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  */
  70
  71 #include <linux/config.h>
  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
  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 __u32 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 /*
 118  *  The following integer options are recognized
 119  */
 120 static struct nfs_int_opts {
 121         char *name;
 122         int  *val;
 123 } root_int_opts[] __initdata = {
 124         { "port",       &nfs_port },
 125         { "rsize",      &nfs_data.rsize },
 126         { "wsize",      &nfs_data.wsize },
 127         { "timeo",      &nfs_data.timeo },
 128         { "retrans",    &nfs_data.retrans },
 129         { "acregmin",   &nfs_data.acregmin },
 130         { "acregmax",   &nfs_data.acregmax },
 131         { "acdirmin",   &nfs_data.acdirmin },
 132         { "acdirmax",   &nfs_data.acdirmax },
 133         { NULL,         NULL }
 134 };
 135
 136
 137 /*
 138  *  And now the flag options
 139  */
 140 static struct nfs_bool_opts {
 141         char *name;
 142         int  and_mask;
 143         int  or_mask;
 144 } root_bool_opts[] __initdata = {
 145         { "soft",       ~NFS_MOUNT_SOFT,        NFS_MOUNT_SOFT },
 146         { "hard",       ~NFS_MOUNT_SOFT,        0 },
 147         { "intr",       ~NFS_MOUNT_INTR,        NFS_MOUNT_INTR },
 148         { "nointr",     ~NFS_MOUNT_INTR,        0 },
 149         { "posix",      ~NFS_MOUNT_POSIX,       NFS_MOUNT_POSIX },
 150         { "noposix",    ~NFS_MOUNT_POSIX,       0 },
 151         { "cto",        ~NFS_MOUNT_NOCTO,       0 },
 152         { "nocto",      ~NFS_MOUNT_NOCTO,       NFS_MOUNT_NOCTO },
 153         { "ac",         ~NFS_MOUNT_NOAC,        0 },
 154         { "noac",       ~NFS_MOUNT_NOAC,        NFS_MOUNT_NOAC },
 155         { "lock",       ~NFS_MOUNT_NONLM,       0 },
 156         { "nolock",     ~NFS_MOUNT_NONLM,       NFS_MOUNT_NONLM },
 157 #ifdef CONFIG_NFS_V3
 158         { "v2",         ~NFS_MOUNT_VER3,        0 },
 159         { "v3",         ~NFS_MOUNT_VER3,        NFS_MOUNT_VER3 },
 160 #endif
 161         { "udp",        ~NFS_MOUNT_TCP,         0 },
 162         { "tcp",        ~NFS_MOUNT_TCP,         NFS_MOUNT_TCP },
 163         { "broken_suid",~NFS_MOUNT_BROKEN_SUID, NFS_MOUNT_BROKEN_SUID },
 164         { NULL,         0,                      0 }
 165 };
 166
 167
 168 /*
 169  *  Extract IP address from the parameter string if needed. Note that we
 170  *  need to have root_server_addr set _before_ IPConfig gets called as it
 171  *  can override it.
 172  */
 173 static void __init root_nfs_parse_addr(char *name)
 174 {
 175         int octets = 0;
 176         char *cp, *cq;
 177
 178         cp = cq = name;
 179         while (octets < 4) {
 180                 while (*cp >= '0' && *cp <= '9')
 181                         cp++;
 182                 if (cp == cq || cp - cq > 3)
 183                         break;
 184                 if (*cp == '.' || octets == 3)
 185                         octets++;
 186                 if (octets < 4)
 187                         cp++;
 188                 cq = cp;
 189         }
 190         if (octets == 4 && (*cp == ':' || *cp == '\0')) {
 191                 if (*cp == ':')
 192                         *cp++ = '\0';
 193                 root_server_addr = in_aton(name);
 194                 strcpy(name, cp);
 195         }
 196 }
 197
 198
 199 /*
 200  *  Parse option string.
 201  */
 202 static void __init root_nfs_parse(char *name, char *buf)
 203 {
 204         char *options, *val, *cp;
 205
 206         if ((options = strchr(name, ','))) {
 207                 *options++ = 0;
 208                 while ((cp = strsep(&options, ",")) != NULL) {
 209                         if (!*cp)
 210                                 continue;
 211                         if ((val = strchr(cp, '='))) {
 212                                 struct nfs_int_opts *opts = root_int_opts;
 213                                 *val++ = '\0';
 214                                 while (opts->name && strcmp(opts->name, cp))
 215                                         opts++;
 216                                 if (opts->name)
 217                                         *(opts->val) = (int) simple_strtoul(val, NULL, 10);
 218                         } else {
 219                                 struct nfs_bool_opts *opts = root_bool_opts;
 220                                 while (opts->name && strcmp(opts->name, cp))
 221                                         opts++;
 222                                 if (opts->name) {
 223                                         nfs_data.flags &= opts->and_mask;
 224                                         nfs_data.flags |= opts->or_mask;
 225                                 }
 226                         }
 227                 }
 228         }
 229         if (name[0] && strcmp(name, "default"))
 230                 strlcpy(buf, name, NFS_MAXPATHLEN);
 231 }
 232
 233
 234 /*
 235  *  Prepare the NFS data structure and parse all options.
 236  */
 237 static int __init root_nfs_name(char *name)
 238 {
 239         char buf[NFS_MAXPATHLEN];
 240         char *cp;
 241
 242         /* Set some default values */
 243         memset(&nfs_data, 0, sizeof(nfs_data));
 244         nfs_port          = -1;
 245         nfs_data.version  = NFS_MOUNT_VERSION;
 246         nfs_data.flags    = NFS_MOUNT_NONLM;    /* No lockd in nfs root yet */
 247         nfs_data.rsize    = NFS_DEF_FILE_IO_BUFFER_SIZE;
 248         nfs_data.wsize    = NFS_DEF_FILE_IO_BUFFER_SIZE;
 249         nfs_data.bsize    = 0;
 250         nfs_data.timeo    = 7;
 251         nfs_data.retrans  = 3;
 252         nfs_data.acregmin = 3;
 253         nfs_data.acregmax = 60;
 254         nfs_data.acdirmin = 30;
 255         nfs_data.acdirmax = 60;
 256         strcpy(buf, NFS_ROOT);
 257
 258         /* Process options received from the remote server */
 259         root_nfs_parse(root_server_path, buf);
 260
 261         /* Override them by options set on kernel command-line */
 262         root_nfs_parse(name, buf);
 263
 264         cp = system_utsname.nodename;
 265         if (strlen(buf) + strlen(cp) > NFS_MAXPATHLEN) {
 266                 printk(KERN_ERR "Root-NFS: Pathname for remote directory too long.\n");
 267                 return -1;
 268         }
 269         sprintf(nfs_path, buf, cp);
 270
 271         return 1;
 272 }
 273
 274
 275 /*
 276  *  Get NFS server address.
 277  */
 278 static int __init root_nfs_addr(void)
 279 {
 280         if ((servaddr = root_server_addr) == INADDR_NONE) {
 281                 printk(KERN_ERR "Root-NFS: No NFS server available, giving up.\n");
 282                 return -1;
 283         }
 284
 285         snprintf(nfs_data.hostname, sizeof(nfs_data.hostname),
 286                  "%u.%u.%u.%u", NIPQUAD(servaddr));
 287         return 0;
 288 }
 289
 290 /*
 291  *  Tell the user what's going on.
 292  */
 293 #ifdef NFSROOT_DEBUG
 294 static void __init root_nfs_print(void)
 295 {
 296         printk(KERN_NOTICE "Root-NFS: Mounting %s on server %s as root\n",
 297                 nfs_path, nfs_data.hostname);
 298         printk(KERN_NOTICE "Root-NFS:     rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
 299                 nfs_data.rsize, nfs_data.wsize, nfs_data.timeo, nfs_data.retrans);
 300         printk(KERN_NOTICE "Root-NFS:     acreg (min,max) = (%d,%d), acdir (min,max) = (%d,%d)\n",
 301                 nfs_data.acregmin, nfs_data.acregmax,
 302                 nfs_data.acdirmin, nfs_data.acdirmax);
 303         printk(KERN_NOTICE "Root-NFS:     nfsd port = %d, mountd port = %d, flags = %08x\n",
 304                 nfs_port, mount_port, nfs_data.flags);
 305 }
 306 #endif
 307
 308
 309 int __init root_nfs_init(void)
 310 {
 311 #ifdef NFSROOT_DEBUG
 312         nfs_debug |= NFSDBG_ROOT;
 313 #endif
 314
 315         /*
 316          * Decode the root directory path name and NFS options from
 317          * the kernel command line. This has to go here in order to
 318          * be able to use the client IP address for the remote root
 319          * directory (necessary for pure RARP booting).
 320          */
 321         if (root_nfs_name(nfs_root_name) < 0 ||
 322             root_nfs_addr() < 0)
 323                 return -1;
 324
 325 #ifdef NFSROOT_DEBUG
 326         root_nfs_print();
 327 #endif
 328
 329         return 0;
 330 }
 331
 332
 333 /*
 334  *  Parse NFS server and directory information passed on the kernel
 335  *  command line.
 336  */
 337 int __init nfs_root_setup(char *line)
 338 {
 339         ROOT_DEV = Root_NFS;
 340         if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
 341                 strlcpy(nfs_root_name, line, sizeof(nfs_root_name));
 342         } else {
 343                 int n = strlen(line) + strlen(NFS_ROOT);
 344                 if (n >= sizeof(nfs_root_name))
 345                         line[sizeof(nfs_root_name) - strlen(NFS_ROOT) - 1] = '\0';
 346                 sprintf(nfs_root_name, NFS_ROOT, line);
 347         }
 348         root_nfs_parse_addr(nfs_root_name);
 349         return 1;
 350 }
 351
 352 __setup("nfsroot=", nfs_root_setup);
 353
 354 /***************************************************************************
 355
 356                Routines to actually mount the root directory
 357
 358  ***************************************************************************/
 359
 360 /*
 361  *  Construct sockaddr_in from address and port number.
 362  */
 363 static inline void
 364 set_sockaddr(struct sockaddr_in *sin, __u32 addr, __u16 port)
 365 {
 366         sin->sin_family = AF_INET;
 367         sin->sin_addr.s_addr = addr;
 368         sin->sin_port = port;
 369 }
 370
 371 /*
 372  *  Query server portmapper for the port of a daemon program.
 373  */
 374 static int __init root_nfs_getport(int program, int version, int proto)
 375 {
 376         struct sockaddr_in sin;
 377
 378         printk(KERN_NOTICE "Looking up port of RPC %d/%d on %u.%u.%u.%u\n",
 379                 program, version, NIPQUAD(servaddr));
 380         set_sockaddr(&sin, servaddr, 0);
 381         return rpc_getport_external(&sin, program, version, proto);
 382 }
 383
 384
 385 /*
 386  *  Use portmapper to find mountd and nfsd port numbers if not overriden
 387  *  by the user. Use defaults if portmapper is not available.
 388  *  XXX: Is there any nfs server with no portmapper?
 389  */
 390 static int __init root_nfs_ports(void)
 391 {
 392         int port;
 393         int nfsd_ver, mountd_ver;
 394         int nfsd_port, mountd_port;
 395         int proto;
 396
 397         if (nfs_data.flags & NFS_MOUNT_VER3) {
 398                 nfsd_ver = NFS3_VERSION;
 399                 mountd_ver = NFS_MNT3_VERSION;
 400                 nfsd_port = NFS_PORT;
 401                 mountd_port = NFS_MNT_PORT;
 402         } else {
 403                 nfsd_ver = NFS2_VERSION;
 404                 mountd_ver = NFS_MNT_VERSION;
 405                 nfsd_port = NFS_PORT;
 406                 mountd_port = NFS_MNT_PORT;
 407         }
 408
 409         proto = (nfs_data.flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;
 410
 411         if (nfs_port < 0) {
 412                 if ((port = root_nfs_getport(NFS_PROGRAM, nfsd_ver, proto)) < 0) {
 413                         printk(KERN_ERR "Root-NFS: Unable to get nfsd port "
 414                                         "number from server, using default\n");
 415                         port = nfsd_port;
 416                 }
 417                 nfs_port = htons(port);
 418                 dprintk("Root-NFS: Portmapper on server returned %d "
 419                         "as nfsd port\n", port);
 420         }
 421
 422         if ((port = root_nfs_getport(NFS_MNT_PROGRAM, mountd_ver, proto)) < 0) {
 423                 printk(KERN_ERR "Root-NFS: Unable to get mountd port "
 424                                 "number from server, using default\n");
 425                 port = mountd_port;
 426         }
 427         mount_port = htons(port);
 428         dprintk("Root-NFS: mountd port is %d\n", port);
 429
 430         return 0;
 431 }
 432
 433
 434 /*
 435  *  Get a file handle from the server for the directory which is to be
 436  *  mounted.
 437  */
 438 static int __init root_nfs_get_handle(void)
 439 {
 440         struct nfs_fh fh;
 441         struct sockaddr_in sin;
 442         int status;
 443         int protocol = (nfs_data.flags & NFS_MOUNT_TCP) ?
 444                                         IPPROTO_TCP : IPPROTO_UDP;
 445         int version = (nfs_data.flags & NFS_MOUNT_VER3) ?
 446                                         NFS_MNT3_VERSION : NFS_MNT_VERSION;
 447
 448         set_sockaddr(&sin, servaddr, mount_port);
 449         status = nfsroot_mount(&sin, nfs_path, &fh, version, protocol);
 450         if (status < 0)
 451                 printk(KERN_ERR "Root-NFS: Server returned error %d "
 452                                 "while mounting %s\n", status, nfs_path);
 453         else {
 454                 nfs_data.root.size = fh.size;
 455                 memcpy(nfs_data.root.data, fh.data, fh.size);
 456         }
 457
 458         return status;
 459 }
 460
 461 /*
 462  *  Get the NFS port numbers and file handle, and return the prepared 'data'
 463  *  argument for mount() if everything went OK. Return NULL otherwise.
 464  */
 465 void * __init nfs_root_data(void)
 466 {
 467         if (root_nfs_init() < 0
 468          || root_nfs_ports() < 0
 469          || root_nfs_get_handle() < 0)
 470                 return NULL;
 471         set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, nfs_port);
 472         return (void*)&nfs_data;
 473 }