udevd.c

   1 /*
   2  * udevd.c - event listener and serializer
   3  *
   4  * Copyright (C) 2004-2005 Kay Sievers <kay.sievers@vrfy.org>
   5  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   6  *
   7  *
   8  *      This program is free software; you can redistribute it and/or modify it
   9  *      under the terms of the GNU General Public License as published by the
  10  *      Free Software Foundation version 2 of the License.
  11  *
  12  *      This program is distributed in the hope that it will be useful, but
  13  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *      General Public License for more details.
  16  *
  17  *      You should have received a copy of the GNU General Public License along
  18  *      with this program; if not, write to the Free Software Foundation, Inc.,
  19  *      675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  */
  22
  23 #include <stddef.h>
  24 #include <signal.h>
  25 #include <unistd.h>
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <ctype.h>
  31 #include <dirent.h>
  32 #include <fcntl.h>
  33 #include <syslog.h>
  34 #include <time.h>
  35 #include <sys/select.h>
  36 #include <sys/wait.h>
  37 #include <sys/types.h>
  38 #include <sys/socket.h>
  39 #include <sys/un.h>
  40 #include <sys/stat.h>
  41 #include <sys/ioctl.h>
  42 #include <linux/types.h>
  43 #include <linux/netlink.h>
  44
  45 #include "udev.h"
  46 #include "udev_rules.h"
  47 #include "udevd.h"
  48
  49 static struct udev_rules rules;
  50 static int udevd_sock;
  51 static int uevent_netlink_sock;
  52 static int inotify_fd;
  53 static pid_t sid;
  54
  55 static int signal_pipe[2] = {-1, -1};
  56 static volatile int sigchilds_waiting;
  57 static volatile int udev_exit;
  58 static volatile int reload_config;
  59 static int run_exec_q;
  60 static int stop_exec_q;
  61 static int max_childs;
  62 static int max_childs_running;
  63 static char udev_log[32];
  64
  65 static LIST_HEAD(exec_list);
  66 static LIST_HEAD(running_list);
  67
  68
  69 #ifdef USE_LOG
  70 void log_message(int priority, const char *format, ...)
  71 {
  72         va_list args;
  73
  74         if (priority > udev_log_priority)
  75                 return;
  76
  77         va_start(args, format);
  78         vsyslog(priority, format, args);
  79         va_end(args);
  80 }
  81 #endif
  82
  83 static void asmlinkage udev_event_sig_handler(int signum)
  84 {
  85         if (signum == SIGALRM)
  86                 exit(1);
  87 }
  88
  89 static int udev_event_process(struct uevent_msg *msg)
  90 {
  91         struct sigaction act;
  92         struct udevice *udev;
  93         int i;
  94         int retval;
  95
  96         /* set signal handlers */
  97         memset(&act, 0x00, sizeof(act));
  98         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
  99         sigemptyset (&act.sa_mask);
 100         act.sa_flags = 0;
 101         sigaction(SIGALRM, &act, NULL);
 102
 103         /* trigger timeout to prevent hanging processes */
 104         alarm(UDEV_ALARM_TIMEOUT);
 105
 106         /* reconstruct event environment from message */
 107         for (i = 0; msg->envp[i]; i++)
 108                 putenv(msg->envp[i]);
 109
 110         udev = udev_device_init();
 111         if (udev == NULL)
 112                 return -1;
 113         strlcpy(udev->action, msg->action, sizeof(udev->action));
 114         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem);
 115         udev->devt = msg->devt;
 116
 117         retval = udev_device_event(&rules, udev);
 118
 119         /* run programs collected by RUN-key*/
 120         if (retval == 0) {
 121                 struct name_entry *name_loop;
 122
 123                 list_for_each_entry(name_loop, &udev->run_list, node) {
 124                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 125                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], msg->devpath, msg->action);
 126                         else {
 127                                 char program[PATH_SIZE];
 128
 129                                 strlcpy(program, name_loop->name, sizeof(program));
 130                                 udev_rules_apply_format(udev, program, sizeof(program));
 131                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 132                                                 (udev_log_priority >= LOG_INFO)))
 133                                         retval = -1;
 134                         }
 135                 }
 136         }
 137
 138         udev_device_cleanup(udev);
 139         return retval;
 140 }
 141
 142 enum event_state {
 143         EVENT_QUEUED,
 144         EVENT_FINISHED,
 145         EVENT_FAILED,
 146 };
 147
 148 static void export_event_state(struct uevent_msg *msg, enum event_state state)
 149 {
 150         char filename[PATH_SIZE];
 151         char filename_failed[PATH_SIZE];
 152         char target[PATH_SIZE];
 153         size_t start, end, i;
 154         struct uevent_msg *loop_msg;
 155
 156         /* add location of queue files */
 157         strlcpy(filename, udev_root, sizeof(filename));
 158         strlcat(filename, "/", sizeof(filename));
 159         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 160         end = strlcat(filename, msg->devpath, sizeof(filename));
 161         if (end > sizeof(filename))
 162                 end = sizeof(filename);
 163
 164         /* replace '/' to transform path into a filename */
 165         for (i = start+1; i < end; i++)
 166                 if (filename[i] == '/')
 167                         filename[i] = PATH_TO_NAME_CHAR;
 168
 169         /* add location of failed files */
 170         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 171         strlcat(filename_failed, "/", sizeof(filename_failed));
 172         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 173         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 174         if (end > sizeof(filename_failed))
 175                 end = sizeof(filename_failed);
 176
 177         /* replace '/' to transform path into a filename */
 178         for (i = start+1; i < end; i++)
 179                 if (filename_failed[i] == '/')
 180                         filename_failed[i] = PATH_TO_NAME_CHAR;
 181
 182         switch (state) {
 183         case EVENT_QUEUED:
 184                 unlink(filename_failed);
 185                 delete_path(filename_failed);
 186
 187                 strlcpy(target, sysfs_path, sizeof(target));
 188                 strlcat(target, msg->devpath, sizeof(target));
 189                 create_path(filename);
 190                 symlink(target, filename);
 191                 return;
 192         case EVENT_FINISHED:
 193         case EVENT_FAILED:
 194                 unlink(filename_failed);
 195                 delete_path(filename_failed);
 196
 197                 /* don't remove, if events for the same path are still pending */
 198                 list_for_each_entry(loop_msg, &running_list, node)
 199                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 200                                 return;
 201
 202                 /* move failed events to the failed directory */
 203                 if (state == EVENT_FAILED) {
 204                         create_path(filename_failed);
 205                         rename(filename, filename_failed);
 206                 } else {
 207                         unlink(filename);
 208                 }
 209
 210                 /* clean up the queue directory */
 211                 delete_path(filename);
 212
 213                 return;
 214         }
 215 }
 216
 217 static void msg_queue_delete(struct uevent_msg *msg)
 218 {
 219         list_del(&msg->node);
 220
 221         /* mark as failed, if add event returns non-zero */
 222         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 223                 export_event_state(msg, EVENT_FAILED);
 224         else
 225                 export_event_state(msg, EVENT_FINISHED);
 226
 227         free(msg);
 228 }
 229
 230 static void udev_event_run(struct uevent_msg *msg)
 231 {
 232         pid_t pid;
 233         int retval;
 234
 235         pid = fork();
 236         switch (pid) {
 237         case 0:
 238                 /* child */
 239                 close(uevent_netlink_sock);
 240                 close(udevd_sock);
 241                 if (inotify_fd > 0)
 242                         close(inotify_fd);
 243                 close(signal_pipe[READ_END]);
 244                 close(signal_pipe[WRITE_END]);
 245                 logging_close();
 246
 247                 logging_init("udevd-event");
 248                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 249                 retval = udev_event_process(msg);
 250                 info("seq %llu finished", msg->seqnum);
 251
 252                 logging_close();
 253                 if (retval)
 254                         exit(1);
 255                 exit(0);
 256         case -1:
 257                 err("fork of child failed: %s", strerror(errno));
 258                 msg_queue_delete(msg);
 259                 break;
 260         default:
 261                 /* get SIGCHLD in main loop */
 262                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 263                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 264                 msg->pid = pid;
 265         }
 266 }
 267
 268 static void msg_queue_insert(struct uevent_msg *msg)
 269 {
 270         msg->queue_time = time(NULL);
 271
 272         export_event_state(msg, EVENT_QUEUED);
 273
 274         /* run all events with a timeout set immediately */
 275         if (msg->timeout != 0) {
 276                 list_add_tail(&msg->node, &running_list);
 277                 udev_event_run(msg);
 278                 return;
 279         }
 280
 281         list_add_tail(&msg->node, &exec_list);
 282         run_exec_q = 1;
 283 }
 284
 285 /* runs event and removes event from run queue when finished */
 286 static int running_processes(void)
 287 {
 288         int f;
 289         static char buf[4096];
 290         int len;
 291         int running;
 292         const char *pos;
 293
 294         f = open("/proc/stat", O_RDONLY);
 295         if (f == -1)
 296                 return -1;
 297
 298         len = read(f, buf, sizeof(buf)-1);
 299         close(f);
 300
 301         if (len <= 0)
 302                 return -1;
 303         else
 304                 buf[len] = '\0';
 305
 306         pos = strstr(buf, "procs_running ");
 307         if (pos == NULL)
 308                 return -1;
 309
 310         if (sscanf(pos, "procs_running %u", &running) != 1)
 311                 return -1;
 312
 313         return running;
 314 }
 315
 316 /* return the number of process es in our session, count only until limit */
 317 static int running_processes_in_session(pid_t session, int limit)
 318 {
 319         DIR *dir;
 320         struct dirent *dent;
 321         int running = 0;
 322
 323         dir = opendir("/proc");
 324         if (!dir)
 325                 return -1;
 326
 327         /* read process info from /proc */
 328         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 329                 int f;
 330                 char procdir[64];
 331                 char line[256];
 332                 const char *pos;
 333                 char state;
 334                 pid_t ppid, pgrp, sess;
 335                 int len;
 336
 337                 if (!isdigit(dent->d_name[0]))
 338                         continue;
 339
 340                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 341                 procdir[sizeof(procdir)-1] = '\0';
 342
 343                 f = open(procdir, O_RDONLY);
 344                 if (f == -1)
 345                         continue;
 346
 347                 len = read(f, line, sizeof(line)-1);
 348                 close(f);
 349
 350                 if (len <= 0)
 351                         continue;
 352                 else
 353                         line[len] = '\0';
 354
 355                 /* skip ugly program name */
 356                 pos = strrchr(line, ')') + 2;
 357                 if (pos == NULL)
 358                         continue;
 359
 360                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 361                         continue;
 362
 363                 /* count only processes in our session */
 364                 if (sess != session)
 365                         continue;
 366
 367                 /* count only running, no sleeping processes */
 368                 if (state != 'R')
 369                         continue;
 370
 371                 running++;
 372                 if (limit > 0 && running >= limit)
 373                         break;
 374         }
 375         closedir(dir);
 376
 377         return running;
 378 }
 379
 380 static int compare_devpath(const char *running, const char *waiting)
 381 {
 382         int i;
 383
 384         for (i = 0; i < PATH_SIZE; i++) {
 385                 /* identical device event found */
 386                 if (running[i] == '\0' && waiting[i] == '\0')
 387                         return 1;
 388
 389                 /* parent device event found */
 390                 if (running[i] == '\0' && waiting[i] == '/')
 391                         return 2;
 392
 393                 /* child device event found */
 394                 if (running[i] == '/' && waiting[i] == '\0')
 395                         return 3;
 396
 397                 /* no matching event */
 398                 if (running[i] != waiting[i])
 399                         break;
 400         }
 401
 402         return 0;
 403 }
 404
 405 /* returns still running task for the same device, its parent or its physical device */
 406 static int running_with_devpath(struct uevent_msg *msg, int limit)
 407 {
 408         struct uevent_msg *loop_msg;
 409         int childs_count = 0;
 410
 411         list_for_each_entry(loop_msg, &running_list, node) {
 412                 if (limit && childs_count++ > limit) {
 413                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 414                         return 1;
 415                 }
 416
 417                 /* return running parent/child device event */
 418                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 419                         dbg("%llu, child device event still running %llu (%s)",
 420                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 421                         return 2;
 422                 }
 423
 424                 /* return running physical device event */
 425                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 426                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 427                                 dbg("%llu, physical device event still running %llu (%s)",
 428                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 429                                 return 3;
 430                         }
 431         }
 432
 433         return 0;
 434 }
 435
 436 /* exec queue management routine executes the events and serializes events in the same sequence */
 437 static void msg_queue_manager(void)
 438 {
 439         struct uevent_msg *loop_msg;
 440         struct uevent_msg *tmp_msg;
 441         int running;
 442
 443         if (list_empty(&exec_list))
 444                 return;
 445
 446         running = running_processes();
 447         dbg("%d processes runnning on system", running);
 448         if (running < 0)
 449                 running = max_childs_running;
 450
 451         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 452                 /* check running processes in our session and possibly throttle */
 453                 if (running >= max_childs_running) {
 454                         running = running_processes_in_session(sid, max_childs_running+10);
 455                         dbg("at least %d processes running in session", running);
 456                         if (running >= max_childs_running) {
 457                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 458                                 return;
 459                         }
 460                 }
 461
 462                 /* don't run two processes for the same devpath and wait for the parent*/
 463                 if (running_with_devpath(loop_msg, max_childs)) {
 464                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 465                         continue;
 466                 }
 467
 468                 /* move event to run list */
 469                 list_move_tail(&loop_msg->node, &running_list);
 470                 udev_event_run(loop_msg);
 471                 running++;
 472                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 473         }
 474 }
 475
 476 static struct uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 477 {
 478         int bufpos;
 479         int i;
 480         struct uevent_msg *msg;
 481         int major = 0;
 482         int minor = 0;
 483
 484         msg = malloc(sizeof(struct uevent_msg) + buf_size);
 485         if (msg == NULL)
 486                 return NULL;
 487         memset(msg, 0x00, sizeof(struct uevent_msg) + buf_size);
 488
 489         /* copy environment buffer and reconstruct envp */
 490         memcpy(msg->envbuf, buf, buf_size);
 491         bufpos = 0;
 492         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 493                 int keylen;
 494                 char *key;
 495
 496                 key = &msg->envbuf[bufpos];
 497                 keylen = strlen(key);
 498                 msg->envp[i] = key;
 499                 bufpos += keylen + 1;
 500                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 501
 502                 /* remember some keys for further processing */
 503                 if (strncmp(key, "ACTION=", 7) == 0)
 504                         msg->action = &key[7];
 505                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 506                         msg->devpath = &key[8];
 507                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 508                         msg->subsystem = &key[10];
 509                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 510                         msg->seqnum = strtoull(&key[7], NULL, 10);
 511                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 512                         msg->physdevpath = &key[12];
 513                 else if (strncmp(key, "MAJOR=", 6) == 0)
 514                         major = strtoull(&key[6], NULL, 10);
 515                 else if (strncmp(key, "MINOR=", 6) == 0)
 516                         minor = strtoull(&key[6], NULL, 10);
 517                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 518                         msg->timeout = strtoull(&key[8], NULL, 10);
 519         }
 520         msg->devt = makedev(major, minor);
 521         msg->envp[i++] = "UDEVD_EVENT=1";
 522         msg->envp[i] = NULL;
 523
 524         if (msg->devpath == NULL || msg->action == NULL) {
 525                 info("DEVPATH or ACTION missing, ignore message");
 526                 free(msg);
 527                 return NULL;
 528         }
 529
 530         return msg;
 531 }
 532
 533 /* receive the udevd message from userspace */
 534 static struct uevent_msg *get_udevd_msg(void)
 535 {
 536         static struct udevd_msg usend_msg;
 537         struct uevent_msg *msg;
 538         ssize_t size;
 539         struct msghdr smsg;
 540         struct cmsghdr *cmsg;
 541         struct iovec iov;
 542         struct ucred *cred;
 543         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 544         int envbuf_size;
 545         int *intval;
 546
 547         memset(&usend_msg, 0x00, sizeof(struct udevd_msg));
 548         iov.iov_base = &usend_msg;
 549         iov.iov_len = sizeof(struct udevd_msg);
 550
 551         memset(&smsg, 0x00, sizeof(struct msghdr));
 552         smsg.msg_iov = &iov;
 553         smsg.msg_iovlen = 1;
 554         smsg.msg_control = cred_msg;
 555         smsg.msg_controllen = sizeof(cred_msg);
 556
 557         size = recvmsg(udevd_sock, &smsg, 0);
 558         if (size <  0) {
 559                 if (errno != EINTR)
 560                         err("unable to receive user udevd message: %s", strerror(errno));
 561                 return NULL;
 562         }
 563         cmsg = CMSG_FIRSTHDR(&smsg);
 564         cred = (struct ucred *) CMSG_DATA(cmsg);
 565
 566         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 567                 err("no sender credentials received, message ignored");
 568                 return NULL;
 569         }
 570
 571         if (cred->uid != 0) {
 572                 err("sender uid=%i, message ignored", cred->uid);
 573                 return NULL;
 574         }
 575
 576         if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
 577                 err("message magic '%s' doesn't match, ignore it", usend_msg.magic);
 578                 return NULL;
 579         }
 580
 581         switch (usend_msg.type) {
 582         case UDEVD_UEVENT_UDEVSEND:
 583         case UDEVD_UEVENT_INITSEND:
 584                 info("udevd event message received");
 585                 envbuf_size = size - offsetof(struct udevd_msg, envbuf);
 586                 dbg("envbuf_size=%i", envbuf_size);
 587                 msg = get_msg_from_envbuf(usend_msg.envbuf, envbuf_size);
 588                 if (msg == NULL)
 589                         return NULL;
 590                 msg->type = usend_msg.type;
 591                 return msg;
 592         case UDEVD_STOP_EXEC_QUEUE:
 593                 info("udevd message (STOP_EXEC_QUEUE) received");
 594                 stop_exec_q = 1;
 595                 break;
 596         case UDEVD_START_EXEC_QUEUE:
 597                 info("udevd message (START_EXEC_QUEUE) received");
 598                 stop_exec_q = 0;
 599                 msg_queue_manager();
 600                 break;
 601         case UDEVD_SET_LOG_LEVEL:
 602                 intval = (int *) usend_msg.envbuf;
 603                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 604                 udev_log_priority = *intval;
 605                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 606                 putenv(udev_log);
 607                 break;
 608         case UDEVD_SET_MAX_CHILDS:
 609                 intval = (int *) usend_msg.envbuf;
 610                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 611                 max_childs = *intval;
 612                 break;
 613         case UDEVD_RELOAD_RULES:
 614                 info("udevd message (RELOAD_RULES) received");
 615                 reload_config = 1;
 616                 break;
 617         default:
 618                 dbg("unknown message type");
 619         }
 620         return NULL;
 621 }
 622
 623 /* receive the kernel user event message and do some sanity checks */
 624 static struct uevent_msg *get_netlink_msg(void)
 625 {
 626         struct uevent_msg *msg;
 627         int bufpos;
 628         ssize_t size;
 629         static char buffer[UEVENT_BUFFER_SIZE+512];
 630         char *pos;
 631
 632         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 633         if (size <  0) {
 634                 if (errno != EINTR)
 635                         err("unable to receive kernel netlink message: %s", strerror(errno));
 636                 return NULL;
 637         }
 638
 639         if ((size_t)size > sizeof(buffer)-1)
 640                 size = sizeof(buffer)-1;
 641         buffer[size] = '\0';
 642         dbg("uevent_size=%zi", size);
 643
 644         /* start of event payload */
 645         bufpos = strlen(buffer)+1;
 646         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 647         if (msg == NULL)
 648                 return NULL;
 649         msg->type = UDEVD_UEVENT_NETLINK;
 650
 651         /* validate message */
 652         pos = strchr(buffer, '@');
 653         if (pos == NULL) {
 654                 err("invalid uevent '%s'", buffer);
 655                 free(msg);
 656                 return NULL;
 657         }
 658         pos[0] = '\0';
 659
 660         if (msg->action == NULL) {
 661                 info("no ACTION in payload found, skip event '%s'", buffer);
 662                 free(msg);
 663                 return NULL;
 664         }
 665
 666         if (strcmp(msg->action, buffer) != 0) {
 667                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 668                 free(msg);
 669                 return NULL;
 670         }
 671
 672         return msg;
 673 }
 674
 675 static void asmlinkage sig_handler(int signum)
 676 {
 677         switch (signum) {
 678                 case SIGINT:
 679                 case SIGTERM:
 680                         udev_exit = 1;
 681                         break;
 682                 case SIGCHLD:
 683                         /* set flag, then write to pipe if needed */
 684                         sigchilds_waiting = 1;
 685                         break;
 686                 case SIGHUP:
 687                         reload_config = 1;
 688                         break;
 689         }
 690
 691         /* write to pipe, which will wakeup select() in our mainloop */
 692         write(signal_pipe[WRITE_END], "", 1);
 693 }
 694
 695 static void udev_done(int pid, int exitstatus)
 696 {
 697         /* find msg associated with pid and delete it */
 698         struct uevent_msg *msg;
 699
 700         list_for_each_entry(msg, &running_list, node) {
 701                 if (msg->pid == pid) {
 702                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 703                              exitstatus, time(NULL) - msg->queue_time);
 704                         msg->exitstatus = exitstatus;
 705                         msg_queue_delete(msg);
 706
 707                         /* there may be events waiting with the same devpath */
 708                         run_exec_q = 1;
 709                         return;
 710                 }
 711         }
 712 }
 713
 714 static void reap_sigchilds(void)
 715 {
 716         pid_t pid;
 717         int status;
 718
 719         while (1) {
 720                 pid = waitpid(-1, &status, WNOHANG);
 721                 if (pid <= 0)
 722                         break;
 723                 if (WIFEXITED(status))
 724                         status = WEXITSTATUS(status);
 725                 else if (WIFSIGNALED(status))
 726                         status = WTERMSIG(status) + 128;
 727                 else
 728                         status = 0;
 729                 udev_done(pid, status);
 730         }
 731 }
 732
 733 static int init_udevd_socket(void)
 734 {
 735         struct sockaddr_un saddr;
 736         const int buffersize = 16 * 1024 * 1024;
 737         socklen_t addrlen;
 738         const int feature_on = 1;
 739         int retval;
 740
 741         memset(&saddr, 0x00, sizeof(saddr));
 742         saddr.sun_family = AF_LOCAL;
 743         /* use abstract namespace for socket path */
 744         strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
 745         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 746
 747         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 748         if (udevd_sock == -1) {
 749                 err("error getting socket: %s", strerror(errno));
 750                 return -1;
 751         }
 752
 753         /* set receive buffersize */
 754         setsockopt(udevd_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 755
 756         /* the bind takes care of ensuring only one copy running */
 757         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 758         if (retval < 0) {
 759                 err("bind failed: %s", strerror(errno));
 760                 return -1;
 761         }
 762
 763         /* enable receiving of the sender credentials */
 764         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 765
 766         return 0;
 767 }
 768
 769 static int init_uevent_netlink_sock(void)
 770 {
 771         struct sockaddr_nl snl;
 772         const int buffersize = 16 * 1024 * 1024;
 773         int retval;
 774
 775         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 776         snl.nl_family = AF_NETLINK;
 777         snl.nl_pid = getpid();
 778         snl.nl_groups = 0xffffffff;
 779
 780         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 781         if (uevent_netlink_sock == -1) {
 782                 err("error getting socket: %s", strerror(errno));
 783                 return -1;
 784         }
 785
 786         /* set receive buffersize */
 787         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 788
 789         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 790         if (retval < 0) {
 791                 err("bind failed: %s", strerror(errno));
 792                 close(uevent_netlink_sock);
 793                 uevent_netlink_sock = -1;
 794                 return -1;
 795         }
 796         return 0;
 797 }
 798
 799 int main(int argc, char *argv[], char *envp[])
 800 {
 801         int retval;
 802         int fd;
 803         struct sigaction act;
 804         fd_set readfds;
 805         const char *value;
 806         int daemonize = 0;
 807         int i;
 808         int rc = 0;
 809         int maxfd;
 810
 811         /* redirect std fd's, if the kernel forks us, we don't have them at all */
 812         fd = open("/dev/null", O_RDWR);
 813         if (fd >= 0) {
 814                 if (fd != STDIN_FILENO)
 815                         dup2(fd, STDIN_FILENO);
 816                 if (fd != STDOUT_FILENO)
 817                         dup2(fd, STDOUT_FILENO);
 818                 if (fd != STDERR_FILENO)
 819                         dup2(fd, STDERR_FILENO);
 820                 if (fd > STDERR_FILENO)
 821                         close(fd);
 822         }
 823
 824         logging_init("udevd");
 825         if (fd < 0)
 826                 err("fatal, could not open /dev/null: %s", strerror(errno));
 827
 828         udev_config_init();
 829         dbg("version %s", UDEV_VERSION);
 830
 831         if (getuid() != 0) {
 832                 err("need to be root, exit");
 833                 goto exit;
 834         }
 835
 836         /* parse commandline options */
 837         for (i = 1 ; i < argc; i++) {
 838                 char *arg = argv[i];
 839                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0) {
 840                         info("will daemonize");
 841                         daemonize = 1;
 842                 }
 843                 if (strcmp(arg, "--stop-exec-queue") == 0) {
 844                         info("will not execute events until START_EXEC_QUEUE is received");
 845                         stop_exec_q = 1;
 846                 }
 847         }
 848
 849         /* init sockets to receive events */
 850         if (init_udevd_socket() < 0) {
 851                 if (errno == EADDRINUSE) {
 852                         err("another udevd running, exit");
 853                         rc = 1;
 854                 } else {
 855                         err("error initializing udevd socket: %s", strerror(errno));
 856                         rc = 2;
 857                 }
 858                 goto exit;
 859         }
 860
 861         if (init_uevent_netlink_sock() < 0) {
 862                 err("uevent socket not available");
 863                 rc = 3;
 864                 goto exit;
 865         }
 866
 867         /* parse the rules and keep it in memory */
 868         sysfs_init();
 869         udev_rules_init(&rules, 1);
 870
 871         if (daemonize) {
 872                 pid_t pid;
 873
 874                 pid = fork();
 875                 switch (pid) {
 876                 case 0:
 877                         dbg("daemonized fork running");
 878                         break;
 879                 case -1:
 880                         err("fork of daemon failed: %s", strerror(errno));
 881                         rc = 4;
 882                         goto exit;
 883                 default:
 884                         dbg("child [%u] running, parent exits", pid);
 885                         goto exit;
 886                 }
 887         }
 888
 889         /* set scheduling priority for the daemon */
 890         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 891
 892         chdir("/");
 893         umask(022);
 894
 895         /* become session leader */
 896         sid = setsid();
 897         dbg("our session is %d", sid);
 898
 899         /* OOM_DISABLE == -17 */
 900         fd = open("/proc/self/oom_adj", O_RDWR);
 901         if (fd < 0)
 902                 err("error disabling OOM: %s", strerror(errno));
 903         else {
 904                 write(fd, "-17", 3);
 905                 close(fd);
 906         }
 907
 908         /* setup signal handler pipe */
 909         retval = pipe(signal_pipe);
 910         if (retval < 0) {
 911                 err("error getting pipes: %s", strerror(errno));
 912                 goto exit;
 913         }
 914         retval = fcntl(signal_pipe[READ_END], F_SETFL, O_NONBLOCK);
 915         if (retval < 0) {
 916                 err("error fcntl on read pipe: %s", strerror(errno));
 917                 goto exit;
 918         }
 919         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, O_NONBLOCK);
 920         if (retval < 0) {
 921                 err("error fcntl on write pipe: %s", strerror(errno));
 922                 goto exit;
 923         }
 924
 925         /* set signal handlers */
 926         memset(&act, 0x00, sizeof(struct sigaction));
 927         act.sa_handler = (void (*)(int)) sig_handler;
 928         sigemptyset(&act.sa_mask);
 929         act.sa_flags = SA_RESTART;
 930         sigaction(SIGINT, &act, NULL);
 931         sigaction(SIGTERM, &act, NULL);
 932         sigaction(SIGCHLD, &act, NULL);
 933         sigaction(SIGHUP, &act, NULL);
 934
 935         /* watch rules directory */
 936         inotify_fd = inotify_init();
 937         if (inotify_fd > 0)
 938                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 939
 940         /* maximum limit of forked childs */
 941         value = getenv("UDEVD_MAX_CHILDS");
 942         if (value)
 943                 max_childs = strtoul(value, NULL, 10);
 944         else
 945                 max_childs = UDEVD_MAX_CHILDS;
 946         info("initialize max_childs to %u", max_childs);
 947
 948         /* start to throttle forking if maximum number of _running_ childs is reached */
 949         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
 950         if (value)
 951                 max_childs_running = strtoull(value, NULL, 10);
 952         else
 953                 max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
 954         info("initialize max_childs_running to %u", max_childs_running);
 955
 956         /* clear environment for forked event processes */
 957         clearenv();
 958
 959         /* export log_priority , as called programs may want to follow that setting */
 960         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 961         putenv(udev_log);
 962
 963         maxfd = udevd_sock;
 964         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
 965         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
 966         maxfd = UDEV_MAX(maxfd, inotify_fd);
 967
 968         while (!udev_exit) {
 969                 struct uevent_msg *msg;
 970                 int fdcount;
 971
 972                 FD_ZERO(&readfds);
 973                 FD_SET(signal_pipe[READ_END], &readfds);
 974                 FD_SET(udevd_sock, &readfds);
 975                 FD_SET(uevent_netlink_sock, &readfds);
 976                 if (inotify_fd > 0)
 977                         FD_SET(inotify_fd, &readfds);
 978
 979                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
 980                 if (fdcount < 0) {
 981                         if (errno != EINTR)
 982                                 err("error in select: %s", strerror(errno));
 983                         continue;
 984                 }
 985
 986                 /* get user socket message */
 987                 if (FD_ISSET(udevd_sock, &readfds)) {
 988                         msg = get_udevd_msg();
 989                         if (msg)
 990                                 msg_queue_insert(msg);
 991                 }
 992
 993                 /* get kernel netlink message */
 994                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
 995                         msg = get_netlink_msg();
 996                         if (msg)
 997                                 msg_queue_insert(msg);
 998                 }
 999
1000                 /* received a signal, clear our notification pipe */
1001                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1002                         char buf[256];
1003
1004                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1005                 }
1006
1007                 /* rules directory inotify watch */
1008                 if ((inotify_fd > 0) && FD_ISSET(inotify_fd, &readfds)) {
1009                         int nbytes;
1010
1011                         /* discard all possible events, we can just reload the config */
1012                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1013                                 char *buf;
1014
1015                                 reload_config = 1;
1016                                 buf = malloc(nbytes);
1017                                 if (!buf) {
1018                                         err("error getting buffer for inotify, disable watching");
1019                                         close(inotify_fd);
1020                                         inotify_fd = -1;
1021                                 }
1022                                 read(inotify_fd, buf, nbytes);
1023                                 free(buf);
1024                         }
1025                 }
1026
1027                 /* rules changed, set by inotify or a signal*/
1028                 if (reload_config) {
1029                         reload_config = 0;
1030                         udev_rules_cleanup(&rules);
1031                         udev_rules_init(&rules, 1);
1032                 }
1033
1034                 /* forked child has returned */
1035                 if (sigchilds_waiting) {
1036                         sigchilds_waiting = 0;
1037                         reap_sigchilds();
1038                 }
1039
1040                 if (run_exec_q) {
1041                         run_exec_q = 0;
1042                         if (!stop_exec_q)
1043                                 msg_queue_manager();
1044                 }
1045         }
1046
1047 exit:
1048         udev_rules_cleanup(&rules);
1049         sysfs_cleanup();
1050
1051         if (signal_pipe[READ_END] > 0)
1052                 close(signal_pipe[READ_END]);
1053         if (signal_pipe[WRITE_END] > 0)
1054                 close(signal_pipe[WRITE_END]);
1055
1056         if (udevd_sock > 0)
1057                 close(udevd_sock);
1058         if (inotify_fd > 0)
1059                 close(inotify_fd);
1060         if (uevent_netlink_sock > 0)
1061                 close(uevent_netlink_sock);
1062
1063         logging_close();
1064
1065         return rc;
1066 }