fs/lockd/svc.c

   1 /*
   2  * linux/fs/lockd/svc.c
   3  *
   4  * This is the central lockd service.
   5  *
   6  * FIXME: Separate the lockd NFS server functionality from the lockd NFS
   7  *        client functionality. Oh why didn't Sun create two separate
   8  *        services in the first place?
   9  *
  10  * Authors:     Olaf Kirch (okir@monad.swb.de)
  11  *
  12  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/sysctl.h>
  18 #include <linux/moduleparam.h>
  19
  20 #include <linux/sched.h>
  21 #include <linux/errno.h>
  22 #include <linux/in.h>
  23 #include <linux/uio.h>
  24 #include <linux/slab.h>
  25 #include <linux/smp.h>
  26 #include <linux/smp_lock.h>
  27 #include <linux/mutex.h>
  28 #include <linux/freezer.h>
  29
  30 #include <linux/sunrpc/types.h>
  31 #include <linux/sunrpc/stats.h>
  32 #include <linux/sunrpc/clnt.h>
  33 #include <linux/sunrpc/svc.h>
  34 #include <linux/sunrpc/svcsock.h>
  35 #include <net/ip.h>
  36 #include <linux/lockd/lockd.h>
  37 #include <linux/lockd/sm_inter.h>
  38 #include <linux/nfs.h>
  39
  40 #define NLMDBG_FACILITY         NLMDBG_SVC
  41 #define LOCKD_BUFSIZE           (1024 + NLMSVC_XDRSIZE)
  42 #define ALLOWED_SIGS            (sigmask(SIGKILL))
  43
  44 static struct svc_program       nlmsvc_program;
  45
  46 struct nlmsvc_binding *         nlmsvc_ops;
  47 EXPORT_SYMBOL(nlmsvc_ops);
  48
  49 static DEFINE_MUTEX(nlmsvc_mutex);
  50 static unsigned int             nlmsvc_users;
  51 static pid_t                    nlmsvc_pid;
  52 static struct svc_serv          *nlmsvc_serv;
  53 int                             nlmsvc_grace_period;
  54 unsigned long                   nlmsvc_timeout;
  55
  56 static DECLARE_COMPLETION(lockd_start_done);
  57 static DECLARE_WAIT_QUEUE_HEAD(lockd_exit);
  58
  59 /*
  60  * These can be set at insmod time (useful for NFS as root filesystem),
  61  * and also changed through the sysctl interface.  -- Jamie Lokier, Aug 2003
  62  */
  63 static unsigned long            nlm_grace_period;
  64 static unsigned long            nlm_timeout = LOCKD_DFLT_TIMEO;
  65 static int                      nlm_udpport, nlm_tcpport;
  66 int                             nsm_use_hostnames = 0;
  67
  68 /*
  69  * Constants needed for the sysctl interface.
  70  */
  71 static const unsigned long      nlm_grace_period_min = 0;
  72 static const unsigned long      nlm_grace_period_max = 240;
  73 static const unsigned long      nlm_timeout_min = 3;
  74 static const unsigned long      nlm_timeout_max = 20;
  75 static const int                nlm_port_min = 0, nlm_port_max = 65535;
  76
  77 static struct ctl_table_header * nlm_sysctl_table;
  78
  79 static unsigned long get_lockd_grace_period(void)
  80 {
  81         /* Note: nlm_timeout should always be nonzero */
  82         if (nlm_grace_period)
  83                 return roundup(nlm_grace_period, nlm_timeout) * HZ;
  84         else
  85                 return nlm_timeout * 5 * HZ;
  86 }
  87
  88 unsigned long get_nfs_grace_period(void)
  89 {
  90         unsigned long lockdgrace = get_lockd_grace_period();
  91         unsigned long nfsdgrace = 0;
  92
  93         if (nlmsvc_ops)
  94                 nfsdgrace = nlmsvc_ops->get_grace_period();
  95
  96         return max(lockdgrace, nfsdgrace);
  97 }
  98 EXPORT_SYMBOL(get_nfs_grace_period);
  99
 100 static unsigned long set_grace_period(void)
 101 {
 102         nlmsvc_grace_period = 1;
 103         return get_nfs_grace_period() + jiffies;
 104 }
 105
 106 static inline void clear_grace_period(void)
 107 {
 108         nlmsvc_grace_period = 0;
 109 }
 110
 111 /*
 112  * This is the lockd kernel thread
 113  */
 114 static void
 115 lockd(struct svc_rqst *rqstp)
 116 {
 117         int             err = 0;
 118         unsigned long grace_period_expire;
 119
 120         /* Lock module and set up kernel thread */
 121         /* lockd_up is waiting for us to startup, so will
 122          * be holding a reference to this module, so it
 123          * is safe to just claim another reference
 124          */
 125         __module_get(THIS_MODULE);
 126         lock_kernel();
 127
 128         /*
 129          * Let our maker know we're running.
 130          */
 131         nlmsvc_pid = current->pid;
 132         nlmsvc_serv = rqstp->rq_server;
 133         complete(&lockd_start_done);
 134
 135         daemonize("lockd");
 136         set_freezable();
 137
 138         /* Process request with signals blocked, but allow SIGKILL.  */
 139         allow_signal(SIGKILL);
 140
 141         dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
 142
 143         if (!nlm_timeout)
 144                 nlm_timeout = LOCKD_DFLT_TIMEO;
 145         nlmsvc_timeout = nlm_timeout * HZ;
 146
 147         grace_period_expire = set_grace_period();
 148
 149         /*
 150          * The main request loop. We don't terminate until the last
 151          * NFS mount or NFS daemon has gone away, and we've been sent a
 152          * signal, or else another process has taken over our job.
 153          */
 154         while ((nlmsvc_users || !signalled()) && nlmsvc_pid == current->pid) {
 155                 long timeout = MAX_SCHEDULE_TIMEOUT;
 156                 char buf[RPC_MAX_ADDRBUFLEN];
 157
 158                 if (signalled()) {
 159                         flush_signals(current);
 160                         if (nlmsvc_ops) {
 161                                 nlmsvc_invalidate_all();
 162                                 grace_period_expire = set_grace_period();
 163                         }
 164                 }
 165
 166                 /*
 167                  * Retry any blocked locks that have been notified by
 168                  * the VFS. Don't do this during grace period.
 169                  * (Theoretically, there shouldn't even be blocked locks
 170                  * during grace period).
 171                  */
 172                 if (!nlmsvc_grace_period) {
 173                         timeout = nlmsvc_retry_blocked();
 174                 } else if (time_before(grace_period_expire, jiffies))
 175                         clear_grace_period();
 176
 177                 /*
 178                  * Find a socket with data available and call its
 179                  * recvfrom routine.
 180                  */
 181                 err = svc_recv(rqstp, timeout);
 182                 if (err == -EAGAIN || err == -EINTR)
 183                         continue;
 184                 if (err < 0) {
 185                         printk(KERN_WARNING
 186                                "lockd: terminating on error %d\n",
 187                                -err);
 188                         break;
 189                 }
 190
 191                 dprintk("lockd: request from %s\n",
 192                                 svc_print_addr(rqstp, buf, sizeof(buf)));
 193
 194                 svc_process(rqstp);
 195         }
 196
 197         flush_signals(current);
 198
 199         /*
 200          * Check whether there's a new lockd process before
 201          * shutting down the hosts and clearing the slot.
 202          */
 203         if (!nlmsvc_pid || current->pid == nlmsvc_pid) {
 204                 if (nlmsvc_ops)
 205                         nlmsvc_invalidate_all();
 206                 nlm_shutdown_hosts();
 207                 nlmsvc_pid = 0;
 208                 nlmsvc_serv = NULL;
 209         } else
 210                 printk(KERN_DEBUG
 211                         "lockd: new process, skipping host shutdown\n");
 212         wake_up(&lockd_exit);
 213
 214         /* Exit the RPC thread */
 215         svc_exit_thread(rqstp);
 216
 217         /* Release module */
 218         unlock_kernel();
 219         module_put_and_exit(0);
 220 }
 221
 222 static int find_xprt(struct svc_serv *serv, char *proto)
 223 {
 224         struct svc_sock *svsk;
 225         int found = 0;
 226         list_for_each_entry(svsk, &serv->sv_permsocks, sk_list)
 227                 if (strcmp(svsk->sk_xprt.xpt_class->xcl_name, proto) == 0) {
 228                         found = 1;
 229                         break;
 230                 }
 231         return found;
 232 }
 233
 234 /*
 235  * Make any sockets that are needed but not present.
 236  * If nlm_udpport or nlm_tcpport were set as module
 237  * options, make those sockets unconditionally
 238  */
 239 static int make_socks(struct svc_serv *serv, int proto)
 240 {
 241         static int warned;
 242         int err = 0;
 243
 244         if (proto == IPPROTO_UDP || nlm_udpport)
 245                 if (!find_xprt(serv, "udp"))
 246                         err = svc_create_xprt(serv, "udp", nlm_udpport,
 247                                               SVC_SOCK_DEFAULTS);
 248         if (err >= 0 && (proto == IPPROTO_TCP || nlm_tcpport))
 249                 if (!find_xprt(serv, "tcp"))
 250                         err = svc_create_xprt(serv, "tcp", nlm_tcpport,
 251                                               SVC_SOCK_DEFAULTS);
 252
 253         if (err >= 0) {
 254                 warned = 0;
 255                 err = 0;
 256         } else if (warned++ == 0)
 257                 printk(KERN_WARNING
 258                        "lockd_up: makesock failed, error=%d\n", err);
 259         return err;
 260 }
 261
 262 /*
 263  * Bring up the lockd process if it's not already up.
 264  */
 265 int
 266 lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
 267 {
 268         struct svc_serv *       serv;
 269         int                     error = 0;
 270
 271         mutex_lock(&nlmsvc_mutex);
 272         /*
 273          * Check whether we're already up and running.
 274          */
 275         if (nlmsvc_pid) {
 276                 if (proto)
 277                         error = make_socks(nlmsvc_serv, proto);
 278                 goto out;
 279         }
 280
 281         /*
 282          * Sanity check: if there's no pid,
 283          * we should be the first user ...
 284          */
 285         if (nlmsvc_users)
 286                 printk(KERN_WARNING
 287                         "lockd_up: no pid, %d users??\n", nlmsvc_users);
 288
 289         error = -ENOMEM;
 290         serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
 291         if (!serv) {
 292                 printk(KERN_WARNING "lockd_up: create service failed\n");
 293                 goto out;
 294         }
 295
 296         if ((error = make_socks(serv, proto)) < 0)
 297                 goto destroy_and_out;
 298
 299         /*
 300          * Create the kernel thread and wait for it to start.
 301          */
 302         error = svc_create_thread(lockd, serv);
 303         if (error) {
 304                 printk(KERN_WARNING
 305                         "lockd_up: create thread failed, error=%d\n", error);
 306                 goto destroy_and_out;
 307         }
 308         wait_for_completion(&lockd_start_done);
 309
 310         /*
 311          * Note: svc_serv structures have an initial use count of 1,
 312          * so we exit through here on both success and failure.
 313          */
 314 destroy_and_out:
 315         svc_destroy(serv);
 316 out:
 317         if (!error)
 318                 nlmsvc_users++;
 319         mutex_unlock(&nlmsvc_mutex);
 320         return error;
 321 }
 322 EXPORT_SYMBOL(lockd_up);
 323
 324 /*
 325  * Decrement the user count and bring down lockd if we're the last.
 326  */
 327 void
 328 lockd_down(void)
 329 {
 330         static int warned;
 331
 332         mutex_lock(&nlmsvc_mutex);
 333         if (nlmsvc_users) {
 334                 if (--nlmsvc_users)
 335                         goto out;
 336         } else
 337                 printk(KERN_WARNING "lockd_down: no users! pid=%d\n", nlmsvc_pid);
 338
 339         if (!nlmsvc_pid) {
 340                 if (warned++ == 0)
 341                         printk(KERN_WARNING "lockd_down: no lockd running.\n");
 342                 goto out;
 343         }
 344         warned = 0;
 345
 346         kill_proc(nlmsvc_pid, SIGKILL, 1);
 347         /*
 348          * Wait for the lockd process to exit, but since we're holding
 349          * the lockd semaphore, we can't wait around forever ...
 350          */
 351         clear_thread_flag(TIF_SIGPENDING);
 352         interruptible_sleep_on_timeout(&lockd_exit, HZ);
 353         if (nlmsvc_pid) {
 354                 printk(KERN_WARNING
 355                         "lockd_down: lockd failed to exit, clearing pid\n");
 356                 nlmsvc_pid = 0;
 357         }
 358         spin_lock_irq(&current->sighand->siglock);
 359         recalc_sigpending();
 360         spin_unlock_irq(&current->sighand->siglock);
 361 out:
 362         mutex_unlock(&nlmsvc_mutex);
 363 }
 364 EXPORT_SYMBOL(lockd_down);
 365
 366 /*
 367  * Sysctl parameters (same as module parameters, different interface).
 368  */
 369
 370 static ctl_table nlm_sysctls[] = {
 371         {
 372                 .ctl_name       = CTL_UNNUMBERED,
 373                 .procname       = "nlm_grace_period",
 374                 .data           = &nlm_grace_period,
 375                 .maxlen         = sizeof(unsigned long),
 376                 .mode           = 0644,
 377                 .proc_handler   = &proc_doulongvec_minmax,
 378                 .extra1         = (unsigned long *) &nlm_grace_period_min,
 379                 .extra2         = (unsigned long *) &nlm_grace_period_max,
 380         },
 381         {
 382                 .ctl_name       = CTL_UNNUMBERED,
 383                 .procname       = "nlm_timeout",
 384                 .data           = &nlm_timeout,
 385                 .maxlen         = sizeof(unsigned long),
 386                 .mode           = 0644,
 387                 .proc_handler   = &proc_doulongvec_minmax,
 388                 .extra1         = (unsigned long *) &nlm_timeout_min,
 389                 .extra2         = (unsigned long *) &nlm_timeout_max,
 390         },
 391         {
 392                 .ctl_name       = CTL_UNNUMBERED,
 393                 .procname       = "nlm_udpport",
 394                 .data           = &nlm_udpport,
 395                 .maxlen         = sizeof(int),
 396                 .mode           = 0644,
 397                 .proc_handler   = &proc_dointvec_minmax,
 398                 .extra1         = (int *) &nlm_port_min,
 399                 .extra2         = (int *) &nlm_port_max,
 400         },
 401         {
 402                 .ctl_name       = CTL_UNNUMBERED,
 403                 .procname       = "nlm_tcpport",
 404                 .data           = &nlm_tcpport,
 405                 .maxlen         = sizeof(int),
 406                 .mode           = 0644,
 407                 .proc_handler   = &proc_dointvec_minmax,
 408                 .extra1         = (int *) &nlm_port_min,
 409                 .extra2         = (int *) &nlm_port_max,
 410         },
 411         {
 412                 .ctl_name       = CTL_UNNUMBERED,
 413                 .procname       = "nsm_use_hostnames",
 414                 .data           = &nsm_use_hostnames,
 415                 .maxlen         = sizeof(int),
 416                 .mode           = 0644,
 417                 .proc_handler   = &proc_dointvec,
 418         },
 419         {
 420                 .ctl_name       = CTL_UNNUMBERED,
 421                 .procname       = "nsm_local_state",
 422                 .data           = &nsm_local_state,
 423                 .maxlen         = sizeof(int),
 424                 .mode           = 0644,
 425                 .proc_handler   = &proc_dointvec,
 426         },
 427         { .ctl_name = 0 }
 428 };
 429
 430 static ctl_table nlm_sysctl_dir[] = {
 431         {
 432                 .ctl_name       = CTL_UNNUMBERED,
 433                 .procname       = "nfs",
 434                 .mode           = 0555,
 435                 .child          = nlm_sysctls,
 436         },
 437         { .ctl_name = 0 }
 438 };
 439
 440 static ctl_table nlm_sysctl_root[] = {
 441         {
 442                 .ctl_name       = CTL_FS,
 443                 .procname       = "fs",
 444                 .mode           = 0555,
 445                 .child          = nlm_sysctl_dir,
 446         },
 447         { .ctl_name = 0 }
 448 };
 449
 450 /*
 451  * Module (and sysfs) parameters.
 452  */
 453
 454 #define param_set_min_max(name, type, which_strtol, min, max)           \
 455 static int param_set_##name(const char *val, struct kernel_param *kp)   \
 456 {                                                                       \
 457         char *endp;                                                     \
 458         __typeof__(type) num = which_strtol(val, &endp, 0);             \
 459         if (endp == val || *endp || num < (min) || num > (max))         \
 460                 return -EINVAL;                                         \
 461         *((int *) kp->arg) = num;                                       \
 462         return 0;                                                       \
 463 }
 464
 465 static inline int is_callback(u32 proc)
 466 {
 467         return proc == NLMPROC_GRANTED
 468                 || proc == NLMPROC_GRANTED_MSG
 469                 || proc == NLMPROC_TEST_RES
 470                 || proc == NLMPROC_LOCK_RES
 471                 || proc == NLMPROC_CANCEL_RES
 472                 || proc == NLMPROC_UNLOCK_RES
 473                 || proc == NLMPROC_NSM_NOTIFY;
 474 }
 475
 476
 477 static int lockd_authenticate(struct svc_rqst *rqstp)
 478 {
 479         rqstp->rq_client = NULL;
 480         switch (rqstp->rq_authop->flavour) {
 481                 case RPC_AUTH_NULL:
 482                 case RPC_AUTH_UNIX:
 483                         if (rqstp->rq_proc == 0)
 484                                 return SVC_OK;
 485                         if (is_callback(rqstp->rq_proc)) {
 486                                 /* Leave it to individual procedures to
 487                                  * call nlmsvc_lookup_host(rqstp)
 488                                  */
 489                                 return SVC_OK;
 490                         }
 491                         return svc_set_client(rqstp);
 492         }
 493         return SVC_DENIED;
 494 }
 495
 496
 497 param_set_min_max(port, int, simple_strtol, 0, 65535)
 498 param_set_min_max(grace_period, unsigned long, simple_strtoul,
 499                   nlm_grace_period_min, nlm_grace_period_max)
 500 param_set_min_max(timeout, unsigned long, simple_strtoul,
 501                   nlm_timeout_min, nlm_timeout_max)
 502
 503 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
 504 MODULE_DESCRIPTION("NFS file locking service version " LOCKD_VERSION ".");
 505 MODULE_LICENSE("GPL");
 506
 507 module_param_call(nlm_grace_period, param_set_grace_period, param_get_ulong,
 508                   &nlm_grace_period, 0644);
 509 module_param_call(nlm_timeout, param_set_timeout, param_get_ulong,
 510                   &nlm_timeout, 0644);
 511 module_param_call(nlm_udpport, param_set_port, param_get_int,
 512                   &nlm_udpport, 0644);
 513 module_param_call(nlm_tcpport, param_set_port, param_get_int,
 514                   &nlm_tcpport, 0644);
 515 module_param(nsm_use_hostnames, bool, 0644);
 516
 517 /*
 518  * Initialising and terminating the module.
 519  */
 520
 521 static int __init init_nlm(void)
 522 {
 523         nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
 524         return nlm_sysctl_table ? 0 : -ENOMEM;
 525 }
 526
 527 static void __exit exit_nlm(void)
 528 {
 529         /* FIXME: delete all NLM clients */
 530         nlm_shutdown_hosts();
 531         unregister_sysctl_table(nlm_sysctl_table);
 532 }
 533
 534 module_init(init_nlm);
 535 module_exit(exit_nlm);
 536
 537 /*
 538  * Define NLM program and procedures
 539  */
 540 static struct svc_version       nlmsvc_version1 = {
 541                 .vs_vers        = 1,
 542                 .vs_nproc       = 17,
 543                 .vs_proc        = nlmsvc_procedures,
 544                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 545 };
 546 static struct svc_version       nlmsvc_version3 = {
 547                 .vs_vers        = 3,
 548                 .vs_nproc       = 24,
 549                 .vs_proc        = nlmsvc_procedures,
 550                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 551 };
 552 #ifdef CONFIG_LOCKD_V4
 553 static struct svc_version       nlmsvc_version4 = {
 554                 .vs_vers        = 4,
 555                 .vs_nproc       = 24,
 556                 .vs_proc        = nlmsvc_procedures4,
 557                 .vs_xdrsize     = NLMSVC_XDRSIZE,
 558 };
 559 #endif
 560 static struct svc_version *     nlmsvc_version[] = {
 561         [1] = &nlmsvc_version1,
 562         [3] = &nlmsvc_version3,
 563 #ifdef CONFIG_LOCKD_V4
 564         [4] = &nlmsvc_version4,
 565 #endif
 566 };
 567
 568 static struct svc_stat          nlmsvc_stats;
 569
 570 #define NLM_NRVERS      ARRAY_SIZE(nlmsvc_version)
 571 static struct svc_program       nlmsvc_program = {
 572         .pg_prog                = NLM_PROGRAM,          /* program number */
 573         .pg_nvers               = NLM_NRVERS,           /* number of entries in nlmsvc_version */
 574         .pg_vers                = nlmsvc_version,       /* version table */
 575         .pg_name                = "lockd",              /* service name */
 576         .pg_class               = "nfsd",               /* share authentication with nfsd */
 577         .pg_stats               = &nlmsvc_stats,        /* stats table */
 578         .pg_authenticate = &lockd_authenticate  /* export authentication */
 579 };