fs/nfs/nfsroot.c

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