opt_acl:
 272                                 nfs_data.flags &= ~NFS_MOUNT_NOACL;
 273                                 break;
 274                         case Opt_noacl:
 275                                 nfs_data.flags |= NFS_MOUNT_NOACL;
 276                                 break;
 277                         default:
 278                                 printk(KERN_WARNING "Root-NFS: unknown "
 279                                         "option: %s\n", p);
 280                                 return 0;
 281                 }
 282         }
 283
 284         return 1;
 285 }
 286
 287 /*
 288  *  Prepare the NFS data structure and parse all options.
 289  */
 290 static int __init root_nfs_name(char *name)
 291 {
 292         static char buf[NFS_MAXPATHLEN] __initdata;
 293         char *cp;
 294
 295         /* Set some default values */
 296         memset(&nfs_data, 0, sizeof(nfs_data));
 297         nfs_port          = -1;
 298         nfs_data.version  = NFS_MOUNT_VERSION;
 299         nfs_data.flags    = NFS_MOUNT_NONLM;    /* No lockd in nfs root yet */
 300         nfs_data.rsize    = NFS_DEF_FILE_IO_SIZE;
 301         nfs_data.wsize    = NFS_DEF_FILE_IO_SIZE;
 302         nfs_data.acregmin = 3;
 303         nfs_data.acregmax = 60;
 304         nfs_data.acdirmin = 30;
 305         nfs_data.acdirmax = 60;
 306         strcpy(buf, NFS_ROOT);
 307
 308         /* Process options received from the remote server */
 309         root_nfs_parse(root_server_path, buf);
 310
 311         /* Override them by options set on kernel command-line */
 312         root_nfs_parse(name, buf);
 313
 314         cp = utsname()->nodename;
 315         if (strlen(buf) + strlen(cp) > NFS_MAXPATHLEN) {
 316                 printk(KERN_ERR "Root-NFS: Pathname for remote directory too long.\n");
 317                 return -1;
 318         }
 319         sprintf(nfs_path, buf, cp);
 320
 321         return 1;
 322 }
 323
 324
 325 /*
 326  *  Get NFS server address.
 327  */
 328 static int __init root_nfs_addr(void)
 329 {
 330         if ((servaddr = root_server_addr) == htonl(INADDR_NONE)) {
 331                 printk(KERN_ERR "Root-NFS: No NFS server available, giving up.\n");
 332                 return -1;
 333         }
 334
 335         snprintf(nfs_data.hostname, sizeof(nfs_data.hostname),
 336                  "%u.%u.%u.%u", NIPQUAD(servaddr));
 337         return 0;
 338 }
 339
 340 /*
 341  *  Tell the user what's going on.
 342  */
 343 #ifdef NFSROOT_DEBUG
 344 static void __init root_nfs_print(void)
 345 {
 346         printk(KERN_NOTICE "Root-NFS: Mounting %s on server %s as root\n",
 347                 nfs_path, nfs_data.hostname);
 348         printk(KERN_NOTICE "Root-NFS:     rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
 349                 nfs_data.rsize, nfs_data.wsize, nfs_data.timeo, nfs_data.retrans);
 350         printk(KERN_NOTICE "Root-NFS:     acreg (min,max) = (%d,%d), acdir (min,max) = (%d,%d)\n",
 351                 nfs_data.acregmin, nfs_data.acregmax,
 352                 nfs_data.acdirmin, nfs_data.acdirmax);
 353         printk(KERN_NOTICE "Root-NFS:     nfsd port = %d, mountd port = %d, flags = %08x\n",
 354                 nfs_port, mount_port, nfs_data.flags);
 355 }
 356 #endif
 357
 358
 359 static int __init root_nfs_init(void)
 360 {
 361 #ifdef NFSROOT_DEBUG
 362         nfs_debug |= NFSDBG_ROOT;
 363 #endif
 364
 365         /*
 366          * Decode the root directory path name and NFS options from
 367          * the kernel command line. This has to go here in order to
 368          * be able to use the client IP address for the remote root
 369          * directory (necessary for pure RARP booting).
 370          */
 371         if (root_nfs_name(nfs_root_name) < 0 ||
 372             root_nfs_addr() < 0)
 373                 return -1;
 374
 375 #ifdef NFSROOT_DEBUG
 376         root_nfs_print();
 377 #endif
 378
 379         return 0;
 380 }
 381
 382
 383 /*
 384  *  Parse NFS server and directory information passed on the kernel
 385  *  command line.
 386  */
 387 static int __init nfs_root_setup(char *line)
 388 {
 389         ROOT_DEV = Root_NFS;
 390         if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
 391                 strlcpy(nfs_root_name, line, sizeof(nfs_root_name));
 392         } else {
 393                 int n = strlen(line) + sizeof(NFS_ROOT) - 1;
 394                 if (n >= sizeof(nfs_root_name))
 395                         line[sizeof(nfs_root_name) - sizeof(NFS_ROOT) - 2] = '\0';
 396                 sprintf(nfs_root_name, NFS_ROOT, line);
 397         }
 398         root_server_addr = root_nfs_parse_addr(nfs_root_name);
 399         return 1;
 400 }
 401
 402 __setup("nfsroot=", nfs_root_setup);
 403
 404 /***************************************************************************
 405
 406                Routines to actually mount the root directory
 407
 408  ***************************************************************************/
 409
 410 /*
 411  *  Construct sockaddr_in from address and port number.
 412  */
 413 static inline void
 414 set_sockaddr(struct sockaddr_in *sin, __be32 addr, __be16 port)
 415 {
 416         sin->sin_family = AF_INET;
 417         sin->sin_addr.s_addr = addr;
 418         sin->sin_port = port;
 419 }
 420
 421 /*
 422  *  Query server portmapper for the port of a daemon program.
 423  */
 424 static int __init root_nfs_getport(int program, int version, int proto)
 425 {
 426         struct sockaddr_in sin;
 427
 428         printk(KERN_NOTICE "Looking up port of RPC %d/%d on %u.%u.%u.%u\n",
 429                 program, version, NIPQUAD(servaddr));
 430         set_sockaddr(&sin, servaddr, 0);
 431         return rpcb_getport_sync(&sin, program, version, proto);
 432 }
 433
 434
 435 /*
 436  *  Use portmapper to find mountd and nfsd port numbers if not overriden
 437  *  by the user. Use defaults if portmapper is not available.
 438  *  XXX: Is there any nfs server with no portmapper?
 439  */
 440 static int __init root_nfs_ports(void)
 441 {
 442         int port;
 443         int nfsd_ver, mountd_ver;
 444         int nfsd_port, mountd_port;
 445         int proto;
 446
 447         if (nfs_data.flags & NFS_MOUNT_VER3) {
 448                 nfsd_ver = NFS3_VERSION;
 449                 mountd_ver = NFS_MNT3_VERSION;
 450                 nfsd_port = NFS_PORT;
 451                 mountd_port = NFS_MNT_PORT;
 452         } else {
 453                 nfsd_ver = NFS2_VERSION;
 454                 mountd_ver = NFS_MNT_VERSION;
 455                 nfsd_port = NFS_PORT;
 456                 mountd_port = NFS_MNT_PORT;
 457         }
 458
 459         proto = (nfs_data.flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;
 460
 461         if (nfs_port < 0) {
 462                 if ((port = root_nfs_getport(NFS_PROGRAM, nfsd_ver, proto)) < 0) {
 463                         printk(KERN_ERR "Root-NFS: Unable to get nfsd port "
 464                                         "number from server, using default\n");
 465                         port = nfsd_port;
 466                 }
 467                 nfs_port = port;
 468                 dprintk("Root-NFS: Portmapper on server returned %d "
 469                         "as nfsd port\n", port);
 470         }
 471
 472         if ((port = root_nfs_getport(NFS_MNT_PROGRAM, mountd_ver, proto)) < 0) {
 473                 printk(KERN_ERR "Root-NFS: Unable to get mountd port "
 474                                 "number from server, using default\n");
 475                 port = mountd_port;
 476         }
 477         mount_port = port;
 478         dprintk("Root-NFS: mountd port is %d\n", port);
 479
 480         return 0;
 481 }
 482
 483
 484 /*
 485  *  Get a file handle from the server for the directory which is to be
 486  *  mounted.
 487  */
 488 static int __init root_nfs_get_handle(void)
 489 {
 490         struct nfs_fh fh;
 491         struct sockaddr_in sin;
 492         int status;
 493         int protocol = (nfs_data.flags & NFS_MOUNT_TCP) ?
 494                                         IPPROTO_TCP : IPPROTO_UDP;
 495         int version = (nfs_data.flags & NFS_MOUNT_VER3) ?
 496                                         NFS_MNT3_VERSION : NFS_MNT_VERSION;
 497
 498         set_sockaddr(&sin, servaddr, htons(mount_port));
 499         status = nfs_mount((struct sockaddr *) &sin, sizeof(sin), NULL,
 500                            nfs_path, version, protocol, &fh);
 501         if (status < 0)
 502                 printk(KERN_ERR "Root-NFS: Server returned error %d "
 503                                 "while mounting %s\n", status, nfs_path);
 504         else {
 505                 nfs_data.root.size = fh.size;
 506                 memcpy(nfs_data.root.data, fh.data, fh.size);
 507         }
 508
 509         return status;
 510 }
 511
 512 /*
 513  *  Get the NFS port numbers and file handle, and return the prepared 'data'
 514  *  argument for mount() if everything went OK. Return NULL otherwise.
 515  */
 516 void * __init nfs_root_data(void)
 517 {
 518         if (root_nfs_init() < 0
 519          || root_nfs_ports() < 0
 520          || root_nfs_get_handle() < 0)
 521                 return NULL;
 522         set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, htons(nfs_port));
 523         return (void*)&nfs_data;
 524 }