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 #include "internal.h"
  90
  91 /* Define this to allow debugging output */
  92 #undef NFSROOT_DEBUG
  93 #define NFSDBG_FACILITY NFSDBG_ROOT
  94
  95 /* Default port to use if server is not running a portmapper */
  96 #define NFS_MNT_PORT    627
  97
  98 /* Default path we try to mount. "%s" gets replaced by our IP address */
  99 #define NFS_ROOT                "/tftpboot/%s"
 100
 101 /* Parameters passed from the kernel command line */
 102 static char nfs_root_name[256] __initdata = "";
 103
 104 /* Address of NFS server */
 105 static __be32 servaddr __initdata = 0;
 106
 107 /* Name of directory to mount */
 108 static char nfs_export_path[NFS_MAXPATHLEN] __initdata = { 0, };
 109
 110 /* NFS-related data */
 111 static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
 112 static int nfs_port __initdata = 0;             /* Port to connect to for NFS */
 113 static int mount_port __initdata = 0;           /* Mount daemon port number */
 114
 115
 116 /***************************************************************************
 117
 118                              Parsing of options
 119
 120  ***************************************************************************/
 121
 122 enum {
 123         /* Options that take integer arguments */
 124         Opt_port, Opt_rsize, Opt_wsize, Opt_timeo, Opt_retrans, Opt_acregmin,
 125         Opt_acregmax, Opt_acdirmin, Opt_acdirmax,
 126         /* Options that take no arguments */
 127         Opt_soft, Opt_hard, Opt_intr,
 128         Opt_nointr, Opt_posix, Opt_noposix, Opt_cto, Opt_nocto, Opt_ac,
 129         Opt_noac, Opt_lock, Opt_nolock, Opt_v2, Opt_v3, Opt_udp, Opt_tcp,
 130         Opt_acl, Opt_noacl,
 131         /* Error token */
 132         Opt_err
 133 };
 134
 135 static const match_table_t tokens __initconst = {
 136         {Opt_port, "port=%u"},
 137         {Opt_rsize, "rsize=%u"},
 138         {Opt_wsize, "wsize=%u"},
 139         {Opt_timeo, "timeo=%u"},
 140         {Opt_retrans, "retrans=%u"},
 141         {Opt_acregmin, "acregmin=%u"},
 142         {Opt_acregmax, "acregmax=%u"},
 143         {Opt_acdirmin, "acdirmin=%u"},
 144         {Opt_acdirmax, "acdirmax=%u"},
 145         {Opt_soft, "soft"},
 146         {Opt_hard, "hard"},
 147         {Opt_intr, "intr"},
 148         {Opt_nointr, "nointr"},
 149         {Opt_posix, "posix"},
 150         {Opt_noposix, "noposix"},
 151         {Opt_cto, "cto"},
 152         {Opt_nocto, "nocto"},
 153         {Opt_ac, "ac"},
 154         {Opt_noac, "noac"},
 155         {Opt_lock, "lock"},
 156         {Opt_nolock, "nolock"},
 157         {Opt_v2, "nfsvers=2"},
 158         {Opt_v2, "v2"},
 159         {Opt_v3, "nfsvers=3"},
 160         {Opt_v3, "v3"},
 161         {Opt_udp, "proto=udp"},
 162         {Opt_udp, "udp"},
 163         {Opt_tcp, "proto=tcp"},
 164         {Opt_tcp, "tcp"},
 165         {Opt_acl, "acl"},
 166         {Opt_noacl, "noacl"},
 167         {Opt_err, NULL}
 168
 169 };
 170
 171 /*
 172  *  Parse option string.
 173  */
 174
 175 static int __init root_nfs_parse(char *name, char *buf)
 176 {
 177
 178         char *p;
 179         substring_t args[MAX_OPT_ARGS];
 180         int option;
 181
 182         if (!name)
 183                 return 1;
 184
 185         /* Set the NFS remote path */
 186         p = strsep(&name, ",");
 187         if (p[0] != '\0' && strcmp(p, "default") != 0)
 188                 strlcpy(buf, p, NFS_MAXPATHLEN);
 189
 190         while ((p = strsep (&name, ",")) != NULL) {
 191                 int token;
 192                 if (!*p)
 193                         continue;
 194                 token = match_token(p, tokens, args);
 195
 196                 /* %u tokens only. Beware if you add new tokens! */
 197                 if (token < Opt_soft && match_int(&args[0], &option))
 198                         return 0;
 199                 switch (token) {
 200                         case Opt_port:
 201                                 nfs_port = option;
 202                                 break;
 203                         case Opt_rsize:
 204                                 nfs_data.rsize = option;
 205                                 break;
 206                         case Opt_wsize:
 207                                 nfs_data.wsize = option;
 208                                 break;
 209                         case Opt_timeo:
 210                                 nfs_data.timeo = option;
 211                                 break;
 212                         case Opt_retrans:
 213                                 nfs_data.retrans = option;
 214                                 break;
 215                         case Opt_acregmin:
 216                                 nfs_data.acregmin = option;
 217                                 break;
 218                         case Opt_acregmax:
 219                                 nfs_data.acregmax = option;
 220                                 break;
 221                         case Opt_acdirmin:
 222                                 nfs_data.acdirmin = option;
 223                                 break;
 224                         case Opt_acdirmax:
 225                                 nfs_data.acdirmax = option;
 226                                 break;
 227                         case Opt_soft:
 228                                 nfs_data.flags |= NFS_MOUNT_SOFT;
 229                                 break;
 230                         case Opt_hard:
 231                                 nfs_data.flags &= ~NFS_MOUNT_SOFT;
 232                                 break;
 233                         case Opt_intr:
 234                         case Opt_nointr:
 235                                 break;
 236                         case Opt_posix:
 237                                 nfs_data.flags |= NFS_MOUNT_POSIX;
 238                                 break;
 239                         case Opt_noposix:
 240                                 nfs_data.flags &= ~NFS_MOUNT_POSIX;
 241                                 break;
 242                         case Opt_cto:
 243                                 nfs_data.flags &= ~NFS_MOUNT_NOCTO;
 244                                 break;
 245                         case Opt_nocto:
 246                                 nfs_data.flags |= NFS_MOUNT_NOCTO;
 247                                 break;
 248                         case Opt_ac:
 249                                 nfs_data.flags &= ~NFS_MOUNT_NOAC;
 250                                 break;
 251                         case Opt_noac:
 252                                 nfs_data.flags |= NFS_MOUNT_NOAC;
 253                                 break;
 254                         case Opt_lock:
 255                                 nfs_data.flags &= ~NFS_MOUNT_NONLM;
 256                                 break;
 257                         case Opt_nolock:
 258                                 nfs_data.flags |= NFS_MOUNT_NONLM;
 259                                 break;
 260                         case Opt_v2:
 261                                 nfs_data.flags &= ~NFS_MOUNT_VER3;
 262                                 break;
 263                         case Opt_v3:
 264                                 nfs_data.flags |= NFS_MOUNT_VER3;
 265                                 break;
 266                         case Opt_udp:
 267                                 nfs_data.flags &= ~NFS_MOUNT_TCP;
 268                                 break;
 269                         case Opt_tcp:
 270                                 nfs_data.flags |= NFS_MOUNT_TCP;
 271                                 break;
 272                         case Opt_acl:
 273                                 nfs_data.flags &= ~NFS_MOUNT_NOACL;
 274                                 break;
 275                         case Opt_noacl:
 276                                 nfs_data.flags |= NFS_MOUNT_NOACL;
 277                                 break;
 278                         default:
 279                                 printk(KERN_WARNING "Root-NFS: unknown "
 280                                         "option: %s\n", p);
 281                                 return 0;
 282                 }
 283         }
 284
 285         return 1;
 286 }
 287
 288 /*
 289  *  Prepare the NFS data structure and parse all options.
 290  */
 291 static int __init root_nfs_name(char *name)
 292 {
 293         static char buf[NFS_MAXPATHLEN] __initdata;
 294         char *cp;
 295
 296         /* Set some default values */
 297         memset(&nfs_data, 0, sizeof(nfs_data));
 298         nfs_port          = -1;
 299         nfs_data.version  = NFS_MOUNT_VERSION;
 300         nfs_data.flags    = NFS_MOUNT_NONLM;    /* No lockd in nfs root yet */
 301         nfs_data.rsize    = NFS_DEF_FILE_IO_SIZE;
 302         nfs_data.wsize    = NFS_DEF_FILE_IO_SIZE;
 303         nfs_data.acregmin = NFS_DEF_ACREGMIN;
 304         nfs_data.acregmax = NFS_DEF_ACREGMAX;
 305         nfs_data.acdirmin = NFS_DEF_ACDIRMIN;
 306         nfs_data.acdirmax = NFS_DEF_ACDIRMAX;
 307         strcpy(buf, NFS_ROOT);
 308
 309         /* Process options received from the remote server */
 310         root_nfs_parse(root_server_path, buf);
 311
 312         /* Override them by options set on kernel command-line */
 313         root_nfs_parse(name, buf);
 314
 315         cp = utsname()->nodename;
 316         if (strlen(buf) + strlen(cp) > NFS_MAXPATHLEN) {
 317                 printk(KERN_ERR "Root-NFS: Pathname for remote directory too long.\n");
 318                 return -1;
 319         }
 320         sprintf(nfs_export_path, buf, cp);
 321
 322         return 1;
 323 }
 324
 325
 326 /*
 327  *  Get NFS server address.
 328  */
 329 static int __init root_nfs_addr(void)
 330 {
 331         if ((servaddr = root_server_addr) == htonl(INADDR_NONE)) {
 332                 printk(KERN_ERR "Root-NFS: No NFS server available, giving up.\n");
 333                 return -1;
 334         }
 335
 336         snprintf(nfs_data.hostname, sizeof(nfs_data.hostname),
 337                  "%pI4", &servaddr);
 338         return 0;
 339 }
 340
 341 /*
 342  *  Tell the user what's going on.
 343  */
 344 #ifdef NFSROOT_DEBUG
 345 static void __init root_nfs_print(void)
 346 {
 347         printk(KERN_NOTICE "Root-NFS: Mounting %s on server %s as root\n",
 348                 nfs_export_path, nfs_data.hostname);
 349         printk(KERN_NOTICE "Root-NFS:     rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
 350                 nfs_data.rsize, nfs_data.wsize, nfs_data.timeo, nfs_data.retrans);
 351         printk(KERN_NOTICE "Root-NFS:     acreg (min,max) = (%d,%d), acdir (min,max) = (%d,%d)\n",
 352                 nfs_data.acregmin, nfs_data.acregmax,
 353                 nfs_data.acdirmin, nfs_data.acdirmax);
 354         printk(KERN_NOTICE "Root-NFS:     nfsd port = %d, mountd port = %d, flags = %08x\n",
 355                 nfs_port, mount_port, nfs_data.flags);
 356 }
 357 #endif
 358
 359
 360 static int __init root_nfs_init(void)
 361 {
 362 #ifdef NFSROOT_DEBUG
 363         nfs_debug |= NFSDBG_ROOT;
 364 #endif
 365
 366         /*
 367          * Decode the root directory path name and NFS options from
 368          * the kernel command line. This has to go here in order to
 369          * be able to use the client IP address for the remote root
 370          * directory (necessary for pure RARP booting).
 371          */
 372         if (root_nfs_name(nfs_root_name) < 0 ||
 373             root_nfs_addr() < 0)
 374                 return -1;
 375
 376 #ifdef NFSROOT_DEBUG
 377         root_nfs_print();
 378 #endif
 379
 380         return 0;
 381 }
 382
 383
 384 /*
 385  *  Parse NFS server and directory information passed on the kernel
 386  *  command line.
 387  */
 388 static int __init nfs_root_setup(char *line)
 389 {
 390         ROOT_DEV = Root_NFS;
 391         if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
 392                 strlcpy(nfs_root_name, line, sizeof(nfs_root_name));
 393         } else {
 394                 int n = strlen(line) + sizeof(NFS_ROOT) - 1;
 395                 if (n >= sizeof(nfs_root_name))
 396                         line[sizeof(nfs_root_name) - sizeof(NFS_ROOT) - 2] = '\0';
 397                 sprintf(nfs_root_name, NFS_ROOT, line);
 398         }
 399         root_server_addr = root_nfs_parse_addr(nfs_root_name);
 400         return 1;
 401 }
 402
 403 __setup("nfsroot=", nfs_root_setup);
 404
 405 /***************************************************************************
 406
 407                Routines to actually mount the root directory
 408
 409  ***************************************************************************/
 410
 411 /*
 412  *  Construct sockaddr_in from address and port number.
 413  */
 414 static inline void
 415 set_sockaddr(struct sockaddr_in *sin, __be32 addr, __be16 port)
 416 {
 417         sin->sin_family = AF_INET;
 418         sin->sin_addr.s_addr = addr;
 419         sin->sin_port = port;
 420 }
 421
 422 /*
 423  *  Query server portmapper for the port of a daemon program.
 424  */
 425 static int __init root_nfs_getport(int program, int version, int proto)
 426 {
 427         struct sockaddr_in sin;
 428
 429         printk(KERN_NOTICE "Looking up port of RPC %d/%d on %pI4\n",
 430                 program, version, &servaddr);
 431         set_sockaddr(&sin, servaddr, 0);
 432         return rpcb_getport_sync(&sin, program, version, proto);
 433 }
 434
 435
 436 /*
 437  *  Use portmapper to find mountd and nfsd port numbers if not overriden
 438  *  by the user. Use defaults if portmapper is not available.
 439  *  XXX: Is there any nfs server with no portmapper?
 440  */
 441 static int __init root_nfs_ports(void)
 442 {
 443         int port;
 444         int nfsd_ver, mountd_ver;
 445         int nfsd_port, mountd_port;
 446         int proto;
 447
 448         if (nfs_data.flags & NFS_MOUNT_VER3) {
 449                 nfsd_ver = NFS3_VERSION;
 450                 mountd_ver = NFS_MNT3_VERSION;
 451                 nfsd_port = NFS_PORT;
 452                 mountd_port = NFS_MNT_PORT;
 453         } else {
 454                 nfsd_ver = NFS2_VERSION;
 455                 mountd_ver = NFS_MNT_VERSION;
 456                 nfsd_port = NFS_PORT;
 457                 mountd_port = NFS_MNT_PORT;
 458         }
 459
 460         proto = (nfs_data.flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;
 461
 462         if (nfs_port < 0) {
 463                 if ((port = root_nfs_getport(NFS_PROGRAM, nfsd_ver, proto)) < 0) {
 464                         printk(KERN_ERR "Root-NFS: Unable to get nfsd port "
 465                                         "number from server, using default\n");
 466                         port = nfsd_port;
 467                 }
 468                 nfs_port = port;
 469                 dprintk("Root-NFS: Portmapper on server returned %d "
 470                         "as nfsd port\n", port);
 471         }
 472
 473         if ((port = root_nfs_getport(NFS_MNT_PROGRAM, mountd_ver, proto)) < 0) {
 474                 printk(KERN_ERR "Root-NFS: Unable to get mountd port "
 475                                 "number from server, using default\n");
 476                 port = mountd_port;
 477         }
 478         mount_port = port;
 479         dprintk("Root-NFS: mountd port is %d\n", port);
 480
 481         return 0;
 482 }
 483
 484
 485 /*
 486  *  Get a file handle from the server for the directory which is to be
 487  *  mounted.
 488  */
 489 static int __init root_nfs_get_handle(void)
 490 {
 491         struct sockaddr_in sin;
 492         unsigned int auth_flav_len = 0;
 493         struct nfs_mount_request request = {
 494                 .sap            = (struct sockaddr *)&sin,
 495                 .salen          = sizeof(sin),
 496                 .dirpath        = nfs_export_path,
 497                 .version        = (nfs_data.flags & NFS_MOUNT_VER3) ?
 498                                         NFS_MNT3_VERSION : NFS_MNT_VERSION,
 499                 .protocol       = (nfs_data.flags & NFS_MOUNT_TCP) ?
 500                                         XPRT_TRANSPORT_TCP : XPRT_TRANSPORT_UDP,
 501                 .auth_flav_len  = &auth_flav_len,
 502         };
 503         int status = -ENOMEM;
 504
 505         request.fh = nfs_alloc_fhandle();
 506         if (!request.fh)
 507                 goto out;
 508         set_sockaddr(&sin, servaddr, htons(mount_port));
 509         status = nfs_mount(&request);
 510         if (status < 0)
 511                 printk(KERN_ERR "Root-NFS: Server returned error %d "
 512                                 "while mounting %s\n", status, nfs_export_path);
 513         else {
 514                 nfs_data.root.size = request.fh->size;
 515                 memcpy(&nfs_data.root.data, request.fh->data, request.fh->size);
 516         }
 517         nfs_free_fhandle(request.fh);
 518 out:
 519         return status;
 520 }
 521
 522 /*
 523  *  Get the NFS port numbers and file handle, and return the prepared 'data'
 524  *  argument for mount() if everything went OK. Return NULL otherwise.
 525  */
 526 void * __init nfs_root_data(void)
 527 {
 528         if (root_nfs_init() < 0
 529          || root_nfs_ports() < 0
 530          || root_nfs_get_handle() < 0)
 531                 return NULL;
 532         set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, htons(nfs_port));
 533         return (void*)&nfs_data;
 534 }