udevd.c

   1 /*
   2  * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
   3  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   4  *
   5  *      This program is free software; you can redistribute it and/or modify it
   6  *      under the terms of the GNU General Public License as published by the
   7  *      Free Software Foundation version 2 of the License.
   8  *
   9  *      This program is distributed in the hope that it will be useful, but
  10  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *      General Public License for more details.
  13  *
  14  *      You should have received a copy of the GNU General Public License along
  15  *      with this program; if not, write to the Free Software Foundation, Inc.,
  16  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  *
  18  */
  19
  20 #include <stddef.h>
  21 #include <signal.h>
  22 #include <unistd.h>
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <dirent.h>
  29 #include <fcntl.h>
  30 #include <syslog.h>
  31 #include <time.h>
  32 #include <getopt.h>
  33 #include <sys/select.h>
  34 #include <sys/wait.h>
  35 #include <sys/types.h>
  36 #include <sys/socket.h>
  37 #include <sys/un.h>
  38 #include <sys/stat.h>
  39 #include <sys/ioctl.h>
  40 #include <linux/types.h>
  41 #include <linux/netlink.h>
  42
  43 #include "udev.h"
  44 #include "udev_rules.h"
  45 #include "udevd.h"
  46 #include "udev_selinux.h"
  47
  48 static int debug_trace;
  49 static int verbose;
  50
  51 static struct udev_rules rules;
  52 static int udevd_sock = -1;
  53 static int uevent_netlink_sock = -1;
  54 static int inotify_fd = -1;
  55 static pid_t sid;
  56
  57 static int signal_pipe[2] = {-1, -1};
  58 static volatile int sigchilds_waiting;
  59 static volatile int udev_exit;
  60 static volatile int reload_config;
  61 static int run_exec_q;
  62 static int stop_exec_q;
  63 static int max_childs;
  64 static int max_childs_running;
  65 static char udev_log[32];
  66
  67 static LIST_HEAD(exec_list);
  68 static LIST_HEAD(running_list);
  69
  70
  71 #ifdef USE_LOG
  72 void log_message(int priority, const char *format, ...)
  73 {
  74         va_list args;
  75
  76         if (priority > udev_log_priority)
  77                 return;
  78
  79         if (verbose) {
  80                 printf("[%d] ", (int) getpid());
  81                 va_start(args, format);
  82                 vprintf(format, args);
  83                 va_end(args);
  84                 printf("\n");
  85         } else {
  86                 va_start(args, format);
  87                 vsyslog(priority, format, args);
  88                 va_end(args);
  89         }
  90 }
  91
  92 #endif
  93
  94 static void asmlinkage udev_event_sig_handler(int signum)
  95 {
  96         if (signum == SIGALRM)
  97                 exit(1);
  98 }
  99
 100 static int udev_event_process(struct udevd_uevent_msg *msg)
 101 {
 102         struct sigaction act;
 103         struct udevice *udev;
 104         int i;
 105         int retval;
 106
 107         /* set signal handlers */
 108         memset(&act, 0x00, sizeof(act));
 109         act.sa_handler = (void (*)(int)) udev_event_sig_handler;
 110         sigemptyset (&act.sa_mask);
 111         act.sa_flags = 0;
 112         sigaction(SIGALRM, &act, NULL);
 113
 114         /* reset to default */
 115         act.sa_handler = SIG_DFL;
 116         sigaction(SIGINT, &act, NULL);
 117         sigaction(SIGTERM, &act, NULL);
 118         sigaction(SIGCHLD, &act, NULL);
 119         sigaction(SIGHUP, &act, NULL);
 120
 121         /* trigger timeout to prevent hanging processes */
 122         alarm(UDEV_ALARM_TIMEOUT);
 123
 124         /* reconstruct event environment from message */
 125         for (i = 0; msg->envp[i]; i++)
 126                 putenv(msg->envp[i]);
 127
 128         udev = udev_device_init(NULL);
 129         if (udev == NULL)
 130                 return -1;
 131         strlcpy(udev->action, msg->action, sizeof(udev->action));
 132         sysfs_device_set_values(udev->dev, msg->devpath, msg->subsystem, msg->driver);
 133         udev->devpath_old = msg->devpath_old;
 134         udev->devt = msg->devt;
 135
 136         retval = udev_device_event(&rules, udev);
 137
 138         /* run programs collected by RUN-key*/
 139         if (retval == 0 && !udev->ignore_device && udev_run)
 140                 retval = udev_rules_run(udev);
 141
 142         udev_device_cleanup(udev);
 143         return retval;
 144 }
 145
 146 enum event_state {
 147         EVENT_QUEUED,
 148         EVENT_FINISHED,
 149         EVENT_FAILED,
 150 };
 151
 152 static void export_event_state(struct udevd_uevent_msg *msg, enum event_state state)
 153 {
 154         char filename[PATH_SIZE];
 155         char filename_failed[PATH_SIZE];
 156         size_t start;
 157
 158         /* location of queue file */
 159         snprintf(filename, sizeof(filename), "%s/"EVENT_QUEUE_DIR"/%llu", udev_root, msg->seqnum);
 160
 161         /* location of failed file */
 162         strlcpy(filename_failed, udev_root, sizeof(filename_failed));
 163         strlcat(filename_failed, "/", sizeof(filename_failed));
 164         start = strlcat(filename_failed, EVENT_FAILED_DIR"/", sizeof(filename_failed));
 165         strlcat(filename_failed, msg->devpath, sizeof(filename_failed));
 166         path_encode(&filename_failed[start], sizeof(filename_failed) - start);
 167
 168         switch (state) {
 169         case EVENT_QUEUED:
 170                 unlink(filename_failed);
 171                 delete_path(filename_failed);
 172
 173                 create_path(filename);
 174                 symlink(msg->devpath, filename);
 175                 break;
 176         case EVENT_FINISHED:
 177                 if (msg->devpath_old != NULL) {
 178                         /* "move" event - rename failed file to current name, do not delete failed */
 179                         char filename_failed_old[PATH_SIZE];
 180
 181                         strlcpy(filename_failed_old, udev_root, sizeof(filename_failed_old));
 182                         strlcat(filename_failed_old, "/", sizeof(filename_failed_old));
 183                         start = strlcat(filename_failed_old, EVENT_FAILED_DIR"/", sizeof(filename_failed_old));
 184                         strlcat(filename_failed_old, msg->devpath_old, sizeof(filename_failed_old));
 185                         path_encode(&filename_failed_old[start], sizeof(filename) - start);
 186
 187                         if (rename(filename_failed_old, filename_failed) == 0)
 188                                 info("renamed devpath, moved failed state of '%s' to %s'",
 189                                      msg->devpath_old, msg->devpath);
 190                 } else {
 191                         unlink(filename_failed);
 192                         delete_path(filename_failed);
 193                 }
 194
 195                 unlink(filename);
 196                 delete_path(filename);
 197                 break;
 198         case EVENT_FAILED:
 199                 /* move failed event to the failed directory */
 200                 create_path(filename_failed);
 201                 rename(filename, filename_failed);
 202
 203                 /* clean up possibly empty queue directory */
 204                 delete_path(filename);
 205                 break;
 206         }
 207
 208         return;
 209 }
 210
 211 static void msg_queue_delete(struct udevd_uevent_msg *msg)
 212 {
 213         list_del(&msg->node);
 214
 215         /* mark as failed, if "add" event returns non-zero */
 216         if (msg->exitstatus && strcmp(msg->action, "add") == 0)
 217                 export_event_state(msg, EVENT_FAILED);
 218         else
 219                 export_event_state(msg, EVENT_FINISHED);
 220
 221         free(msg);
 222 }
 223
 224 static void udev_event_run(struct udevd_uevent_msg *msg)
 225 {
 226         pid_t pid;
 227         int retval;
 228
 229         pid = fork();
 230         switch (pid) {
 231         case 0:
 232                 /* child */
 233                 close(uevent_netlink_sock);
 234                 close(udevd_sock);
 235                 if (inotify_fd >= 0)
 236                         close(inotify_fd);
 237                 close(signal_pipe[READ_END]);
 238                 close(signal_pipe[WRITE_END]);
 239                 logging_close();
 240
 241                 logging_init("udevd-event");
 242                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 243
 244                 retval = udev_event_process(msg);
 245                 info("seq %llu finished with %i", msg->seqnum, retval);
 246
 247                 logging_close();
 248                 if (retval)
 249                         exit(1);
 250                 exit(0);
 251         case -1:
 252                 err("fork of child failed: %s", strerror(errno));
 253                 msg_queue_delete(msg);
 254                 break;
 255         default:
 256                 /* get SIGCHLD in main loop */
 257                 info("seq %llu forked, pid [%d], '%s' '%s', %ld seconds old",
 258                      msg->seqnum, pid,  msg->action, msg->subsystem, time(NULL) - msg->queue_time);
 259                 msg->pid = pid;
 260         }
 261 }
 262
 263 static void msg_queue_insert(struct udevd_uevent_msg *msg)
 264 {
 265         char filename[PATH_SIZE];
 266         int fd;
 267
 268         msg->queue_time = time(NULL);
 269
 270         strlcpy(filename, udev_root, sizeof(filename));
 271         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 272         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 273         if (fd >= 0) {
 274                 char str[32];
 275                 int len;
 276
 277                 len = sprintf(str, "%llu\n", msg->seqnum);
 278                 write(fd, str, len);
 279                 close(fd);
 280         }
 281
 282         export_event_state(msg, EVENT_QUEUED);
 283         info("seq %llu queued, '%s' '%s'", msg->seqnum, msg->action, msg->subsystem);
 284
 285         /* run one event after the other in debug mode */
 286         if (debug_trace) {
 287                 list_add_tail(&msg->node, &running_list);
 288                 udev_event_run(msg);
 289                 waitpid(msg->pid, NULL, 0);
 290                 msg_queue_delete(msg);
 291                 return;
 292         }
 293
 294         /* run all events with a timeout set immediately */
 295         if (msg->timeout != 0) {
 296                 list_add_tail(&msg->node, &running_list);
 297                 udev_event_run(msg);
 298                 return;
 299         }
 300
 301         list_add_tail(&msg->node, &exec_list);
 302         run_exec_q = 1;
 303 }
 304
 305 static int mem_size_mb(void)
 306 {
 307         FILE* f;
 308         char buf[4096];
 309         long int memsize = -1;
 310
 311         f = fopen("/proc/meminfo", "r");
 312         if (f == NULL)
 313                 return -1;
 314
 315         while (fgets(buf, sizeof(buf), f) != NULL) {
 316                 long int value;
 317
 318                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 319                         memsize = value / 1024;
 320                         break;
 321                 }
 322         }
 323
 324         fclose(f);
 325         return memsize;
 326 }
 327
 328 static int cpu_count(void)
 329 {
 330         FILE* f;
 331         char buf[4096];
 332         int count = 0;
 333
 334         f = fopen("/proc/stat", "r");
 335         if (f == NULL)
 336                 return -1;
 337
 338         while (fgets(buf, sizeof(buf), f) != NULL) {
 339                 if (strncmp(buf, "cpu", 3) == 0 && isdigit(buf[3]))
 340                         count++;
 341         }
 342
 343         fclose(f);
 344         if (count == 0)
 345                 return -1;
 346         return count;
 347 }
 348
 349 static int running_processes(void)
 350 {
 351         FILE* f;
 352         char buf[4096];
 353         int running = -1;
 354
 355         f = fopen("/proc/stat", "r");
 356         if (f == NULL)
 357                 return -1;
 358
 359         while (fgets(buf, sizeof(buf), f) != NULL) {
 360                 int value;
 361
 362                 if (sscanf(buf, "procs_running %u", &value) == 1) {
 363                         running = value;
 364                         break;
 365                 }
 366         }
 367
 368         fclose(f);
 369         return running;
 370 }
 371
 372 /* return the number of process es in our session, count only until limit */
 373 static int running_processes_in_session(pid_t session, int limit)
 374 {
 375         DIR *dir;
 376         struct dirent *dent;
 377         int running = 0;
 378
 379         dir = opendir("/proc");
 380         if (!dir)
 381                 return -1;
 382
 383         /* read process info from /proc */
 384         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 385                 int f;
 386                 char procdir[64];
 387                 char line[256];
 388                 const char *pos;
 389                 char state;
 390                 pid_t ppid, pgrp, sess;
 391                 int len;
 392
 393                 if (!isdigit(dent->d_name[0]))
 394                         continue;
 395
 396                 snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
 397                 procdir[sizeof(procdir)-1] = '\0';
 398
 399                 f = open(procdir, O_RDONLY);
 400                 if (f == -1)
 401                         continue;
 402
 403                 len = read(f, line, sizeof(line)-1);
 404                 close(f);
 405
 406                 if (len <= 0)
 407                         continue;
 408                 else
 409                         line[len] = '\0';
 410
 411                 /* skip ugly program name */
 412                 pos = strrchr(line, ')') + 2;
 413                 if (pos == NULL)
 414                         continue;
 415
 416                 if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
 417                         continue;
 418
 419                 /* count only processes in our session */
 420                 if (sess != session)
 421                         continue;
 422
 423                 /* count only running, no sleeping processes */
 424                 if (state != 'R')
 425                         continue;
 426
 427                 running++;
 428                 if (limit > 0 && running >= limit)
 429                         break;
 430         }
 431         closedir(dir);
 432
 433         return running;
 434 }
 435
 436 static int compare_devpath(const char *running, const char *waiting)
 437 {
 438         int i;
 439
 440         for (i = 0; i < PATH_SIZE; i++) {
 441                 /* identical device event found */
 442                 if (running[i] == '\0' && waiting[i] == '\0')
 443                         return 1;
 444
 445                 /* parent device event found */
 446                 if (running[i] == '\0' && waiting[i] == '/')
 447                         return 2;
 448
 449                 /* child device event found */
 450                 if (running[i] == '/' && waiting[i] == '\0')
 451                         return 3;
 452
 453                 /* no matching event */
 454                 if (running[i] != waiting[i])
 455                         break;
 456         }
 457
 458         return 0;
 459 }
 460
 461 /* lookup event for identical, parent, child, or physical device */
 462 static int devpath_busy(struct udevd_uevent_msg *msg, int limit)
 463 {
 464         struct udevd_uevent_msg *loop_msg;
 465         int childs_count = 0;
 466
 467         /* check exec-queue which may still contain delayed events we depend on */
 468         list_for_each_entry(loop_msg, &exec_list, node) {
 469                 /* skip ourself and all later events */
 470                 if (loop_msg->seqnum >= msg->seqnum)
 471                         break;
 472
 473                 /* check our old name */
 474                 if (msg->devpath_old != NULL)
 475                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 476                                 return 2;
 477
 478                 /* check identical, parent, or child device event */
 479                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 480                         dbg("%llu, device event still pending %llu (%s)",
 481                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 482                         return 3;
 483                 }
 484
 485                 /* check physical device event (special case of parent) */
 486                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 487                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 488                                 dbg("%llu, physical device event still pending %llu (%s)",
 489                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 490                                 return 4;
 491                         }
 492         }
 493
 494         /* check run queue for still running events */
 495         list_for_each_entry(loop_msg, &running_list, node) {
 496                 if (limit && childs_count++ > limit) {
 497                         dbg("%llu, maximum number (%i) of childs reached", msg->seqnum, childs_count);
 498                         return 1;
 499                 }
 500
 501                 /* check our old name */
 502                 if (msg->devpath_old != NULL)
 503                         if (strcmp(loop_msg->devpath , msg->devpath_old) == 0)
 504                                 return 2;
 505
 506                 /* check identical, parent, or child device event */
 507                 if (compare_devpath(loop_msg->devpath, msg->devpath) != 0) {
 508                         dbg("%llu, device event still running %llu (%s)",
 509                             msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 510                         return 3;
 511                 }
 512
 513                 /* check physical device event (special case of parent) */
 514                 if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
 515                         if (compare_devpath(loop_msg->devpath, msg->physdevpath) != 0) {
 516                                 dbg("%llu, physical device event still running %llu (%s)",
 517                                     msg->seqnum, loop_msg->seqnum, loop_msg->devpath);
 518                                 return 4;
 519                         }
 520         }
 521         return 0;
 522 }
 523
 524 /* serializes events for the identical and parent and child devices */
 525 static void msg_queue_manager(void)
 526 {
 527         struct udevd_uevent_msg *loop_msg;
 528         struct udevd_uevent_msg *tmp_msg;
 529         int running;
 530
 531         if (list_empty(&exec_list))
 532                 return;
 533
 534         running = running_processes();
 535         dbg("%d processes runnning on system", running);
 536         if (running < 0)
 537                 running = max_childs_running;
 538
 539         list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
 540                 /* check running processes in our session and possibly throttle */
 541                 if (running >= max_childs_running) {
 542                         running = running_processes_in_session(sid, max_childs_running+10);
 543                         dbg("at least %d processes running in session", running);
 544                         if (running >= max_childs_running) {
 545                                 dbg("delay seq %llu, too many processes already running", loop_msg->seqnum);
 546                                 return;
 547                         }
 548                 }
 549
 550                 /* serialize and wait for parent or child events */
 551                 if (devpath_busy(loop_msg, max_childs) != 0) {
 552                         dbg("delay seq %llu (%s)", loop_msg->seqnum, loop_msg->devpath);
 553                         continue;
 554                 }
 555
 556                 /* move event to run list */
 557                 list_move_tail(&loop_msg->node, &running_list);
 558                 udev_event_run(loop_msg);
 559                 running++;
 560                 dbg("moved seq %llu to running list", loop_msg->seqnum);
 561         }
 562 }
 563
 564 static struct udevd_uevent_msg *get_msg_from_envbuf(const char *buf, int buf_size)
 565 {
 566         int bufpos;
 567         int i;
 568         struct udevd_uevent_msg *msg;
 569         char *physdevdriver_key = NULL;
 570         int maj = 0;
 571         int min = 0;
 572
 573         msg = malloc(sizeof(struct udevd_uevent_msg) + buf_size);
 574         if (msg == NULL)
 575                 return NULL;
 576         memset(msg, 0x00, sizeof(struct udevd_uevent_msg) + buf_size);
 577
 578         /* copy environment buffer and reconstruct envp */
 579         memcpy(msg->envbuf, buf, buf_size);
 580         bufpos = 0;
 581         for (i = 0; (bufpos < buf_size) && (i < UEVENT_NUM_ENVP-2); i++) {
 582                 int keylen;
 583                 char *key;
 584
 585                 key = &msg->envbuf[bufpos];
 586                 keylen = strlen(key);
 587                 msg->envp[i] = key;
 588                 bufpos += keylen + 1;
 589                 dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
 590
 591                 /* remember some keys for further processing */
 592                 if (strncmp(key, "ACTION=", 7) == 0)
 593                         msg->action = &key[7];
 594                 else if (strncmp(key, "DEVPATH=", 8) == 0)
 595                         msg->devpath = &key[8];
 596                 else if (strncmp(key, "SUBSYSTEM=", 10) == 0)
 597                         msg->subsystem = &key[10];
 598                 else if (strncmp(key, "DRIVER=", 7) == 0)
 599                         msg->driver = &key[7];
 600                 else if (strncmp(key, "SEQNUM=", 7) == 0)
 601                         msg->seqnum = strtoull(&key[7], NULL, 10);
 602                 else if (strncmp(key, "DEVPATH_OLD=", 12) == 0)
 603                         msg->devpath_old = &key[12];
 604                 else if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
 605                         msg->physdevpath = &key[12];
 606                 else if (strncmp(key, "PHYSDEVDRIVER=", 14) == 0)
 607                         physdevdriver_key = key;
 608                 else if (strncmp(key, "MAJOR=", 6) == 0)
 609                         maj = strtoull(&key[6], NULL, 10);
 610                 else if (strncmp(key, "MINOR=", 6) == 0)
 611                         min = strtoull(&key[6], NULL, 10);
 612                 else if (strncmp(key, "TIMEOUT=", 8) == 0)
 613                         msg->timeout = strtoull(&key[8], NULL, 10);
 614         }
 615         msg->devt = makedev(maj, min);
 616         msg->envp[i++] = "UDEVD_EVENT=1";
 617
 618         if (msg->driver == NULL && msg->physdevpath == NULL && physdevdriver_key != NULL) {
 619                 /* for older kernels DRIVER is empty for a bus device, export PHYSDEVDRIVER as DRIVER */
 620                 msg->envp[i++] = &physdevdriver_key[7];
 621                 msg->driver = &physdevdriver_key[14];
 622         }
 623
 624         msg->envp[i] = NULL;
 625
 626         if (msg->devpath == NULL || msg->action == NULL) {
 627                 info("DEVPATH or ACTION missing, ignore message");
 628                 free(msg);
 629                 return NULL;
 630         }
 631         return msg;
 632 }
 633
 634 /* receive the udevd message from userspace */
 635 static void get_ctrl_msg(void)
 636 {
 637         struct udevd_ctrl_msg ctrl_msg;
 638         ssize_t size;
 639         struct msghdr smsg;
 640         struct cmsghdr *cmsg;
 641         struct iovec iov;
 642         struct ucred *cred;
 643         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 644         int *intval;
 645         char *pos;
 646
 647         memset(&ctrl_msg, 0x00, sizeof(struct udevd_ctrl_msg));
 648         iov.iov_base = &ctrl_msg;
 649         iov.iov_len = sizeof(struct udevd_ctrl_msg);
 650
 651         memset(&smsg, 0x00, sizeof(struct msghdr));
 652         smsg.msg_iov = &iov;
 653         smsg.msg_iovlen = 1;
 654         smsg.msg_control = cred_msg;
 655         smsg.msg_controllen = sizeof(cred_msg);
 656
 657         size = recvmsg(udevd_sock, &smsg, 0);
 658         if (size <  0) {
 659                 if (errno != EINTR)
 660                         err("unable to receive user udevd message: %s", strerror(errno));
 661                 return;
 662         }
 663         cmsg = CMSG_FIRSTHDR(&smsg);
 664         cred = (struct ucred *) CMSG_DATA(cmsg);
 665
 666         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 667                 err("no sender credentials received, message ignored");
 668                 return;
 669         }
 670
 671         if (cred->uid != 0) {
 672                 err("sender uid=%i, message ignored", cred->uid);
 673                 return;
 674         }
 675
 676         if (strncmp(ctrl_msg.magic, UDEVD_CTRL_MAGIC, sizeof(UDEVD_CTRL_MAGIC)) != 0 ) {
 677                 err("message magic '%s' doesn't match, ignore it", ctrl_msg.magic);
 678                 return;
 679         }
 680
 681         switch (ctrl_msg.type) {
 682         case UDEVD_CTRL_ENV:
 683                 pos = strchr(ctrl_msg.buf, '=');
 684                 if (pos == NULL) {
 685                         err("wrong key format '%s'", ctrl_msg.buf);
 686                         break;
 687                 }
 688                 pos[0] = '\0';
 689                 if (pos[1] == '\0') {
 690                         info("udevd message (ENV) received, unset '%s'", ctrl_msg.buf);
 691                         unsetenv(ctrl_msg.buf);
 692                 } else {
 693                         info("udevd message (ENV) received, set '%s=%s'", ctrl_msg.buf, &pos[1]);
 694                         setenv(ctrl_msg.buf, &pos[1], 1);
 695                 }
 696                 break;
 697         case UDEVD_CTRL_STOP_EXEC_QUEUE:
 698                 info("udevd message (STOP_EXEC_QUEUE) received");
 699                 stop_exec_q = 1;
 700                 break;
 701         case UDEVD_CTRL_START_EXEC_QUEUE:
 702                 info("udevd message (START_EXEC_QUEUE) received");
 703                 stop_exec_q = 0;
 704                 msg_queue_manager();
 705                 break;
 706         case UDEVD_CTRL_SET_LOG_LEVEL:
 707                 intval = (int *) ctrl_msg.buf;
 708                 info("udevd message (SET_LOG_PRIORITY) received, udev_log_priority=%i", *intval);
 709                 udev_log_priority = *intval;
 710                 sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
 711                 putenv(udev_log);
 712                 break;
 713         case UDEVD_CTRL_SET_MAX_CHILDS:
 714                 intval = (int *) ctrl_msg.buf;
 715                 info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 716                 max_childs = *intval;
 717                 break;
 718         case UDEVD_CTRL_SET_MAX_CHILDS_RUNNING:
 719                 intval = (int *) ctrl_msg.buf;
 720                 info("udevd message (UDEVD_SET_MAX_CHILDS_RUNNING) received, max_childs=%i", *intval);
 721                 max_childs_running = *intval;
 722                 break;
 723         case UDEVD_CTRL_RELOAD_RULES:
 724                 info("udevd message (RELOAD_RULES) received");
 725                 reload_config = 1;
 726                 break;
 727         default:
 728                 err("unknown control message type");
 729         }
 730 }
 731
 732 /* receive the kernel user event message and do some sanity checks */
 733 static struct udevd_uevent_msg *get_netlink_msg(void)
 734 {
 735         struct udevd_uevent_msg *msg;
 736         int bufpos;
 737         ssize_t size;
 738         static char buffer[UEVENT_BUFFER_SIZE+512];
 739         char *pos;
 740
 741         size = recv(uevent_netlink_sock, &buffer, sizeof(buffer), 0);
 742         if (size <  0) {
 743                 if (errno != EINTR)
 744                         err("unable to receive kernel netlink message: %s", strerror(errno));
 745                 return NULL;
 746         }
 747
 748         if ((size_t)size > sizeof(buffer)-1)
 749                 size = sizeof(buffer)-1;
 750         buffer[size] = '\0';
 751         dbg("uevent_size=%zi", size);
 752
 753         /* start of event payload */
 754         bufpos = strlen(buffer)+1;
 755         msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos);
 756         if (msg == NULL)
 757                 return NULL;
 758
 759         /* validate message */
 760         pos = strchr(buffer, '@');
 761         if (pos == NULL) {
 762                 err("invalid uevent '%s'", buffer);
 763                 free(msg);
 764                 return NULL;
 765         }
 766         pos[0] = '\0';
 767
 768         if (msg->action == NULL) {
 769                 info("no ACTION in payload found, skip event '%s'", buffer);
 770                 free(msg);
 771                 return NULL;
 772         }
 773
 774         if (strcmp(msg->action, buffer) != 0) {
 775                 err("ACTION in payload does not match uevent, skip event '%s'", buffer);
 776                 free(msg);
 777                 return NULL;
 778         }
 779
 780         return msg;
 781 }
 782
 783 static void asmlinkage sig_handler(int signum)
 784 {
 785         switch (signum) {
 786                 case SIGINT:
 787                 case SIGTERM:
 788                         udev_exit = 1;
 789                         break;
 790                 case SIGCHLD:
 791                         /* set flag, then write to pipe if needed */
 792                         sigchilds_waiting = 1;
 793                         break;
 794                 case SIGHUP:
 795                         reload_config = 1;
 796                         break;
 797         }
 798
 799         /* write to pipe, which will wakeup select() in our mainloop */
 800         write(signal_pipe[WRITE_END], "", 1);
 801 }
 802
 803 static void udev_done(int pid, int exitstatus)
 804 {
 805         /* find msg associated with pid and delete it */
 806         struct udevd_uevent_msg *msg;
 807
 808         list_for_each_entry(msg, &running_list, node) {
 809                 if (msg->pid == pid) {
 810                         info("seq %llu, pid [%d] exit with %i, %ld seconds old", msg->seqnum, msg->pid,
 811                              exitstatus, time(NULL) - msg->queue_time);
 812                         msg->exitstatus = exitstatus;
 813                         msg_queue_delete(msg);
 814
 815                         /* there may be events waiting with the same devpath */
 816                         run_exec_q = 1;
 817                         return;
 818                 }
 819         }
 820 }
 821
 822 static void reap_sigchilds(void)
 823 {
 824         pid_t pid;
 825         int status;
 826
 827         while (1) {
 828                 pid = waitpid(-1, &status, WNOHANG);
 829                 if (pid <= 0)
 830                         break;
 831                 if (WIFEXITED(status))
 832                         status = WEXITSTATUS(status);
 833                 else if (WIFSIGNALED(status))
 834                         status = WTERMSIG(status) + 128;
 835                 else
 836                         status = 0;
 837                 udev_done(pid, status);
 838         }
 839 }
 840
 841 static int init_udevd_socket(void)
 842 {
 843         struct sockaddr_un saddr;
 844         socklen_t addrlen;
 845         const int feature_on = 1;
 846         int retval;
 847
 848         memset(&saddr, 0x00, sizeof(saddr));
 849         saddr.sun_family = AF_LOCAL;
 850         /* use abstract namespace for socket path */
 851         strcpy(&saddr.sun_path[1], UDEVD_CTRL_SOCK_PATH);
 852         addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 853
 854         udevd_sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 855         if (udevd_sock == -1) {
 856                 err("error getting socket: %s", strerror(errno));
 857                 return -1;
 858         }
 859
 860         /* the bind takes care of ensuring only one copy running */
 861         retval = bind(udevd_sock, (struct sockaddr *) &saddr, addrlen);
 862         if (retval < 0) {
 863                 err("bind failed: %s", strerror(errno));
 864                 close(udevd_sock);
 865                 udevd_sock = -1;
 866                 return -1;
 867         }
 868
 869         /* enable receiving of the sender credentials */
 870         setsockopt(udevd_sock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_on));
 871
 872         return 0;
 873 }
 874
 875 static int init_uevent_netlink_sock(void)
 876 {
 877         struct sockaddr_nl snl;
 878         const int buffersize = 16 * 1024 * 1024;
 879         int retval;
 880
 881         memset(&snl, 0x00, sizeof(struct sockaddr_nl));
 882         snl.nl_family = AF_NETLINK;
 883         snl.nl_pid = getpid();
 884         snl.nl_groups = 1;
 885
 886         uevent_netlink_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
 887         if (uevent_netlink_sock == -1) {
 888                 err("error getting socket: %s", strerror(errno));
 889                 return -1;
 890         }
 891
 892         /* set receive buffersize */
 893         setsockopt(uevent_netlink_sock, SOL_SOCKET, SO_RCVBUFFORCE, &buffersize, sizeof(buffersize));
 894
 895         retval = bind(uevent_netlink_sock, (struct sockaddr *) &snl, sizeof(struct sockaddr_nl));
 896         if (retval < 0) {
 897                 err("bind failed: %s", strerror(errno));
 898                 close(uevent_netlink_sock);
 899                 uevent_netlink_sock = -1;
 900                 return -1;
 901         }
 902         return 0;
 903 }
 904
 905 static void export_initial_seqnum(void)
 906 {
 907         char filename[PATH_SIZE];
 908         int fd;
 909         char seqnum[32];
 910         ssize_t len = 0;
 911
 912         strlcpy(filename, sysfs_path, sizeof(filename));
 913         strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 914         fd = open(filename, O_RDONLY);
 915         if (fd >= 0) {
 916                 len = read(fd, seqnum, sizeof(seqnum)-1);
 917                 close(fd);
 918         }
 919         if (len <= 0) {
 920                 strcpy(seqnum, "0\n");
 921                 len = 3;
 922         }
 923         strlcpy(filename, udev_root, sizeof(filename));
 924         strlcat(filename, "/" EVENT_SEQNUM, sizeof(filename));
 925         create_path(filename);
 926         fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
 927         if (fd >= 0) {
 928                 write(fd, seqnum, len);
 929                 close(fd);
 930         }
 931 }
 932
 933 int main(int argc, char *argv[], char *envp[])
 934 {
 935         int retval;
 936         int fd;
 937         struct sigaction act;
 938         fd_set readfds;
 939         const char *value;
 940         int daemonize = 0;
 941         int option;
 942         static const struct option options[] = {
 943                 { "daemon", 0, NULL, 'd' },
 944                 { "debug-trace", 0, NULL, 't' },
 945                 { "verbose", 0, NULL, 'v' },
 946                 { "help", 0, NULL, 'h' },
 947                 { "version", 0, NULL, 'V' },
 948                 {}
 949         };
 950         int rc = 1;
 951         int maxfd;
 952
 953         logging_init("udevd");
 954         udev_config_init();
 955         selinux_init();
 956         dbg("version %s", UDEV_VERSION);
 957
 958         while (1) {
 959                 option = getopt_long(argc, argv, "dtvhV", options, NULL);
 960                 if (option == -1)
 961                         break;
 962
 963                 switch (option) {
 964                 case 'd':
 965                         daemonize = 1;
 966                         break;
 967                 case 't':
 968                         debug_trace = 1;
 969                         break;
 970                 case 'v':
 971                         verbose = 1;
 972                         if (udev_log_priority < LOG_INFO)
 973                                 udev_log_priority = LOG_INFO;
 974                         break;
 975                 case 'h':
 976                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--verbose] [--version]\n");
 977                         goto exit;
 978                 case 'V':
 979                         printf("%s\n", UDEV_VERSION);
 980                         goto exit;
 981                 default:
 982                         goto exit;
 983                 }
 984         }
 985
 986         if (getuid() != 0) {
 987                 fprintf(stderr, "root privileges required\n");
 988                 err("root privileges required");
 989                 goto exit;
 990         }
 991
 992         /* make sure std{in,out,err} fd's are in a sane state */
 993         fd = open("/dev/null", O_RDWR);
 994         if (fd < 0) {
 995                 fprintf(stderr, "cannot open /dev/null\n");
 996                 err("cannot open /dev/null");
 997         }
 998         if (fd > STDIN_FILENO)
 999                 dup2(fd, STDIN_FILENO);
1000         if (write(STDOUT_FILENO, 0, 0) < 0)
1001                 dup2(fd, STDOUT_FILENO);
1002         if (write(STDERR_FILENO, 0, 0) < 0)
1003                 dup2(fd, STDERR_FILENO);
1004
1005         /* init sockets to receive events */
1006         if (init_udevd_socket() < 0) {
1007                 if (errno == EADDRINUSE) {
1008                         fprintf(stderr, "another udev daemon already running\n");
1009                         err("another udev daemon already running");
1010                         rc = 1;
1011                 } else {
1012                         fprintf(stderr, "error initializing udevd socket\n");
1013                         err("error initializing udevd socket");
1014                         rc = 2;
1015                 }
1016                 goto exit;
1017         }
1018
1019         if (init_uevent_netlink_sock() < 0) {
1020                 fprintf(stderr, "error initializing netlink socket\n");
1021                 err("error initializing netlink socket");
1022                 rc = 3;
1023                 goto exit;
1024         }
1025
1026         /* setup signal handler pipe */
1027         retval = pipe(signal_pipe);
1028         if (retval < 0) {
1029                 err("error getting pipes: %s", strerror(errno));
1030                 goto exit;
1031         }
1032
1033         retval = fcntl(signal_pipe[READ_END], F_GETFL, 0);
1034         if (retval < 0) {
1035                 err("error fcntl on read pipe: %s", strerror(errno));
1036                 goto exit;
1037         }
1038         retval = fcntl(signal_pipe[READ_END], F_SETFL, retval | O_NONBLOCK);
1039         if (retval < 0) {
1040                 err("error fcntl on read pipe: %s", strerror(errno));
1041                 goto exit;
1042         }
1043
1044         retval = fcntl(signal_pipe[WRITE_END], F_GETFL, 0);
1045         if (retval < 0) {
1046                 err("error fcntl on write pipe: %s", strerror(errno));
1047                 goto exit;
1048         }
1049         retval = fcntl(signal_pipe[WRITE_END], F_SETFL, retval | O_NONBLOCK);
1050         if (retval < 0) {
1051                 err("error fcntl on write pipe: %s", strerror(errno));
1052                 goto exit;
1053         }
1054
1055         /* parse the rules and keep them in memory */
1056         sysfs_init();
1057         udev_rules_init(&rules, 1);
1058
1059         export_initial_seqnum();
1060
1061         if (daemonize) {
1062                 pid_t pid;
1063
1064                 pid = fork();
1065                 switch (pid) {
1066                 case 0:
1067                         dbg("daemonized fork running");
1068                         break;
1069                 case -1:
1070                         err("fork of daemon failed: %s", strerror(errno));
1071                         rc = 4;
1072                         goto exit;
1073                 default:
1074                         dbg("child [%u] running, parent exits", pid);
1075                         rc = 0;
1076                         goto exit;
1077                 }
1078         }
1079
1080         /* redirect std{out,err} fd's */
1081         if (!verbose)
1082                 dup2(fd, STDOUT_FILENO);
1083         dup2(fd, STDERR_FILENO);
1084         if (fd > STDERR_FILENO)
1085                 close(fd);
1086
1087         /* set scheduling priority for the daemon */
1088         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
1089
1090         chdir("/");
1091         umask(022);
1092
1093         /* become session leader */
1094         sid = setsid();
1095         dbg("our session is %d", sid);
1096
1097         /* OOM_DISABLE == -17 */
1098         fd = open("/proc/self/oom_adj", O_RDWR);
1099         if (fd < 0)
1100                 err("error disabling OOM: %s", strerror(errno));
1101         else {
1102                 write(fd, "-17", 3);
1103                 close(fd);
1104         }
1105
1106         /* set signal handlers */
1107         memset(&act, 0x00, sizeof(struct sigaction));
1108         act.sa_handler = (void (*)(int)) sig_handler;
1109         sigemptyset(&act.sa_mask);
1110         act.sa_flags = SA_RESTART;
1111         sigaction(SIGINT, &act, NULL);
1112         sigaction(SIGTERM, &act, NULL);
1113         sigaction(SIGCHLD, &act, NULL);
1114         sigaction(SIGHUP, &act, NULL);
1115
1116         /* watch rules directory */
1117         inotify_fd = inotify_init();
1118         if (inotify_fd >= 0) {
1119                 char filename[PATH_MAX];
1120
1121                 inotify_add_watch(inotify_fd, udev_rules_dir, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1122
1123                 /* watch dynamic rules directory */
1124                 strlcpy(filename, udev_root, sizeof(filename));
1125                 strlcat(filename, "/"RULES_DYN_DIR, sizeof(filename));
1126                 inotify_add_watch(inotify_fd, filename, IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
1127         } else if (errno == ENOSYS)
1128                 err("the kernel does not support inotify, udevd can't monitor rules file changes");
1129         else
1130                 err("inotify_init failed: %s", strerror(errno));
1131
1132         /* maximum limit of forked childs */
1133         value = getenv("UDEVD_MAX_CHILDS");
1134         if (value)
1135                 max_childs = strtoul(value, NULL, 10);
1136         else {
1137                 int memsize = mem_size_mb();
1138                 if (memsize > 0)
1139                         max_childs = 128 + (memsize / 4);
1140                 else
1141                         max_childs = UDEVD_MAX_CHILDS;
1142         }
1143         info("initialize max_childs to %u", max_childs);
1144
1145         /* start to throttle forking if maximum number of _running_ childs is reached */
1146         value = getenv("UDEVD_MAX_CHILDS_RUNNING");
1147         if (value)
1148                 max_childs_running = strtoull(value, NULL, 10);
1149         else {
1150                 int cpus = cpu_count();
1151                 if (cpus > 0)
1152                         max_childs_running = 8 + (8 * cpus);
1153                 else
1154                         max_childs_running = UDEVD_MAX_CHILDS_RUNNING;
1155         }
1156         info("initialize max_childs_running to %u", max_childs_running);
1157
1158         /* clear environment for forked event processes */
1159         clearenv();
1160
1161         /* export log_priority , as called programs may want to follow that setting */
1162         sprintf(udev_log, "UDEV_LOG=%i", udev_log_priority);
1163         putenv(udev_log);
1164         if (debug_trace)
1165                 putenv("DEBUG=1");
1166
1167         maxfd = udevd_sock;
1168         maxfd = UDEV_MAX(maxfd, uevent_netlink_sock);
1169         maxfd = UDEV_MAX(maxfd, signal_pipe[READ_END]);
1170         maxfd = UDEV_MAX(maxfd, inotify_fd);
1171
1172         while (!udev_exit) {
1173                 struct udevd_uevent_msg *msg;
1174                 int fdcount;
1175
1176                 FD_ZERO(&readfds);
1177                 FD_SET(signal_pipe[READ_END], &readfds);
1178                 FD_SET(udevd_sock, &readfds);
1179                 FD_SET(uevent_netlink_sock, &readfds);
1180                 if (inotify_fd >= 0)
1181                         FD_SET(inotify_fd, &readfds);
1182
1183                 fdcount = select(maxfd+1, &readfds, NULL, NULL, NULL);
1184                 if (fdcount < 0) {
1185                         if (errno != EINTR)
1186                                 err("error in select: %s", strerror(errno));
1187                         continue;
1188                 }
1189
1190                 /* get control message */
1191                 if (FD_ISSET(udevd_sock, &readfds))
1192                         get_ctrl_msg();
1193
1194                 /* get netlink message */
1195                 if (FD_ISSET(uevent_netlink_sock, &readfds)) {
1196                         msg = get_netlink_msg();
1197                         if (msg)
1198                                 msg_queue_insert(msg);
1199                 }
1200
1201                 /* received a signal, clear our notification pipe */
1202                 if (FD_ISSET(signal_pipe[READ_END], &readfds)) {
1203                         char buf[256];
1204
1205                         read(signal_pipe[READ_END], &buf, sizeof(buf));
1206                 }
1207
1208                 /* rules directory inotify watch */
1209                 if ((inotify_fd >= 0) && FD_ISSET(inotify_fd, &readfds)) {
1210                         int nbytes;
1211
1212                         /* discard all possible events, we can just reload the config */
1213                         if ((ioctl(inotify_fd, FIONREAD, &nbytes) == 0) && nbytes > 0) {
1214                                 char *buf;
1215
1216                                 reload_config = 1;
1217                                 buf = malloc(nbytes);
1218                                 if (buf == NULL) {
1219                                         err("error getting buffer for inotify, disable watching");
1220                                         close(inotify_fd);
1221                                         inotify_fd = -1;
1222                                 }
1223                                 read(inotify_fd, buf, nbytes);
1224                                 free(buf);
1225                         }
1226                 }
1227
1228                 /* rules changed, set by inotify or a HUP signal */
1229                 if (reload_config) {
1230                         reload_config = 0;
1231                         udev_rules_cleanup(&rules);
1232                         udev_rules_init(&rules, 1);
1233                 }
1234
1235                 /* forked child has returned */
1236                 if (sigchilds_waiting) {
1237                         sigchilds_waiting = 0;
1238                         reap_sigchilds();
1239                 }
1240
1241                 if (run_exec_q) {
1242                         run_exec_q = 0;
1243                         if (!stop_exec_q)
1244                                 msg_queue_manager();
1245                 }
1246         }
1247         rc = 0;
1248
1249 exit:
1250         udev_rules_cleanup(&rules);
1251         sysfs_cleanup();
1252         selinux_exit();
1253
1254         if (signal_pipe[READ_END] >= 0)
1255                 close(signal_pipe[READ_END]);
1256         if (signal_pipe[WRITE_END] >= 0)
1257                 close(signal_pipe[WRITE_END]);
1258
1259         if (udevd_sock >= 0)
1260                 close(udevd_sock);
1261         if (inotify_fd >= 0)
1262                 close(inotify_fd);
1263         if (uevent_netlink_sock >= 0)
1264                 close(uevent_netlink_sock);
1265
1266         logging_close();
1267
1268         return rc;
1269 }