libmultipath/uevent.c

   1 /*
   2  * uevent.c - trigger upon netlink uevents from the kernel
   3  *
   4  *      Only kernels from version 2.6.10* on provide the uevent netlink socket.
   5  *      Until the libc-kernel-headers are updated, you need to compile with:
   6  *
   7  *        gcc -I /lib/modules/`uname -r`/build/include -o uevent_listen uevent_listen.c
   8  *
   9  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
  10  *
  11  *      This program is free software; you can redistribute it and/or modify it
  12  *      under the terms of the GNU General Public License as published by the
  13  *      Free Software Foundation version 2 of the License.
  14  *
  15  *      This program is distributed in the hope that it will be useful, but
  16  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  *      General Public License for more details.
  19  *
  20  *      You should have received a copy of the GNU General Public License along
  21  *      with this program.  If not, see <http://www.gnu.org/licenses/>.
  22  *
  23  */
  24
  25 #include <unistd.h>
  26 #include <stdio.h>
  27 #include <stdbool.h>
  28 #include <errno.h>
  29 #include <stdlib.h>
  30 #include <stddef.h>
  31 #include <string.h>
  32 #include <fcntl.h>
  33 #include <time.h>
  34 #include <sys/socket.h>
  35 #include <sys/user.h>
  36 #include <sys/un.h>
  37 #include <poll.h>
  38 #include <linux/types.h>
  39 #include <linux/netlink.h>
  40 #include <pthread.h>
  41 #include <sys/mman.h>
  42 #include <sys/time.h>
  43 #include <libudev.h>
  44 #include <errno.h>
  45
  46 #include "memory.h"
  47 #include "debug.h"
  48 #include "list.h"
  49 #include "uevent.h"
  50 #include "vector.h"
  51 #include "structs.h"
  52 #include "util.h"
  53 #include "config.h"
  54 #include "blacklist.h"
  55
  56 #define MAX_ACCUMULATION_COUNT 2048
  57 #define MAX_ACCUMULATION_TIME 30*1000
  58 #define MIN_BURST_SPEED 10
  59
  60 typedef int (uev_trigger)(struct uevent *, void * trigger_data);
  61
  62 LIST_HEAD(uevq);
  63 pthread_mutex_t uevq_lock = PTHREAD_MUTEX_INITIALIZER;
  64 pthread_mutex_t *uevq_lockp = &uevq_lock;
  65 pthread_cond_t uev_cond = PTHREAD_COND_INITIALIZER;
  66 pthread_cond_t *uev_condp = &uev_cond;
  67 uev_trigger *my_uev_trigger;
  68 void * my_trigger_data;
  69 int servicing_uev;
  70
  71 int is_uevent_busy(void)
  72 {
  73         int empty;
  74
  75         pthread_mutex_lock(uevq_lockp);
  76         empty = list_empty(&uevq);
  77         pthread_mutex_unlock(uevq_lockp);
  78         return (!empty || servicing_uev);
  79 }
  80
  81 struct uevent * alloc_uevent (void)
  82 {
  83         struct uevent *uev = MALLOC(sizeof(struct uevent));
  84
  85         if (uev) {
  86                 INIT_LIST_HEAD(&uev->node);
  87                 INIT_LIST_HEAD(&uev->merge_node);
  88         }
  89
  90         return uev;
  91 }
  92
  93 void
  94 uevq_cleanup(struct list_head *tmpq)
  95 {
  96         struct uevent *uev, *tmp;
  97
  98         list_for_each_entry_safe(uev, tmp, tmpq, node) {
  99                 list_del_init(&uev->node);
 100
 101                 if (uev->udev)
 102                         udev_device_unref(uev->udev);
 103                 FREE(uev);
 104         }
 105 }
 106
 107 void
 108 uevent_get_wwid(struct uevent *uev)
 109 {
 110         int i;
 111         char *uid_attribute;
 112         struct config * conf;
 113
 114         conf = get_multipath_config();
 115         uid_attribute = parse_uid_attribute_by_attrs(conf->uid_attrs, uev->kernel);
 116         put_multipath_config(conf);
 117
 118         if (!uid_attribute)
 119                 return;
 120
 121         for (i = 0; uev->envp[i] != NULL; i++) {
 122                 if (!strncmp(uev->envp[i], uid_attribute, strlen(uid_attribute)) &&
 123                     strlen(uev->envp[i]) > strlen(uid_attribute) &&
 124                     uev->envp[i][strlen(uid_attribute)] == '=') {
 125                         uev->wwid = uev->envp[i] + strlen(uid_attribute) + 1;
 126                         break;
 127                 }
 128         }
 129         free(uid_attribute);
 130 }
 131
 132 bool
 133 uevent_need_merge(void)
 134 {
 135         struct config * conf;
 136         bool need_merge = false;
 137
 138         conf = get_multipath_config();
 139         if (conf->uid_attrs)
 140                 need_merge = true;
 141         put_multipath_config(conf);
 142
 143         return need_merge;
 144 }
 145
 146 static bool
 147 uevent_can_discard_by_devpath(const char *devpath)
 148 {
 149         static const char BLOCK[] = "/block/";
 150         const char *tmp = strstr(devpath, BLOCK);
 151
 152         if (tmp == NULL) {
 153                 condlog(4, "no /block/ in '%s'", devpath);
 154                 return true;
 155         }
 156         tmp += sizeof(BLOCK) - 1;
 157         if (*tmp == '\0')
 158                 /* just ".../block/" - discard */
 159                 return true;
 160         /*
 161          * If there are more path elements after ".../block/xyz",
 162          * it's a partition - discard it; but don't discard ".../block/sda/".
 163          */
 164         tmp = strchr(tmp, '/');
 165         return tmp != NULL && *(tmp + 1) != '\0';
 166 }
 167
 168 bool
 169 uevent_can_discard(struct uevent *uev)
 170 {
 171         struct config * conf;
 172
 173         if (uevent_can_discard_by_devpath(uev->devpath))
 174                 return true;
 175
 176         /*
 177          * do not filter dm devices by devnode
 178          */
 179         if (!strncmp(uev->kernel, "dm-", 3))
 180                 return false;
 181         /*
 182          * filter paths devices by devnode
 183          */
 184         conf = get_multipath_config();
 185         if (filter_devnode(conf->blist_devnode, conf->elist_devnode,
 186                            uev->kernel) > 0) {
 187                 put_multipath_config(conf);
 188                 return true;
 189         }
 190         put_multipath_config(conf);
 191
 192         return false;
 193 }
 194
 195 bool
 196 uevent_can_filter(struct uevent *earlier, struct uevent *later)
 197 {
 198
 199         /*
 200          * filter earlier uvents if path has removed later. Eg:
 201          * "add path1 |chang path1 |add path2 |remove path1"
 202          * can filter as:
 203          * "add path2 |remove path1"
 204          * uevents "add path1" and "chang path1" are filtered out
 205          */
 206         if (!strcmp(earlier->kernel, later->kernel) &&
 207                 !strcmp(later->action, "remove") &&
 208                 strncmp(later->kernel, "dm-", 3)) {
 209                 return true;
 210         }
 211
 212         /*
 213          * filter change uvents if add uevents exist. Eg:
 214          * "change path1| add path1 |add path2"
 215          * can filter as:
 216          * "add path1 |add path2"
 217          * uevent "chang path1" is filtered out
 218          */
 219         if (!strcmp(earlier->kernel, later->kernel) &&
 220                 !strcmp(earlier->action, "change") &&
 221                 !strcmp(later->action, "add") &&
 222                 strncmp(later->kernel, "dm-", 3)) {
 223                 return true;
 224         }
 225
 226         return false;
 227 }
 228
 229 bool
 230 merge_need_stop(struct uevent *earlier, struct uevent *later)
 231 {
 232         /*
 233          * dm uevent do not try to merge with left uevents
 234          */
 235         if (!strncmp(later->kernel, "dm-", 3))
 236                 return true;
 237
 238         /*
 239          * we can not make a jugement without wwid,
 240          * so it is sensible to stop merging
 241          */
 242         if (!earlier->wwid || !later->wwid)
 243                 return true;
 244         /*
 245          * uevents merging stoped
 246          * when we meet an opposite action uevent from the same LUN to AVOID
 247          * "add path1 |remove path1 |add path2 |remove path2 |add path3"
 248          * to merge as "remove path1, path2" and "add path1, path2, path3"
 249          * OR
 250          * "remove path1 |add path1 |remove path2 |add path2 |remove path3"
 251          * to merge as "add path1, path2" and "remove path1, path2, path3"
 252          * SO
 253          * when we meet a non-change uevent from the same LUN
 254          * with the same wwid and different action
 255          * it would be better to stop merging.
 256          */
 257         if (!strcmp(earlier->wwid, later->wwid) &&
 258             strcmp(earlier->action, later->action) &&
 259             strcmp(earlier->action, "change") &&
 260             strcmp(later->action, "change"))
 261                 return true;
 262
 263         return false;
 264 }
 265
 266 bool
 267 uevent_can_merge(struct uevent *earlier, struct uevent *later)
 268 {
 269         /* merge paths uevents
 270          * whose wwids exsit and are same
 271          * and actions are same,
 272          * and actions are addition or deletion
 273          */
 274         if (earlier->wwid && later->wwid &&
 275             !strcmp(earlier->wwid, later->wwid) &&
 276             !strcmp(earlier->action, later->action) &&
 277             strncmp(earlier->action, "change", 6) &&
 278             strncmp(earlier->kernel, "dm-", 3)) {
 279                 return true;
 280         }
 281
 282         return false;
 283 }
 284
 285 void
 286 uevent_prepare(struct list_head *tmpq)
 287 {
 288         struct uevent *uev, *tmp;
 289
 290         list_for_each_entry_reverse_safe(uev, tmp, tmpq, node) {
 291                 if (uevent_can_discard(uev)) {
 292                         list_del_init(&uev->node);
 293                         if (uev->udev)
 294                                 udev_device_unref(uev->udev);
 295                         FREE(uev);
 296                         continue;
 297                 }
 298
 299                 if (strncmp(uev->kernel, "dm-", 3) &&
 300                     uevent_need_merge())
 301                         uevent_get_wwid(uev);
 302         }
 303 }
 304
 305 void
 306 uevent_filter(struct uevent *later, struct list_head *tmpq)
 307 {
 308         struct uevent *earlier, *tmp;
 309
 310         list_for_some_entry_reverse_safe(earlier, tmp, &later->node, tmpq, node) {
 311                 /*
 312                  * filter unnessary earlier uevents
 313                  * by the later uevent
 314                  */
 315                 if (uevent_can_filter(earlier, later)) {
 316                         condlog(2, "uevent: %s-%s has filtered by uevent: %s-%s",
 317                                 earlier->kernel, earlier->action,
 318                                 later->kernel, later->action);
 319
 320                         list_del_init(&earlier->node);
 321                         if (earlier->udev)
 322                                 udev_device_unref(earlier->udev);
 323                         FREE(earlier);
 324                 }
 325         }
 326 }
 327
 328 void
 329 uevent_merge(struct uevent *later, struct list_head *tmpq)
 330 {
 331         struct uevent *earlier, *tmp;
 332
 333         list_for_some_entry_reverse_safe(earlier, tmp, &later->node, tmpq, node) {
 334                 if (merge_need_stop(earlier, later))
 335                         break;
 336                 /*
 337                  * merge earlier uevents to the later uevent
 338                  */
 339                 if (uevent_can_merge(earlier, later)) {
 340                         condlog(2, "merged uevent: %s-%s-%s with uevent: %s-%s-%s",
 341                                 earlier->action, earlier->kernel, earlier->wwid,
 342                                 later->action, later->kernel, later->wwid);
 343
 344                         list_move(&earlier->node, &later->merge_node);
 345                 }
 346         }
 347 }
 348
 349 void
 350 merge_uevq(struct list_head *tmpq)
 351 {
 352         struct uevent *later;
 353
 354         uevent_prepare(tmpq);
 355         list_for_each_entry_reverse(later, tmpq, node) {
 356                 uevent_filter(later, tmpq);
 357                 if(uevent_need_merge())
 358                         uevent_merge(later, tmpq);
 359         }
 360 }
 361
 362 void
 363 service_uevq(struct list_head *tmpq)
 364 {
 365         struct uevent *uev, *tmp;
 366
 367         list_for_each_entry_safe(uev, tmp, tmpq, node) {
 368                 list_del_init(&uev->node);
 369
 370                 if (my_uev_trigger && my_uev_trigger(uev, my_trigger_data))
 371                         condlog(0, "uevent trigger error");
 372
 373                 uevq_cleanup(&uev->merge_node);
 374
 375                 if (uev->udev)
 376                         udev_device_unref(uev->udev);
 377                 FREE(uev);
 378         }
 379 }
 380
 381 static void uevent_cleanup(void *arg)
 382 {
 383         struct udev *udev = arg;
 384
 385         condlog(3, "Releasing uevent_listen() resources");
 386         udev_unref(udev);
 387 }
 388
 389 /*
 390  * Service the uevent queue.
 391  */
 392 int uevent_dispatch(int (*uev_trigger)(struct uevent *, void * trigger_data),
 393                     void * trigger_data)
 394 {
 395         my_uev_trigger = uev_trigger;
 396         my_trigger_data = trigger_data;
 397
 398         mlockall(MCL_CURRENT | MCL_FUTURE);
 399
 400         while (1) {
 401                 LIST_HEAD(uevq_tmp);
 402
 403                 pthread_mutex_lock(uevq_lockp);
 404                 servicing_uev = 0;
 405                 /*
 406                  * Condition signals are unreliable,
 407                  * so make sure we only wait if we have to.
 408                  */
 409                 if (list_empty(&uevq)) {
 410                         pthread_cond_wait(uev_condp, uevq_lockp);
 411                 }
 412                 servicing_uev = 1;
 413                 list_splice_init(&uevq, &uevq_tmp);
 414                 pthread_mutex_unlock(uevq_lockp);
 415                 if (!my_uev_trigger)
 416                         break;
 417                 merge_uevq(&uevq_tmp);
 418                 service_uevq(&uevq_tmp);
 419         }
 420         condlog(3, "Terminating uev service queue");
 421         uevq_cleanup(&uevq);
 422         return 0;
 423 }
 424
 425 struct uevent *uevent_from_buffer(char *buf, ssize_t buflen)
 426 {
 427         struct uevent *uev;
 428         char *buffer;
 429         size_t bufpos;
 430         int i;
 431         char *pos;
 432
 433         uev = alloc_uevent();
 434         if (!uev) {
 435                 condlog(1, "lost uevent, oom");
 436                 return NULL;
 437         }
 438
 439         if ((size_t)buflen > sizeof(buf)-1)
 440                 buflen = sizeof(buf)-1;
 441
 442         /*
 443          * Copy the shared receive buffer contents to buffer private
 444          * to this uevent so we can immediately reuse the shared buffer.
 445          */
 446         memcpy(uev->buffer, buf, HOTPLUG_BUFFER_SIZE + OBJECT_SIZE);
 447         buffer = uev->buffer;
 448         buffer[buflen] = '\0';
 449
 450         /* save start of payload */
 451         bufpos = strlen(buffer) + 1;
 452
 453         /* action string */
 454         uev->action = buffer;
 455         pos = strchr(buffer, '@');
 456         if (!pos) {
 457                 condlog(3, "bad action string '%s'", buffer);
 458                 FREE(uev);
 459                 return NULL;
 460         }
 461         pos[0] = '\0';
 462
 463         /* sysfs path */
 464         uev->devpath = &pos[1];
 465
 466         /* hotplug events have the environment attached - reconstruct envp[] */
 467         for (i = 0; (bufpos < (size_t)buflen) && (i < HOTPLUG_NUM_ENVP-1); i++) {
 468                 int keylen;
 469                 char *key;
 470
 471                 key = &buffer[bufpos];
 472                 keylen = strlen(key);
 473                 uev->envp[i] = key;
 474                 /* Filter out sequence number */
 475                 if (strncmp(key, "SEQNUM=", 7) == 0) {
 476                         char *eptr;
 477
 478                         uev->seqnum = strtoul(key + 7, &eptr, 10);
 479                         if (eptr == key + 7)
 480                                 uev->seqnum = -1;
 481                 }
 482                 bufpos += keylen + 1;
 483         }
 484         uev->envp[i] = NULL;
 485
 486         condlog(3, "uevent %ld '%s' from '%s'", uev->seqnum,
 487                 uev->action, uev->devpath);
 488         uev->kernel = strrchr(uev->devpath, '/');
 489         if (uev->kernel)
 490                 uev->kernel++;
 491
 492         /* print payload environment */
 493         for (i = 0; uev->envp[i] != NULL; i++)
 494                 condlog(5, "%s", uev->envp[i]);
 495
 496         return uev;
 497 }
 498
 499 int failback_listen(void)
 500 {
 501         int sock;
 502         struct sockaddr_nl snl;
 503         struct sockaddr_un sun;
 504         socklen_t addrlen;
 505         int retval;
 506         int rcvbufsz = 128*1024;
 507         int rcvsz = 0;
 508         int rcvszsz = sizeof(rcvsz);
 509         unsigned int *prcvszsz = (unsigned int *)&rcvszsz;
 510         const int feature_on = 1;
 511         /*
 512          * First check whether we have a udev socket
 513          */
 514         memset(&sun, 0x00, sizeof(struct sockaddr_un));
 515         sun.sun_family = AF_LOCAL;
 516         strcpy(&sun.sun_path[1], "/org/kernel/dm/multipath_event");
 517         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(sun.sun_path+1) + 1;
 518
 519         sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 520         if (sock >= 0) {
 521
 522                 condlog(3, "reading events from udev socket.");
 523
 524                 /* the bind takes care of ensuring only one copy running */
 525                 retval = bind(sock, (struct sockaddr *) &sun, addrlen);
 526                 if (retval < 0) {
 527                         condlog(0, "bind failed, exit");
 528                         goto exit;
 529                 }
 530
 531                 /* enable receiving of the sender credentials */
 532                 retval = setsockopt(sock, SOL_SOCKET, SO_PASSCRED,
 533                                     &feature_on, sizeof(feature_on));
 534                 if (retval < 0) {
 535                         condlog(0, "failed to enable credential passing, exit");
 536                         goto exit;
 537                 }
 538
 539         } else {
 540                 /* Fallback to read kernel netlink events */
 541                 memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 542                 snl.nl_family = AF_NETLINK;
 543                 snl.nl_pid = getpid();
 544                 snl.nl_groups = 0x01;
 545
 546                 sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 547                 if (sock == -1) {
 548                         condlog(0, "error getting socket, exit");
 549                         return 1;
 550                 }
 551
 552                 condlog(3, "reading events from kernel.");
 553
 554                 /*
 555                  * try to avoid dropping uevents, even so, this is not a guarantee,
 556                  * but it does help to change the netlink uevent socket's
 557                  * receive buffer threshold from the default value of 106,496 to
 558                  * the maximum value of 262,142.
 559                  */
 560                 retval = setsockopt(sock, SOL_SOCKET, SO_RCVBUF, &rcvbufsz,
 561                                     sizeof(rcvbufsz));
 562
 563                 if (retval < 0) {
 564                         condlog(0, "error setting receive buffer size for socket, exit");
 565                         exit(1);
 566                 }
 567                 retval = getsockopt(sock, SOL_SOCKET, SO_RCVBUF, &rcvsz, prcvszsz);
 568                 if (retval < 0) {
 569                         condlog(0, "error setting receive buffer size for socket, exit");
 570                         exit(1);
 571                 }
 572                 condlog(3, "receive buffer size for socket is %u.", rcvsz);
 573
 574                 /* enable receiving of the sender credentials */
 575                 if (setsockopt(sock, SOL_SOCKET, SO_PASSCRED,
 576                                &feature_on, sizeof(feature_on)) < 0) {
 577                         condlog(0, "error on enabling credential passing for socket");
 578                         exit(1);
 579                 }
 580
 581                 retval = bind(sock, (struct sockaddr *) &snl,
 582                               sizeof(struct sockaddr_nl));
 583                 if (retval < 0) {
 584                         condlog(0, "bind failed, exit");
 585                         goto exit;
 586                 }
 587         }
 588
 589         while (1) {
 590                 size_t bufpos;
 591                 ssize_t buflen;
 592                 struct uevent *uev;
 593                 struct msghdr smsg;
 594                 struct iovec iov;
 595                 char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 596                 struct cmsghdr *cmsg;
 597                 struct ucred *cred;
 598                 static char buf[HOTPLUG_BUFFER_SIZE + OBJECT_SIZE];
 599
 600                 memset(buf, 0x00, sizeof(buf));
 601                 iov.iov_base = &buf;
 602                 iov.iov_len = sizeof(buf);
 603                 memset (&smsg, 0x00, sizeof(struct msghdr));
 604                 smsg.msg_iov = &iov;
 605                 smsg.msg_iovlen = 1;
 606                 smsg.msg_control = cred_msg;
 607                 smsg.msg_controllen = sizeof(cred_msg);
 608
 609                 buflen = recvmsg(sock, &smsg, 0);
 610                 if (buflen < 0) {
 611                         if (errno != EINTR)
 612                                 condlog(0, "error receiving message, errno %d", errno);
 613                         continue;
 614                 }
 615
 616                 cmsg = CMSG_FIRSTHDR(&smsg);
 617                 if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 618                         condlog(3, "no sender credentials received, message ignored");
 619                         continue;
 620                 }
 621
 622                 cred = (struct ucred *)CMSG_DATA(cmsg);
 623                 if (cred->uid != 0) {
 624                         condlog(3, "sender uid=%d, message ignored", cred->uid);
 625                         continue;
 626                 }
 627
 628                 /* skip header */
 629                 bufpos = strlen(buf) + 1;
 630                 if (bufpos < sizeof("a@/d") || bufpos >= sizeof(buf)) {
 631                         condlog(3, "invalid message length");
 632                         continue;
 633                 }
 634
 635                 /* check message header */
 636                 if (strstr(buf, "@/") == NULL) {
 637                         condlog(3, "unrecognized message header");
 638                         continue;
 639                 }
 640                 if ((size_t)buflen > sizeof(buf)-1) {
 641                         condlog(2, "buffer overflow for received uevent");
 642                         buflen = sizeof(buf)-1;
 643                 }
 644
 645                 uev = uevent_from_buffer(buf, buflen);
 646                 if (!uev)
 647                         continue;
 648                 /*
 649                  * Queue uevent and poke service pthread.
 650                  */
 651                 pthread_mutex_lock(uevq_lockp);
 652                 list_add_tail(&uev->node, &uevq);
 653                 pthread_cond_signal(uev_condp);
 654                 pthread_mutex_unlock(uevq_lockp);
 655         }
 656
 657 exit:
 658         close(sock);
 659         return 1;
 660 }
 661
 662 struct uevent *uevent_from_udev_device(struct udev_device *dev)
 663 {
 664         struct uevent *uev;
 665         int i = 0;
 666         char *pos, *end;
 667         struct udev_list_entry *list_entry;
 668
 669         uev = alloc_uevent();
 670         if (!uev) {
 671                 udev_device_unref(dev);
 672                 condlog(1, "lost uevent, oom");
 673                 return NULL;
 674         }
 675         pos = uev->buffer;
 676         end = pos + HOTPLUG_BUFFER_SIZE + OBJECT_SIZE - 1;
 677         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(dev)) {
 678                 const char *name, *value;
 679                 int bytes;
 680
 681                 name = udev_list_entry_get_name(list_entry);
 682                 if (!name)
 683                         name = "(null)";
 684                 value = udev_list_entry_get_value(list_entry);
 685                 if (!value)
 686                         value = "(null)";
 687                 bytes = snprintf(pos, end - pos, "%s=%s", name, value);
 688                 if (pos + bytes >= end) {
 689                         condlog(2, "buffer overflow for uevent");
 690                         break;
 691                 }
 692                 uev->envp[i] = pos;
 693                 pos += bytes;
 694                 *pos = '\0';
 695                 pos++;
 696                 if (strcmp(name, "DEVPATH") == 0)
 697                         uev->devpath = uev->envp[i] + 8;
 698                 if (strcmp(name, "ACTION") == 0)
 699                         uev->action = uev->envp[i] + 7;
 700                 i++;
 701                 if (i == HOTPLUG_NUM_ENVP - 1)
 702                         break;
 703         }
 704         uev->udev = dev;
 705         uev->envp[i] = NULL;
 706
 707         condlog(3, "uevent '%s' from '%s'", uev->action, uev->devpath);
 708         uev->kernel = strrchr(uev->devpath, '/');
 709         if (uev->kernel)
 710                 uev->kernel++;
 711
 712         /* print payload environment */
 713         for (i = 0; uev->envp[i] != NULL; i++)
 714                 condlog(5, "%s", uev->envp[i]);
 715         return uev;
 716 }
 717
 718 bool uevent_burst(struct timeval *start_time, int events)
 719 {
 720         struct timeval diff_time, end_time;
 721         unsigned long speed;
 722         unsigned long eclipse_ms;
 723
 724         if(events > MAX_ACCUMULATION_COUNT) {
 725                 condlog(2, "burst got %u uevents, too much uevents, stopped", events);
 726                 return false;
 727         }
 728
 729         gettimeofday(&end_time, NULL);
 730         timersub(&end_time, start_time, &diff_time);
 731
 732         eclipse_ms = diff_time.tv_sec * 1000 + diff_time.tv_usec / 1000;
 733
 734         if (eclipse_ms == 0)
 735                 return true;
 736
 737         if (eclipse_ms > MAX_ACCUMULATION_TIME) {
 738                 condlog(2, "burst continued %lu ms, too long time, stopped", eclipse_ms);
 739                 return false;
 740         }
 741
 742         speed = (events * 1000) / eclipse_ms;
 743         if (speed > MIN_BURST_SPEED)
 744                 return true;
 745
 746         return false;
 747 }
 748
 749 int uevent_listen(struct udev *udev)
 750 {
 751         int err = 2;
 752         struct udev_monitor *monitor = NULL;
 753         int fd, socket_flags, events;
 754         struct timeval start_time;
 755         int need_failback = 1;
 756         int timeout = 30;
 757         LIST_HEAD(uevlisten_tmp);
 758
 759         /*
 760          * Queue uevents for service by dedicated thread so that the uevent
 761          * listening thread does not block on multipathd locks (vecs->lock)
 762          * thereby not getting to empty the socket's receive buffer queue
 763          * often enough.
 764          */
 765         if (!udev) {
 766                 condlog(1, "no udev context");
 767                 return 1;
 768         }
 769         udev_ref(udev);
 770         pthread_cleanup_push(uevent_cleanup, udev);
 771
 772         monitor = udev_monitor_new_from_netlink(udev, "udev");
 773         if (!monitor) {
 774                 condlog(2, "failed to create udev monitor");
 775                 goto out;
 776         }
 777 #ifdef LIBUDEV_API_RECVBUF
 778         if (udev_monitor_set_receive_buffer_size(monitor, 128 * 1024 * 1024))
 779                 condlog(2, "failed to increase buffer size");
 780 #endif
 781         fd = udev_monitor_get_fd(monitor);
 782         if (fd < 0) {
 783                 condlog(2, "failed to get monitor fd");
 784                 goto out;
 785         }
 786         socket_flags = fcntl(fd, F_GETFL);
 787         if (socket_flags < 0) {
 788                 condlog(2, "failed to get monitor socket flags : %s",
 789                         strerror(errno));
 790                 goto out;
 791         }
 792         if (fcntl(fd, F_SETFL, socket_flags & ~O_NONBLOCK) < 0) {
 793                 condlog(2, "failed to set monitor socket flags : %s",
 794                         strerror(errno));
 795                 goto out;
 796         }
 797         err = udev_monitor_filter_add_match_subsystem_devtype(monitor, "block",
 798                                                               NULL);
 799         if (err)
 800                 condlog(2, "failed to create filter : %s", strerror(-err));
 801         err = udev_monitor_enable_receiving(monitor);
 802         if (err) {
 803                 condlog(2, "failed to enable receiving : %s", strerror(-err));
 804                 goto out;
 805         }
 806
 807         events = 0;
 808         gettimeofday(&start_time, NULL);
 809         while (1) {
 810                 struct uevent *uev;
 811                 struct udev_device *dev;
 812                 struct pollfd ev_poll;
 813                 int poll_timeout;
 814                 int fdcount;
 815
 816                 memset(&ev_poll, 0, sizeof(struct pollfd));
 817                 ev_poll.fd = fd;
 818                 ev_poll.events = POLLIN;
 819                 poll_timeout = timeout * 1000;
 820                 errno = 0;
 821                 fdcount = poll(&ev_poll, 1, poll_timeout);
 822                 if (fdcount && ev_poll.revents & POLLIN) {
 823                         timeout = uevent_burst(&start_time, events + 1) ? 1 : 0;
 824                         dev = udev_monitor_receive_device(monitor);
 825                         if (!dev) {
 826                                 condlog(0, "failed getting udev device");
 827                                 continue;
 828                         }
 829                         uev = uevent_from_udev_device(dev);
 830                         if (!uev)
 831                                 continue;
 832                         list_add_tail(&uev->node, &uevlisten_tmp);
 833                         events++;
 834                         continue;
 835                 }
 836                 if (fdcount < 0) {
 837                         if (errno == EINTR)
 838                                 continue;
 839
 840                         condlog(0, "error receiving "
 841                                 "uevent message: %m");
 842                         err = -errno;
 843                         break;
 844                 }
 845                 if (!list_empty(&uevlisten_tmp)) {
 846                         /*
 847                          * Queue uevents and poke service pthread.
 848                          */
 849                         condlog(3, "Forwarding %d uevents", events);
 850                         pthread_mutex_lock(uevq_lockp);
 851                         list_splice_tail_init(&uevlisten_tmp, &uevq);
 852                         pthread_cond_signal(uev_condp);
 853                         pthread_mutex_unlock(uevq_lockp);
 854                         events = 0;
 855                 }
 856                 gettimeofday(&start_time, NULL);
 857                 timeout = 30;
 858         }
 859         need_failback = 0;
 860 out:
 861         if (monitor)
 862                 udev_monitor_unref(monitor);
 863         if (need_failback)
 864                 err = failback_listen();
 865         pthread_cleanup_pop(1);
 866         return err;
 867 }
 868
 869 int uevent_get_major(struct uevent *uev)
 870 {
 871         char *p, *q;
 872         int i, major = -1;
 873
 874         for (i = 0; uev->envp[i] != NULL; i++) {
 875                 if (!strncmp(uev->envp[i], "MAJOR", 5) && strlen(uev->envp[i]) > 6) {
 876                         p = uev->envp[i] + 6;
 877                         major = strtoul(p, &q, 10);
 878                         if (p == q) {
 879                                 condlog(2, "invalid major '%s'", p);
 880                                 major = -1;
 881                         }
 882                         break;
 883                 }
 884         }
 885         return major;
 886 }
 887
 888 int uevent_get_minor(struct uevent *uev)
 889 {
 890         char *p, *q;
 891         int i, minor = -1;
 892
 893         for (i = 0; uev->envp[i] != NULL; i++) {
 894                 if (!strncmp(uev->envp[i], "MINOR", 5) && strlen(uev->envp[i]) > 6) {
 895                         p = uev->envp[i] + 6;
 896                         minor = strtoul(p, &q, 10);
 897                         if (p == q) {
 898                                 condlog(2, "invalid minor '%s'", p);
 899                                 minor = -1;
 900                         }
 901                         break;
 902                 }
 903         }
 904         return minor;
 905 }
 906
 907 int uevent_get_disk_ro(struct uevent *uev)
 908 {
 909         char *p, *q;
 910         int i, ro = -1;
 911
 912         for (i = 0; uev->envp[i] != NULL; i++) {
 913                 if (!strncmp(uev->envp[i], "DISK_RO", 6) && strlen(uev->envp[i]) > 7) {
 914                         p = uev->envp[i] + 8;
 915                         ro = strtoul(p, &q, 10);
 916                         if (p == q) {
 917                                 condlog(2, "invalid read_only setting '%s'", p);
 918                                 ro = -1;
 919                         }
 920                         break;
 921                 }
 922         }
 923         return ro;
 924 }
 925
 926 char *uevent_get_dm_name(struct uevent *uev)
 927 {
 928         char *p = NULL;
 929         int i;
 930
 931         for (i = 0; uev->envp[i] != NULL; i++) {
 932                 if (!strncmp(uev->envp[i], "DM_NAME", 6) &&
 933                     strlen(uev->envp[i]) > 7) {
 934                         p = MALLOC(strlen(uev->envp[i] + 8) + 1);
 935                         strcpy(p, uev->envp[i] + 8);
 936                         break;
 937                 }
 938         }
 939         return p;
 940 }