udevd.c

   1 /*
   2  * udevd.c - event listener and serializer
   3  *
   4  * Copyright (C) 2004-2006 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 udevd_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         /* reset to default */
 104         act.sa_handler = SIG_DFL;
 105         sigaction(SIGINT, &act, NULL);
 106         sigaction(SIGTERM, &act, NULL);
 107         sigaction(SIGCHLD, &act, NULL);
 108         sigaction(SIGHUP, &act, NULL);
 109
 110         /* trigger timeout to prevent hanging processes */
 111         alarm(UDEV_ALARM_TIMEOUT);
 112
 113         /* reconstruct event environment from message */
 114         for (i = 0; msg->envp[i]; i++)
 115                 putenv(msg->envp[i]);
 116
 117         udev = udev_device_init();
 118         if (udev == NULL)
 119                 return -1;
 120         strlcpy(udev->action, msg->action, sizeof(udev->action));
 121         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem);
 122         udev->devt = msg->devt;
 123
 124         retval = udev_device_event(&rules, udev);
 125
 126         /* run programs collected by RUN-key*/
 127         if (retval == 0 && !udev->ignore_device && udev_run) {
 128                 struct name_entry *name_loop;
 129
 130                 dbg("executing run list");
 131                 list_for_each_entry(name_loop, &udev->run_list, node) {
 132                         if (strncmp(name_loop->name, "socket:", strlen("socket:")) == 0)
 133                                 pass_env_to_socket(&name_loop->name[strlen("socket:")], udev->dev->devpath, udev->action);
 134                         else {
 135                                 char program[PATH_SIZE];
 136
 137                                 strlcpy(program, name_loop->name, sizeof(program));
 138                                 udev_rules_apply_format(udev, program, sizeof(program));
 139                                 if (run_program(program, udev->dev->subsystem, NULL, 0, NULL,
 140                                                 (udev_log_priority >= LOG_INFO)))
 141                                         retval = -1;
 142                         }
 143                 }
 144         }
 145
 146         udev_device_cleanup(udev);
 147         return retval;
 148 }
 149
 150 enum event_state {
 151         EVENT_QUEUED,
 152         EVENT_FINISHED,
 153         EVENT_FAILED,
 154 };
 155
 156 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 157 {
 158         char filename[PATH_SIZE];
 159         char filename_failed[PATH_SIZE];
 160         char target[PATH_SIZE];
 161         size_t start, end, i;
 162         struct udevd_uevent_msg *loop_msg;
 163
 164         /* add location of queue files */
 165         strlcpy(filename, udev_root, sizeof(filename));
 166         strlcat(filename, "/", sizeof(filename));
 167         start = strlcat(filename, EVENT_QUEUE_DIR, sizeof(filename));
 168         end = strlcat(filename, msg->devpath, sizeof(filename));
 169         if (end > sizeof(filename))
 170                 end = sizeof(filename);
 171
 172         /* replace '/' to transform path into a filename */
 173         for (i = start+1; i < end; i++)
 174                 if (filename[i] == '/')
 175                         filename[i] = PATH_TO_NAME_CHAR;
 176
 177         /* add location of failed files */
 178         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 179         strlcat(filename_failed, "/", sizeof(filename_failed));
 180         start = strlcat(filename_failed, EVENT_FAILED_DIR, sizeof(filename_failed));
 181         end = strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 182         if (end > sizeof(filename_failed))
 183                 end = sizeof(filename_failed);
 184
 185         /* replace '/' to transform path into a filename */
 186         for (i = start+1; i < end; i++)
 187                 if (filename_failed[i] == '/')
 188                         filename_failed[i] = PATH_TO_NAME_CHAR;
 189
 190         switch (state) {
 191         case EVENT_QUEUED:
 192                 unlink(filename_failed);
 193                 delete_path(filename_failed);
 194
 195                 strlcpy(target, sysfs_path, sizeof(target));
 196                 strlcat(target, msg->devpath, sizeof(target));
 197                 create_path(filename);
 198                 symlink(target, filename);
 199                 return;
 200         case EVENT_FINISHED:
 201         case EVENT_FAILED:
 202                 unlink(filename_failed);
 203                 delete_path(filename_failed);
 204
 205                 /* don't remove, if events for the same path are still pending */
 206                 list_for_each_entry(loop_msg, &running_list, node)
 207                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 208                                 return;
 209
 210                 list_for_each_entry(loop_msg, &exec_list, node)
 211                         if (loop_msg->devpath && strcmp(loop_msg->devpath, msg->devpath) == 0)
 212                                 return;
 213
 214                 /* move failed events to the failed directory */
 215                 if (state == EVENT_FAILED) {
 216                         create_path(filename_failed);
 217                         rename(filename, filename_failed);
 218                 } else {
 219                         unlink(filename);
 220                 }
 221
 222                 /* clean up the queue directory */
 223                 delete_path(filename);
 224
 225                 return;
 226         }
 227 }
 228
 229 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 230 {
 231         list_del(&msg->node);
 232
 233         /* mark as failed, if add event returns non-zero */
 234         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 235                 export_event_state(msg, EVENT_FAILED);
 236         else
 237                 export_event_state(msg, EVENT_FINISHED);
 238
 239         free(msg);
 240 }
 241
 242 static void udev_event_run(struct udevd_uevent_msg *msg)
 243 {
 244         pid_t pid;
 245         int retval;
 246
 247         pid = fork();
 248         switch (pid) {
 249         case 0:
 250                 /* child */
 251                 close(uevent_netlink_sock);
 252                 close(udevd_sock);
 253                 if (inotify_fd >= 0)
 254                         close(inotify_fd);
 255                 close(signal_pipe[READ_END]);
 256                 close(signal_pipe[WRITE_END]);
 257                 logging_close();
 258
 259                 logging_init("udevd-event");
 260                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 261
 262                 retval = udev_event_process(msg);
 263                 info("seq %llu finished", msg->seqnum);
 264
 265                 logging_close();
 266                 if (retval)
 267                         exit(1);
 268                 exit(0);
 269         case -1:
 270                 err("fork of child failed: %s", strerror(errno));
 271                 msg_queue_delete(msg);
 272                 break;
 273         default:
 274                 /* get SIGCHLD in main loop */
 275                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 276                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 277                 msg->pid = pid;
 278         }
 279 }
 280
 281 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 282 {
 283         char filename[PATH_SIZE];
 284         int fd;
 285
 286         msg->queue_time = time(NULL);
 287
 288         strlcpy(filename, udev_root, sizeof(filename));
 289         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 290         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 291         if (fd >= 0) {
 292                 char str[32];
 293                 int len;
 294
 295                 len = sprintf(str, "%llu\n", msg->seqnum);
 296                 write(fd, str, len);
 297                 close(fd);
 298         }
 299
 300         export_event_state(msg, EVENT_QUEUED);
 301
 302         /* run all events with a timeout set immediately */
 303         if (msg->timeout != 0) {
 304                 list_add_tail(&msg->node, &running_list);
 305                 udev_event_run(msg);
 306                 return;
 307         }
 308
 309         list_add_tail(&msg->node, &exec_list);
 310         run_exec_q = 1;
 311 }
 312
 313 /* runs event and removes event from run queue when finished */
 314 static int running_processes(void)
 315 {
 316         int f;
 317         char buf[32768];
 318         int len;
 319         int running;
 320         const char *pos;
 321
 322         f = open("/proc/stat", O_RDONLY);
 323         if (f == -1)
 324                 return -1;
 325
 326         len = read(f, buf, sizeof(buf)-1);
 327         close(f);
 328
 329         if (len <= 0)
 330                 return -1;
 331         else
 332                 buf[len] = '\0';
 333
 334         pos = strstr(buf, "procs_running ");
 335         if (pos == NULL)
 336                 return -1;
 337
 338         if (sscanf(pos, "procs_running %u", &running) != 1)
 339                 return -1;
 340
 341         return running;
 342 }
 343
 344 /* return the number of process es in our session, count only until limit */
 345 static int running_processes_in_session(pid_t session, int limit)
 346 {
 347         DIR *dir;
 348         struct dirent *dent;
 349         int running = 0;
 350
 351         dir = opendir("/proc");
 352         if (!dir)
 353                 return -1;
 354
 355         /* read process info from /proc */
 356         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 357                 int f;
 358                 char procdir[64];
 359                 char line[256];
 360                 const char *pos;
 361                 char state;
 362                 pid_t ppid, pgrp, sess;
 363                 int len;
 364
 365                 if (!isdigit(dent->d_name[0]))
 366                         continue;
 367
 368                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 369                 procdir[sizeof(procdir)-1] = '\0';
 370
 371                 f = open(procdir, O_RDONLY);
 372                 if (f == -1)
 373                         continue;
 374
 375                 len = read(f, line, sizeof(line)-1);
 376                 close(f);
 377
 378                 if (len <= 0)
 379                         continue;
 380                 else
 381                         line[len] = '\0';
 382
 383                 /* skip ugly program name */
 384                 pos = strrchr(line, ')') + 2;
 385                 if (pos == NULL)
 386                         continue;
 387
 388                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 389                         continue;
 390
 391                 /* count only processes in our session */
 392                 if (sess != session)
 393                         continue;
 394
 395                 /* count only running, no sleeping processes */
 396                 if (state != 'R')
 397                         continue;
 398
 399                 running++;
 400                 if (limit > 0 && running >= limit)
 401                         break;
 402         }
 403         closedir(dir);
 404
 405         return running;
 406 }
 407
 408 static int compare_devpath(const char *running, const char *waiting)
 409 {
 410         int i;
 411
 412         for (i = 0; i < PATH_SIZE; i++) {
 413                 /* identical device event found */
 414                 if (running[i] == '\0' && waiting[i] == '\0')
 415                         return 1;
 416
 417                 /* parent device event found */
 418                 if (running[i] == '\0' && waiting[i] == '/')
 419                         return 2;
 420
 421                 /* child device event found */
 422                 if (running[i] == '/' && waiting[i] == '\0')
 423                         return 3;
 424
 425                 /* no matching event */
 426                 if (running[i] != waiting[i])
 427                         break;
 428         }
 429
 430         return 0;
 431 }
 432
 433 /* returns still running task for the same device, its parent or its physical device */
 434 static int running_with_devpath(struct udevd_uevent_msg *msg, int limit)
 435 {
 436         struct udevd_uevent_msg *loop_msg;
 437         int childs_count = 0;
 438
 439         list_for_each_entry(loop_msg, &running_list, node) {
 440                 if (limit && childs_count++ > limit) {
 441                         dbg("%llu, maximum number (%i) of child reached", msg->seqnum, childs_count);
 442                         return 1;
 443                 }
 444
 445                 /* return running parent/child device event */
 446                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 447                         dbg("%llu, child device event still running %llu (%s)",
 448                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 449                         return 2;
 450                 }
 451
 452                 /* return running physical device event */
 453                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 454                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 455                                 dbg("%llu, physical device event still running %llu (%s)",
 456                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 457                                 return 3;
 458                         }
 459         }
 460
 461         return 0;
 462 }
 463
 464 /* exec queue management routine executes the events and serializes events in the same sequence */
 465 static void msg_queue_manager(void)
 466 {
 467         struct udevd_uevent_msg *loop_msg;
 468         struct udevd_uevent_msg *tmp_msg;
 469         int running;
 470
 471         if (list_empty(&exec_list))
 472                 return;
 473
 474         running = running_processes();
 475         dbg("%d processes runnning on system", running);
 476         if (running < 0)
 477                 running = max_childs_running;
 478
 479         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 480                 /* check running processes in our session and possibly throttle */
 481                 if (running >= max_childs_running) {
 482                         running = running_processes_in_session(sid, max_childs_running+10);
 483                         dbg("at least %d processes running in session", running);
 484                         if (running >= max_childs_running) {
 485                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 486                                 return;
 487                         }
 488                 }
 489
 490                 /* don't run two processes for the same devpath and wait for the parent*/
 491                 if (running_with_devpath(loop_msg, max_childs)) {
 492                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 493                         continue;
 494                 }
 495
 496                 /* move event to run list */
 497                 list_move_tail(&loop_msg->node, &running_list);
 498                 udev_event_run(loop_msg);
 499                 running++;
 500                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 501         }
 502 }
 503
 504 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 505 {
 506         int bufpos;
 507         int i;
 508         struct udevd_uevent_msg *msg;
 509         int major = 0;
 510         int minor = 0;
 511
 512         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 513         if (msg == NULL)
 514                 return NULL;
 515         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 516
 517         /* copy environment buffer and reconstruct envp */
 518         memcpy(msg->envbuf, buf, buf_size);
 519         bufpos = 0;
 520         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 521                 int keylen;
 522                 char *key;
 523
 524                 key = &msg->envbuf[bufpos];
 525                 keylen = strlen(key);
 526                 msg->envp[i] = key;
 527                 bufpos += keylen + 1;
 528                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 529
 530                 /* remember some keys for further processing */
 531                 if (strncmp(key, "ACTION=", 7) == 0)
 532                         msg->action = &key[7];
 533                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 534                         msg->devpath = &key[8];
 535                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 536                         msg->subsystem = &key[10];
 537                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 538                         msg->seqnum = strtoull(&key[7], NULL, 10);
 539                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 540                         msg->physdevpath = &key[12];
 541                 else if (strncmp(key, "MAJOR=", 6) == 0)
 542                         major = strtoull(&key[6], NULL, 10);
 543                 else if (strncmp(key, "MINOR=", 6) == 0)
 544                         minor = strtoull(&key[6], NULL, 10);
 545                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 546                         msg->timeout = strtoull(&key[8], NULL, 10);
 547         }
 548         msg->devt = makedev(major, minor);
 549         msg->envp[i++] = "UDEVD_EVENT=1";
 550         msg->envp[i] = NULL;
 551
 552         if (msg->devpath == NULL || msg->action == NULL) {
 553                 info("DEVPATH or ACTION missing, ignore message");
 554                 free(msg);
 555                 return NULL;
 556         }
 557         return msg;
 558 }
 559
 560 /* receive the udevd message from userspace */
 561 static void get_ctrl_msg(void)
 562 {
 563         struct udevd_ctrl_msg ctrl_msg;
 564         ssize_t size;
 565         struct msghdr smsg;
 566         struct cmsghdr *cmsg;
 567         struct iovec iov;
 568         struct ucred *cred;
 569         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 570         int *intval;
 571
 572         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 573         iov.iov_base = &ctrl_msg;
 574         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 575
 576         memset(&smsg, 0x00, sizeof(struct msghdr));
 577         smsg.msg_iov = &iov;
 578         smsg.msg_iovlen = 1;
 579         smsg.msg_control = cred_msg;
 580         smsg.msg_controllen = sizeof(cred_msg);
 581
 582         size = recvmsg(udevd_sock, &smsg, 0);
 583         if (size <  0) {
 584                 if (errno != EINTR)
 585                         err("unable to receive user udevd message: %s", strerror(errno));
 586                 return;
 587         }
 588         cmsg = CMSG_FIRSTHDR(&smsg);
 589         cred = (struct ucred *) CMSG_DATA(cmsg);
 590
 591         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 592                 err("no sender credentials received, message ignored");
 593                 return;
 594         }
 595
 596         if (cred->uid != 0) {
 597                 err("sender uid=%i, message ignored", cred->uid);
 598                 return;
 599         }
 600
 601         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 602                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 603                 return;
 604         }
 605
 606         switch (ctrl_msg.type) {
 607         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 608                 info("udevd message (STOP_EXEC_QUEUE) received");
 609                 stop_exec_q = 1;
 610                 break;
 611         case UDEVD_CTRL_START_EXEC_QUEUE:
 612                 info("udevd message (START_EXEC_QUEUE) received");
 613                 stop_exec_q = 0;
 614                 msg_queue_manager();
 615                 break;
 616         case UDEVD_CTRL_SET_LOG_LEVEL:
 617                 intval = (int *) ctrl_msg.buf;
 618                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 619                 udev_log_priority = *intval;
 620                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 621                 putenv(udev_log);
 622                 break;
 623         case UDEVD_CTRL_SET_MAX_CHILDS:
 624                 intval = (int *) ctrl_msg.buf;
 625                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 626                 max_childs = *intval;
 627                 break;
 628         case UDEVD_CTRL_RELOAD_RULES:
 629                 info("udevd message (RELOAD_RULES) received");
 630                 reload_config = 1;
 631                 break;
 632         default:
 633                 dbg("unknown message type");
 634         }
 635 }
 636
 637 /* receive the kernel user event message and do some sanity checks */
 638 static struct udevd_uevent_msg *get_netlink_msg(void)
 639 {
 640         struct udevd_uevent_msg *msg;
 641         int bufpos;
 642         ssize_t size;
 643         static char buffer[UEVENT_BUFFER_SIZE+512];
 644         char *pos;
 645
 646         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 647         if (size <  0) {
 648                 if (errno != EINTR)
 649                         err("unable to receive kernel netlink message: %s", strerror(errno));
 650                 return NULL;
 651         }
 652
 653         if ((size_t)size > sizeof(buffer)-1)
 654                 size = sizeof(buffer)-1;
 655         buffer[size] = '\0';
 656         dbg("uevent_size=%zi", size);
 657
 658         /* start of event payload */
 659         bufpos = strlen(buffer)+1;
 660         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 661         if (msg == NULL)
 662                 return NULL;
 663
 664         /* validate message */
 665         pos = strchr(buffer, '@');
 666         if (pos == NULL) {
 667                 err("invalid uevent '%s'", buffer);
 668                 free(msg);
 669                 return NULL;
 670         }
 671         pos[0] = '\0';
 672
 673         if (msg->action == NULL) {
 674                 info("no ACTION in payload found, skip event '%s'", buffer);
 675                 free(msg);
 676                 return NULL;
 677         }
 678
 679         if (strcmp(msg->action, buffer) != 0) {
 680                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 681                 free(msg);
 682                 return NULL;
 683         }
 684
 685         return msg;
 686 }
 687
 688 static void asmlinkage sig_handler(int signum)
 689 {
 690         switch (signum) {
 691                 case SIGINT:
 692                 case SIGTERM:
 693                         udev_exit = 1;
 694                         break;
 695                 case SIGCHLD:
 696                         /* set flag, then write to pipe if needed */
 697                         sigchilds_waiting = 1;
 698                         break;
 699                 case SIGHUP:
 700                         reload_config = 1;
 701                         break;
 702         }
 703
 704         /* write to pipe, which will wakeup select() in our mainloop */
 705         write(signal_pipe[WRITE_END], "", 1);
 706 }
 707
 708 static void udev_done(int pid, int exitstatus)
 709 {
 710         /* find msg associated with pid and delete it */
 711         struct udevd_uevent_msg *msg;
 712
 713         list_for_each_entry(msg, &running_list, node) {
 714                 if (msg->pid == pid) {
 715                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 716                              exitstatus, time(NULL) - msg->queue_time);
 717                         msg->exitstatus = exitstatus;
 718                         msg_queue_delete(msg);
 719
 720                         /* there may be events waiting with the same devpath */
 721                         run_exec_q = 1;
 722                         return;
 723                 }
 724         }
 725 }
 726
 727 static void reap_sigchilds(void)
 728 {
 729         pid_t pid;
 730         int status;
 731
 732         while (1) {
 733                 pid = waitpid(-1, &status, WNOHANG);
 734                 if (pid <= 0)
 735                         break;
 736                 if (WIFEXITED(status))
 737                         status = WEXITSTATUS(status);
 738                 else if (WIFSIGNALED(status))
 739                         status = WTERMSIG(status) + 128;
 740                 else
 741                         status = 0;
 742                 udev_done(pid, status);
 743         }
 744 }
 745
 746 static int init_udevd_socket(void)
 747 {
 748         struct sockaddr_un saddr;
 749         const int buffersize = 16 * 1024 * 1024;
 750         socklen_t addrlen;
 751         const int feature_on = 1;
 752         int retval;
 753
 754         memset(&saddr, 0x00, sizeof(saddr));
 755         saddr.sun_family = AF_LOCAL;
 756         /* use abstract namespace for socket path */
 757         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 758         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 759
 760         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 761         if (udevd_sock == -1) {
 762                 err("error getting socket: %s", strerror(errno));
 763                 return -1;
 764         }
 765
 766         /* set receive buffersize */
 767         setsockopt(udevd_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 768
 769         /* the bind takes care of ensuring only one copy running */
 770         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 771         if (retval < 0) {
 772                 err("bind failed: %s", strerror(errno));
 773                 return -1;
 774         }
 775
 776         /* enable receiving of the sender credentials */
 777         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 778
 779         return 0;
 780 }
 781
 782 static int init_uevent_netlink_sock(void)
 783 {
 784         struct sockaddr_nl snl;
 785         const int buffersize = 16 * 1024 * 1024;
 786         int retval;
 787
 788         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 789         snl.nl_family = AF_NETLINK;
 790         snl.nl_pid = getpid();
 791         snl.nl_groups = 1;
 792
 793         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 794         if (uevent_netlink_sock == -1) {
 795                 err("error getting socket: %s", strerror(errno));
 796                 return -1;
 797         }
 798
 799         /* set receive buffersize */
 800         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 801
 802         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 803         if (retval < 0) {
 804                 err("bind failed: %s", strerror(errno));
 805                 close(uevent_netlink_sock);
 806                 uevent_netlink_sock = -1;
 807                 return -1;
 808         }
 809         return 0;
 810 }
 811
 812 static void export_initial_seqnum(void)
 813 {
 814         char filename[PATH_SIZE];
 815         int fd;
 816         char seqnum[32];
 817         ssize_t len = 0;
 818
 819         strlcpy(filename, sysfs_path, sizeof(filename));
 820         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 821         fd = open(filename, O_RDONLY);
 822         if (fd >= 0) {
 823                 len = read(fd, seqnum, sizeof(seqnum)-1);
 824                 close(fd);
 825         }
 826         if (len <= 0) {
 827                 strcpy(seqnum, "0\n");
 828                 len = 3;
 829         }
 830         strlcpy(filename, udev_root, sizeof(filename));
 831         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 832         create_path(filename);
 833         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 834         if (fd >= 0) {
 835                 write(fd, seqnum, len);
 836                 close(fd);
 837         }
 838 }
 839
 840 int main(int argc, char *argv[], char *envp[])
 841 {
 842         int retval;
 843         int fd;
 844         struct sigaction act;
 845         fd_set readfds;
 846         const char *value;
 847         int daemonize = 0;
 848         int i;
 849         int rc = 0;
 850         int maxfd;
 851
 852         /* redirect std fd's, if the kernel forks us, we don't have them at all */
 853         fd = open("/dev/null", O_RDWR);
 854         if (fd >= 0) {
 855                 if (fd != STDIN_FILENO)
 856                         dup2(fd, STDIN_FILENO);
 857                 if (fd != STDOUT_FILENO)
 858                         dup2(fd, STDOUT_FILENO);
 859                 if (fd != STDERR_FILENO)
 860                         dup2(fd, STDERR_FILENO);
 861                 if (fd > STDERR_FILENO)
 862                         close(fd);
 863         }
 864
 865         logging_init("udevd");
 866         if (fd < 0)
 867                 err("fatal, could not open /dev/null: %s", strerror(errno));
 868
 869         udev_config_init();
 870         dbg("version %s", UDEV_VERSION);
 871
 872         if (getuid() != 0) {
 873                 err("need to be root, exit");
 874                 goto exit;
 875         }
 876
 877         /* parse commandline options */
 878         for (i = 1 ; i < argc; i++) {
 879                 char *arg = argv[i];
 880                 if (strcmp(arg, "--daemon") == 0 || strcmp(arg, "-d") == 0) {
 881                         info("will daemonize");
 882                         daemonize = 1;
 883                 }
 884                 if (strcmp(arg, "--stop-exec-queue") == 0) {
 885                         info("will not execute events until START_EXEC_QUEUE is received");
 886                         stop_exec_q = 1;
 887                 }
 888         }
 889
 890         /* init sockets to receive events */
 891         if (init_udevd_socket() < 0) {
 892                 if (errno == EADDRINUSE) {
 893                         err("another udevd running, exit");
 894                         rc = 1;
 895                 } else {
 896                         err("error initializing udevd socket: %s", strerror(errno));
 897                         rc = 2;
 898                 }
 899                 goto exit;
 900         }
 901
 902         if (init_uevent_netlink_sock() < 0) {
 903                 err("uevent socket not available");
 904                 rc = 3;
 905                 goto exit;
 906         }
 907
 908         /* parse the rules and keep it in memory */
 909         sysfs_init();
 910         udev_rules_init(&rules, 1);
 911
 912         export_initial_seqnum();
 913
 914         if (daemonize) {
 915                 pid_t pid;
 916
 917                 pid = fork();
 918                 switch (pid) {
 919                 case 0:
 920                         dbg("daemonized fork running");
 921                         break;
 922                 case -1:
 923                         err("fork of daemon failed: %s", strerror(errno));
 924                         rc = 4;
 925                         goto exit;
 926                 default:
 927                         dbg("child [%u] running, parent exits", pid);
 928                         goto exit;
 929                 }
 930         }
 931
 932         /* set scheduling priority for the daemon */
 933         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 934
 935         chdir("/");
 936         umask(022);
 937
 938         /* become session leader */
 939         sid = setsid();
 940         dbg("our session is %d", sid);
 941
 942         /* OOM_DISABLE == -17 */
 943         fd = open("/proc/self/oom_adj", O_RDWR);
 944         if (fd < 0)
 945                 err("error disabling OOM: %s", strerror(errno));
 946         else {
 947                 write(fd, "-17", 3);
 948                 close(fd);
 949         }
 950
 951         /* setup signal handler pipe */
 952         retval = pipe(signal_pipe);
 953         if (retval < 0) {
 954                 err("error getting pipes: %s", strerror(errno));
 955                 goto exit;
 956         }
 957
 958         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
 959         if (retval < 0) {
 960                 err("error fcntl on read pipe: %s", strerror(errno));
 961                 goto exit;
 962         }
 963         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
 964         if (retval < 0) {
 965                 err("error fcntl on read pipe: %s", strerror(errno));
 966                 goto exit;
 967         }
 968
 969         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
 970         if (retval < 0) {
 971                 err("error fcntl on write pipe: %s", strerror(errno));
 972                 goto exit;
 973         }
 974         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
 975         if (retval < 0) {
 976                 err("error fcntl on write pipe: %s", strerror(errno));
 977                 goto exit;
 978         }
 979
 980         /* set signal handlers */
 981         memset(&act, 0x00, sizeof(struct sigaction));
 982         act.sa_handler = (void (*)(int)) sig_handler;
 983         sigemptyset(&act.sa_mask);
 984         act.sa_flags = SA_RESTART;
 985         sigaction(SIGINT, &act, NULL);
 986         sigaction(SIGTERM, &act, NULL);
 987         sigaction(SIGCHLD, &act, NULL);
 988         sigaction(SIGHUP, &act, NULL);
 989
 990         /* watch rules directory */
 991         inotify_fd = inotify_init();
 992         if (inotify_fd >= 0)
 993                 inotify_add_watch(inotify_fd, udev_rules_filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 994         else if (errno == ENOSYS)
 995                 err("the kernel does not support inotify, udevd can't monitor configuration file changes");
 996         else
 997                 err("inotify_init failed: %s", strerror(errno));
 998
 999         /* maximum limit of forked childs */
1000         value = getenv("UDEVD_MAX_CHILDS");
1001         if (value)
1002                 max_childs = strtoul(value, NULL, 10);
1003         else
1004                 max_childs = UDEVD_MAX_CHILDS;
1005         info("initialize max_childs to %u", max_childs);
1006
1007         /* start to throttle forking if maximum number of _running_ childs is reached */
1008         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1009         if (value)
1010                 max_childs_running = strtoull(value, NULL, 10);
1011         else
1012                 max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1013         info("initialize max_childs_running to %u", max_childs_running);
1014
1015         /* clear environment for forked event processes */
1016         clearenv();
1017
1018         /* export log_priority , as called programs may want to follow that setting */
1019         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1020         putenv(udev_log);
1021
1022         maxfd = udevd_sock;
1023         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1024         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1025         maxfd = UDEV_MAX(maxfd, inotify_fd);
1026
1027         while (!udev_exit) {
1028                 struct udevd_uevent_msg *msg;
1029                 int fdcount;
1030
1031                 FD_ZERO(&readfds);
1032                 FD_SET(signal_pipe[READ_END], &readfds);
1033                 FD_SET(udevd_sock, &readfds);
1034                 FD_SET(uevent_netlink_sock, &readfds);
1035                 if (inotify_fd >= 0)
1036                         FD_SET(inotify_fd, &readfds);
1037
1038                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1039                 if (fdcount < 0) {
1040                         if (errno != EINTR)
1041                                 err("error in select: %s", strerror(errno));
1042                         continue;
1043                 }
1044
1045                 /* get control message */
1046                 if (FD_ISSET(udevd_sock, &readfds))
1047                         get_ctrl_msg();
1048
1049                 /* get netlink message */
1050                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1051                         msg = get_netlink_msg();
1052                         if (msg)
1053                                 msg_queue_insert(msg);
1054                 }
1055
1056                 /* received a signal, clear our notification pipe */
1057                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1058                         char buf[256];
1059
1060                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1061                 }
1062
1063                 /* rules directory inotify watch */
1064                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1065                         int nbytes;
1066
1067                         /* discard all possible events, we can just reload the config */
1068                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes) {
1069                                 char *buf;
1070
1071                                 reload_config = 1;
1072                                 buf = malloc(nbytes);
1073                                 if (!buf) {
1074                                         err("error getting buffer for inotify, disable watching");
1075                                         close(inotify_fd);
1076                                         inotify_fd = -1;
1077                                 }
1078                                 read(inotify_fd, buf, nbytes);
1079                                 free(buf);
1080                         }
1081                 }
1082
1083                 /* rules changed, set by inotify or a signal*/
1084                 if (reload_config) {
1085                         reload_config = 0;
1086                         udev_rules_cleanup(&rules);
1087                         udev_rules_init(&rules, 1);
1088                 }
1089
1090                 /* forked child has returned */
1091                 if (sigchilds_waiting) {
1092                         sigchilds_waiting = 0;
1093                         reap_sigchilds();
1094                 }
1095
1096                 if (run_exec_q) {
1097                         run_exec_q = 0;
1098                         if (!stop_exec_q)
1099                                 msg_queue_manager();
1100                 }
1101         }
1102
1103 exit:
1104         udev_rules_cleanup(&rules);
1105         sysfs_cleanup();
1106
1107         if (signal_pipe[READ_END] >= 0)
1108                 close(signal_pipe[READ_END]);
1109         if (signal_pipe[WRITE_END] >= 0)
1110                 close(signal_pipe[WRITE_END]);
1111
1112         if (udevd_sock >= 0)
1113                 close(udevd_sock);
1114         if (inotify_fd >= 0)
1115                 close(inotify_fd);
1116         if (uevent_netlink_sock >= 0)
1117                 close(uevent_netlink_sock);
1118
1119         logging_close();
1120
1121         return rc;
1122 }